Design Guidelines for Remote Laser welded Steel Side Door Closures

17538 words (70 pages) Dissertation

13th Dec 2019 Dissertation Reference this

Tags: EngineeringMechanicsElectronics

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This project intents to study, highlight and provide a guideline for implementing Laser Welding into the design process for side doors at Jaguar Land Rover. Specifically this project focuses on highlighting the benefits of implementing this ‘new’ technology but also providing a guideline for ‘best practice’ design implementation, which will contribute to widen the current knowledge within the business.

The studies and experiments herein presented aim to characterise this technology and should provide valuable information for its implementation or improvement in the real ‘design development process within Jaguar Land Rover.

Contents

ABSTRACT……………………………………………………….

ACKNOWLEDGEMENTS……………………………………………

AUTHOR’S DECLARATION………………………………………….

LIST OF FIGURES………………………………………………….

LIST OF TABLES…………………………………………………..

ABBREVIATIONS………………………………………………….

1 INTRODUCTION……………………………………………….

1.1 Motivation:………………………………………………….

1.2 Research Objectives:……………………………………………

1.3 Thesis Outline:………………………………………………..

2 New Technology Introduction………………………………………

2.1 Introduction:…………………………………………………

2.2 Technology Creation and Development System (TCDS):…………………….

3 Side Door Design………………………………………………..

3.1 Introduction:…………………………………………………

3.2 Door design and classification of door design:……………………………

3.2.1 Types of door design:………………………………………….

3.2.1.1 TYPE A: full one piece inner/outer door:……………………………

3.2.1.2 TYPE B: Steel sash door:……………………………………..

3.2.1.3 TYPE C: Aluminium sash/A-frame door:……………………………

3.2.1.4 TYPE D: Frameless aluminium:…………………………………

3.3 Design requirements and their Measures [KPI]……………………………

3.3.1 Product Development Engineering: (Centre of Competences)………………..

3.3.2 Advanced Manufacturing Engineering:………………………………

3.3.3 Design/Styling:……………………………………………..

3.4 Door design trends:…………………………………………….

3.5 Laser Welding:……………………………………………….

3.5.1 Benchmark:………………………………………………..

3.5.2 Remote Laser Welding:………………………………………..

3.5.3 Impact on Door design:………………………………………..

4 Door Assembly Process Development…………………………………

4.1 Introduction:…………………………………………………

5 Case Study: L538/L663/L460……………………………………….

5.1 Introduction:…………………………………………………

5.2 Case Study:………………………………………………….

6 Side Door Evaluation…………………………………………….

6.1 Introduction:…………………………………………………

6.2 Simulation:

6.2.1 Simulation requirements/standards:

6.2.1.1 Door window frame lateral rigidity:……………………………….

6.2.1.2 Door belt static strength: (compressive/expansive):………………………

6.2.1.3 Door full open overload strength:…………………………………

6.2.1.4 Door torsional rigidity:………………………………………

6.2.1.5 Side door drop req.:………………………………………..

6.2.1.6 Side door sag req.:…………………………………………

6.2.2 CAE Process:……………………………………………….

6.2.2.1 CAE testing process:………………………………………..

6.2.2.1.1 Tests:……………………………………………….

6.2.2.1.1.1 Door window frame lateral rigidity:…………………………..

6.2.2.1.1.2 Door belt static strength (compressive/expansive):………………….

6.2.2.1.1.3 Door full open overload strength:…………………………….

6.2.2.1.1.4 Door torsional rigidity:………………………………….

6.2.2.1.1.5 Side door sag/Side door drop:………………………………

6.3 Physical:……………………………………………………

6.3.1 Physical requirements/standards:…………………………………..

6.3.1.1 Physical testing process:……………………………………..

6.3.1.1.1 Tests:……………………………………………….

6.3.1.1.1.1 Door window frame lateral rigidity:…………………………..

6.3.1.1.1.2 Door belt static strength:…………………………………

6.3.1.1.1.3 Door full open overload strength:…………………………….

6.3.1.1.1.4 Door torsional rigidity:………………………………….

6.3.1.1.1.5 Side door sag/Side door drop:………………………………

6.4 Results:…………………………………………………….

6.4.1 CAE Results:……………………………………………….

6.4.2 Physical Results:…………………………………………….

6.4.2.1 Door window frame lateral rigidity:……………………………….

6.4.2.2 Door belt static strength:……………………………………..

6.4.2.3 Door full open overload strength:…………………………………

6.4.2.4 Door torsional rigidity:………………………………………

6.4.2.5 Side door sag/Side door drop:…………………………………..

7 Design Guidelines……………………………………………….

7.1 Introduction:…………………………………………………

7.2 Principles underlining the design guidelines……………………………..

7.3 Suggestions and examples………………………………………..

7.4 Detailed guidelines for RLW door design………………………………

7.5 Implementation within the JLR system………………………………..

7.6 Discussion…………………………………………………..

8 Discussion/Recommendations………………………………………

8.1 Introduction:…………………………………………………

8.2 Discussion…………………………………………………..

8.3 Results:…………………………………………………….

8.4 Recommendations:……………………………………………..

8.5 Conclusion………………………………………………….

9 Bibliography……………………………………………………

LIST OF FIGURES

Figure 1: Generic components/boundary diagram of a side door………………..

Figure 2: Side door (sash) components……………………………………

Figure 3: Type ‘A’ door design…………………………………………

Figure 4: Type ‘B’ door design………………………………………….

Figure 5: Type ‘C’ door design………………………………………….

Figure 6: Type ‘D’ door design………………………………………….

Figure 7: Current door types at JLR……………………………………..

Figure 8: BMW 7 series laser welding application (6)…………………………

Figure 9: Mercedes Benz S-class laser welding application (7)…………………..

Figure 10: RSW replacing with Laser Stitch……………………………….

Figure 11: Positioning of door in simulation………………………………..

Figure 12: Door constraints……………………………………………

Figure 13: Measurement point application…………………………………

Figure 14: Load case set-up (FS-0067)……………………………………

Figure 15: Results measurement detail (FS-0067)……………………………

Figure 16: Door – Full open overload strength model (rear door)

Figure 17: Door- Torsional rigidity (FS-0090)

Figure 18: Measurement locations……………………………………….

Figure 19: Door sag/drop CAE model set up (FS – 7000)………………………

Figure 20: Measurement point application (FS – 7000)………………………..

Figure 21: Side door in testing rig……………………………………….

Figure 22: RLW latch support………………………………………….

Figure 23: Transducer bar test set-up…………………………………….

Figure 24: Front/Rear door load application……………………………….

Figure 25: RSW doors set up…………………………………………..

Figure 26: Rig attachment…………………………………………….

Figure 27: Torsional applicator (FS – 0067)………………………………..

Figure 28: Belt static test: compressive/expansive load rig……………………..

Figure 29: Door overload test rig………………………………………..

Figure 30: Door torsional rig…………………………………………..

Figure 31: Torsion Applicator………………………………………….

Figure 32: Transducer application………………………………………

Figure 33: Door sag test rig set-up……………………………………….

Figure 34: Door drop test rig set-up……………………………………..

Figure 35: CAE test case results…………………………………………

Figure 36: Door belt static strength result…………………………………

Figure 37: Door torsional rigidity test results……………………………….

LIST OF TABLES

Table 1: Jaguar Land Rover – Side Door CAE Req…………………………..

Table 2: CAE Test requirements/procedures……………………………….

Table 3: Load case application for ‘Door window frame lateral rigidity’ simulation….

Table 4: Physical test requirements/procedures……………………………..

Table 5: Door window frame lateral rigidity results………………………….

Table 6: Door sag – untrimmed – results………………………………….

Table 7: Door sag – trimmed – results…………………………………….

Table 8: Door drop – trimmed – results…………………………………..

ABBREVIATIONS

BOD Bill of Design
BOP Bill of Process
BiW Body-in-White
COG Centre of Gravity
DOF Degrees of Freedom
JLR Jaguar Land Rover
KPI Key Performance Indicators
LW Laser Welding
OEM Original Equipment Manufacturer
RSW Resistance Spot Welding
RLW Remote Laser Welding

CHAPTER 1

1         INTRODUCTION

It cannot be denied that the automotive world is at a position of change, with an ever continuous drive towards electrical and autonomous vehicles. ‘The automotive industry is in the midst of an unprecedented transformation aimed at doubling fuel economy by 2025 and reducing the weight of automobiles by up to half a ton, while maintaining or improving safety. Today’s engineering imperatives are to do more with less, accelerated time to market, minimise investments and product costs, and differentiate with improved competitive designs’. (1) With the increasing awareness of customers to environmental issues, ever repeating oil crises and government incentives, there is a bigger and bigger push for electrical vehicles. ‘In 2030, the share of electrified vehicles could range from 10 percent to 50 percent of new-vehicle sales. Adoption rates will be highest in developed dense cities with strict emission regulations and consumer incentives (tax breaks, special parking and driving privileges, discounted electricity pricing, et cetera).’ (2)  Best examples are the city of Zermatt that has banned ‘combustion engineer cars since 1961 and Germany’s latest incentive is to ban ‘combustion engines car’ right across Germany by the year 2030. The ever-increasing expectations of customers has put severe pressure on the automotive industry to meet these targets and continue to develop light-weight, cost effective, safe and fashionable cars. With companies, such as Tesla (Model X/S) raising the bar, other OEM’s such as Nissan/Renault and BMW working hard to follow by releasing lightweight cars with ever larger ‘mile’ ranges. The recent developments and product releases have put additional pressure on OEM’s such as Jaguar Land Rover to follow suit and to develop the ‘next big thing’ in this trend. This is where it becomes complicated.  Even though it can be said that the trend within the automotive industry is clearly ‘electrical’ and consequently manufacturers are trying to reduce the ‘weight’ and ‘costs’ as much as possible, but what does that actually mean to the customer (internally and externally) and how this step is actually achieved.

Producing such a product can bear many risks for the business and therefore key aspects or ‘Key Performance Indicators’ (KPI’s) need to be identified and defined to make the product a success. The aim of this thesis is to explorer and identify what KPI’s are achievable and what affect they have on all areas of the business and consequently produce guidelines for the business in order to be able to adapt quickly to cope with the pressure whilst also understanding what impact these changes have.

1.1        Motivation:

Due to the authors background this paper will be focusing on ‘Side Door Systems’ and the developments of that area and therefore other areas of the vehicle have been excluded. Due to the above stated reasons, the company Jaguar Land Rover is forced/driven to review its current ‘Bill of Design’ (BOD) and its current ‘Bill of Process’ (BOP) of side doors, with the aim to reduce overall weight and cost. During this review/deep dive it was identified by Jaguar Land Rover (JLR), that a new ‘future company strategy’ had to be developed to be able to stay competitive. The system strategy paper that has been compiled, covers the ‘Doors Body – in – White (BiW)’ as well as key systems that impact on the selection of the best door type. It was identified that although the JLR steel door BOD and BOP is competitive, improvements can be made. Additionally, although a steel side door construction is generally the lower cost option, compared to aluminium or other manufacturing methods, and the most common application, it is heavy and therefore is a clear need/requirement to increase the application of an aluminium BOD/BOP for all side doors in the Jaguar Land Rover portfolio. Unfortunately Aluminium is also more expensive than steel, especially the current door construction design used for aluminium doors in JLR. It is predicted that the application of a ‘Laser Welding Process’, whether that will be with ‘Aluminium or Steel’, could potentially deliver an optimised cost and weight solution but it is unclear whether this application delivers all the KPI’s and the brand typical design language the company aspires to. In either case, these types of processes bring different parameters with them, which need to be fully understood.

The purpose of this paper is to identify, explain and validate the implications of introducing a new process into JLR, to highlight the key system interfaces that are affected by the introduction of this new technology and whether this new process is suitable for achieving JLR KPI’s and to identify the benefits to the ‘customers’ of this new technology, by completing the following research objectives:

1.2        Research Objectives:

  1. Understanding the process of ‘new technology introduction into Jaguar Land Rover: Understanding the specific gateways and what needs to be delivered at these key gateways in order to successful implement the new technology.
  1. Validation whether new technology can deliver JLR attributes and KPI’s of the different ‘customers’.  A detail analysis of what actual KPI’s the new technology can deliver.
  1. To understand what the new technology enables for certain areas of the business to do. Once the KPI’s have been identified, it is to understand which KPI’s can actually be implemented and to which areas of the company. (Design, Engineering, Manufacturing)
  1. Gain understanding of whether the new technology introduction satisfies Side Door requirements? To gain the understanding how the RLW doors perform to the set requirements and how that compare to a convention door construction.

1.3        Thesis Outline:

This thesis will discuss the methodology of introducing a ‘new’ technology into Jaguar Land Rover, as well as exploring the advantages and the ‘Key Performance Indicators’ enablers for Remote Laser Welding.

The content and purpose of the individual chapters are presented below:

In Chapter 2 the generic process of introducing a new technology into the business will be descripted and discussed. More specifically this will be discussed in the context of Jaguar Land Rovers process, the Technology creation and development system (TCDS), and how this is implemented and its importance, specifically to the Side Door Systems.

Chapter 3 will be discussing ‘Door Design’ including: Door types/styles and the classification of door design. Also, it will be exploring the specifications of doors within Jaguar Land Rover (KPIs) (Separated into two categories: Design from a creative point of view) and design from an Engineering point of view. To sum up the general trends for door design within the automotive Industry will be discussed with examples and a comparative analysis.

Chapter 4 will be discussing the general door assembly process development within Jaguar Land Rover.

Chapter 5 will be describing and discussing the general requirements of a side door within the company and additionally will discuss the evaluation process of the side doors. E.g. testing and CAE/FEM analysis.

Chapter 6 will be discussing the case study that was conducted on the evidence discussed in the previous chapters. This was demonstrated in a conventional Evoque steel door.

Chapter 7 will be using the information obtained from the case study and the other processes to describe and discuss the ‘Principles underlining the design guidelines, more specifically a more detailed guideline for RLW laser door design and discuss the implementation within the Jaguar Land Rover process.

Chapter 8 will be a discussion of the findings and making suggestions and recommendations for future development.

CHAPTER 2

2         New Technology Introduction

2.1        Introduction:

In order for a business to be competitive and/or to be the leading company in its field, it needs to continue to develop and/or introduce new technologies into their processes. This can probably be said for manufacturing more than any other industry. The introduction of new technology is a vital part for the survival of a company process as it can enable the company to compete through volume increase, cost cutting and quality output. But it can also be a complicated process. A process, if not implemented correctly can lead to the failure of the new technology, which in turn can cost the company a lot of money or worse loose the company its competitive edge and lead to the end of the company. Therefore it is vital to get the process correct and companies such as JLR, have set up a specific process of introducing new technologies into their process structure. If the technology has not been specifically designed or developed by the said company, the process needs to be tested and fine-tuned to the specific company’s needs.

The purpose of this chapter is to identify and explain the new technology development and introduction process at JLR and setting the background for this thesis research. It will try to explain the process with references to (R)LW. At JLR the new technology introduction process is called ‘Technology Creation and Development System’ (TCDS), which has its ties to the ‘Product Creation and Development System’ (PCDS).

2.2        Technology Creation and Development System (TCDS):

‘Innovations and new technologies are significant generators of revenue, especially if they can be introduced as class leading features. They are also a significant contributors to the competitiveness in feature content, vehicle performance, and environmental credentials, all which contribute to the bottom line of the business. The ability to develop innovative features and technologies on time, to the right cost, and to high quality will be a major factor in the future success of Jaguar Land Rover’. (3)

The TCDS framework is designed to help deliver this.

‘The main objective of this upfront work is to develop new technologies for implementation into vehicles from the initial concept to the point where the technology can be deployed on a vehicle at acceptable risk within the PCDS.’

These deliverables are designed to help technology project teams identify failure modes (technical, business and project), as early as possible. This document explains the execution of the deliverables in the TCDS. TCDS is design to provide the Standard Operating Procedure for development of ideas and technologies, to the point where they can be confidently applied to vehicles using the Product Creation & Delivery System, PCDS.’

In another development, GTDS is being repranded as the TCDS. One of the major implications of this change is the addition of an extra ‘Concept Selection’ <CS> gateway.

The TCDS has its have their foundations in the GPDS framework, which has been developed and improved and has now replaced by the former.  The GPDS is a common framework that was originally developed by the Ford Automotive company to support the delivery of vehicles across all the brands within the ford portfolio. Key events and achievements in GPDS are monitored through a number of gateways from pre-programme to mass production and are laid out by describing activities through a number of work streams (e.g. Program Management, Finance, Development & Engineering, Purchasing, etc).  The whole GPDS process is supported by process sheets that describe the high level process steps and deliverables that need to achieved at each gateway for each of the workstreams.  The figure below summarises the key gateways and activities within GPDS and detailed descriptions of these can be found in [1].

GTDS (Global Technology Development System) – This process has been developed to support the development of research and advanced engineering activities from concept to implementation ready (IR).  The structure of the workstreams, gateways, format and deliverables within GTDS are different to GPDS.  The timing of the GTDS projects is based from a KO event to a proposed finish time.   The figure below summarises the key stages of the GTDS process around the systems engineering ‘V’.

The basic idea is to get the new technology implementation ready (into the process) without any failures or errors.

As the GTDS system is being replaced by the PCDS this paper will focus on the latter.

Past research involvement

Already between TS and CS of the gateways

CHAPTER 3

3         Side Door Design

3.1        Introduction:

The success of a business or the success of a product can be assessed on the basis of a number of different factors. These factors can vary depending on the type of the organisation or the type of the industry. (e.g.: automotive vs aviation and/or design lead vs engineering lead). These factors or ‘Key Performance Indicators’ (KPI) as they are also known as, can help an organisation define and measure the progress towards a specific goal. These KPI’s can be identified by an organisation as ‘must haves’ in order to be measure as successful.  This can be applied to any aspect of the business, ranging from a high level overview, measuring the overall success of the business down to the production of a specific product or a part of a product (assembly). ‘Key Performance Indicators (KPIs) are quantifiable metrics, or measurements, that relate to specific success attributes that reflect the organization’s performance. As such, the selection of the specific KPIs to be used may differ widely from one organization to another – or even between and among departments within the same organization. In order for a KPI to have maximum value, it must be clearly defined, quantifiable, and relatively easy to measure. Metrics that are vague in definition; qualitative or subjective in nature; and next to impossible to collect, interpret and analyse will not serve as a good basis for a KPI.’ (3) The products “must haves” are identified to be necessary in order for the product to be either, a success in its own right or at least be contributing to the overall success of a product. The “vehicle door system” has to fulfil certain key performance indicators to be deemed “successful” and/or contribute to the overall success of a vehicle by meeting its own KPI’s. Within JLR the ‘side door’ KPI’s affect and influence many different areas across the business and need to fulfil many aspirations.

Side Doors on a vehicle fulfil several different purposes. It can be said that side ‘doors are amongst the most important and most complex vehicle parts.’ (4)  Not only do they allow the ‘human’ engagement with the ‘vehicle’ (HMI – Human/Machine interface) appropriately and comfortably, but also plays a large part in conveying and carrying the overall design language of the specific vehicle and/or a specific brand. e.g. Land Rovers sharp A-Post corner/Jaguar’s fuselage barrel side shape). Additionally they provide key structural support to the vehicle, giving structural integrity to the body (side) frame and protecting the occupant from any side impact during a crash situation. There are many different types/styles of side doors used on vehicles today, which can range from conventional side doors (front hinged), rear-hinge side doors (suicide doors), sliding doors, butterfly winged doors, and gull-winged. This specific paper will focus more on the conventional side door as this seems to be the industry standard for vehicles with a large manufacturing volume.  Having said that, even though there are a number of different ‘style’ of doors, it seems to be that the general geometry of a side door is similar if not the same. Whether that is a front hinged, a rear hinged door or even a sliding door, it seems to be that the general components of a side door do not vary hugely from one side door to the next.

Figure 1: Generic components/boundary diagram of a side door

3.2        Door design and classification of door design:

Principally speaking the conventional side door design architecture has not changed drastically from the introduction of stamped doors in the 1930’s to the present day. Of course modifications have been made and many component improvements have been introduced, as well as new materials but its design itself has not changed. Most vehicle side doors BiW construction contain the following components: an outer panel (1), an inner panel (2), a halo/inner reinforcement (3), a waist reinforcement (4), a hinge/check-arm reinforcement (5) and a side intrusion beam (6). Some doors also include a latch reinforcement. (7)

Figure 2: Side door (sash) components

Over the years at Jaguar Land Rover a number of different styles of door designs have been developed. Each with a different fulfilment of KPI’s and implications of costs.

3.2.1        Types of door design:

3.2.1.1       TYPE A: full one piece inner/outer door:

This BiW door construction design features a full piece inner (1) and full piece outer (2) that contain a hinge reinforcement (3), waist reinforcements (4) and a side introduction beam. Due to press feasibility complications, this construction type is usually used in steel which brings with it a weight impact but is the cheapest cost option that JLR have. Having said that there are variance in this door type. The cheapest version is to have a complete door outer without any finisher application but is feasible to add them. With the application of finishers, cost and weight can increase but allows more design variation and premium look (e.g. floating roof graphic and B-Post capping’s).  Type ‘A’ doors (without finisher) can be seen on the current Defender model and the same type of door just with a finisher application can be seen on [previous] Ranger Rover Sport model.

Figure 3: Type ‘A’ door design

3.2.1.2       TYPE B: Steel sash door:

This BiW door construction design features a half seized outer panel (1), a full height inner panel (2), a halo/inner reinforcement (3), a waist reinforcement (4), a hinge/check-arm reinforcement (5), a side intrusion beam (6) and a latch reinforcement. (7)

Figure 4: Type ‘B’ door design

The steel sash door design is the most commonly used within the company as it allows a higher number of possibilities to design aspiration and delivers a premium exterior appearance, as well as delivering improved vision angles in comparison to Type ‘A’ doors. Although this is a bonus in achieving the KPI’s for Design, this has an impact on cost and weight. PD KPI’s.  Type ‘B’ doors can be seen on vehicles such as XF, Discovery Sport, [new] Discovery,  F-Pace and [new] Ranger Rover Velar.

3.2.1.3       TYPE C: Aluminium sash/A-frame door:

This BiW door construction is out of aluminium and features a half sized outer panel (1), a half sized door inner (2), a waist reinforcement (4) a full height hinge reinforcement (5), a side intrusion beam (6) and a latch reinforcement (7).  Instead of a separate ‘halo’ reinforcement like on the steel sash door construction, this design features a complete upper door frame construction made out of castings and extrusions. (3) This A-Frame construction is then attached/joined into the door inner panel. Although this specific design delivers a premium exterior appearance with the best framed vision angles and a weight reduction it is very expensive. Additionally the door frame is not made in-house and supplied to the company which means knowledge and control is given away to an outside source. Type ‘C’ doors can be seen on vehicles such as the current Range Rover and current Range Rover Sport.

Figure 5: Type ‘C’ door design

3.2.1.4       TYPE D: Frameless aluminium:

Although this specific door design is not used on a large volume of vehicles, it is worth mentioning. This BiW door construction is also out of aluminium and features a half sized outer panel (1), a half sized door inner (2), an outer waist reinforcement (3), an inner waist reinforcement (4), a hinge reinforcement (5), a side intrusion beam (6) and a latch reinforcement (7). Due to the ‘frameless’ feature this door construction delivers a premium exterior appearance with the best vision angles, as well as a good ingress measurement and good weight properties but there is a high risk in manufacturing for setting the doors/glass to achieve this premium look and the costs that are saved on the doors is pushed onto the ‘Sealing’ and ‘Regulators’ team due to increased complexity and functionality. This door design currently used on the F-Type convertible and coupe models.

Figure 6: Type ‘D’ door design

Each of these door constructions have their own advantages and disadvantages. Depending on the type of the vehicle, for which type of customer and for which kind of market segment each of these door constructions might or might not be the right choice for achieving the desired KPI’s. For example, for a vehicle that is intended as an entry vehicle for customers that might be interested in the ‘Brand’ Jaguar or Land Rover and it is intended to be a urban utility vehicle, the Type ‘A’ type doors might be the best option but for a vehicle that is intended to be more premium then the Type ‘B’ doors might be a better and more cost effective option. They might be a higher piece price and higher investment cost but it gives the company what it needs. The Type ‘C’ and Type ‘D’ doors are perfect for the upper premium vehicle as it is intended for a market, where the customer is willing to pay for the extra premium design and therefore the cost of production can be covered. This is also applicable for weight targets. For a market segment where the competitors have a low CO2 emission it is important that a specific weight target is achieved and therefore it is important every’ Kg’ can be saved where possible. Although the Type ‘C’ door is a more expensive door compared to the Type ‘B’ door due to the price difference of Steel to Aluminium but due to the weight saving that Type ‘C’ brings with it, it might be a business case and a trade off in KPI’s (weight target vs cost) worth considering.

Figure 7: Current door types at JLR

3.3        Design requirements and their Measures [KPI]

Premium vehicles such as the products made by JLR have to fulfil and meet many expectations and desires from the customers, internal and external ones. As the premium vehicle market is a highly competitive market, the smallest detail (positive or negative) can make a difference in the customers purchasing the vehicle or in the case of the internal customer, not achieving their own set KPI’s. Due to this high competitive market, automotive OEM’s (Original Equipment Manufacturers) continuously try to improve and develop their products further in order to gain an advantage over their competitors. These advantages are identified by the company as KPI’s necessary to be successful. For example, due to the high fuel prices in combination with the environmental awareness of European customers, these OEM’s continue to thrive to reduce the CO2 emission of their vehicles by reducing the overall weight of their vehicles. Additionally to making their vehicles more competitive, the OEM’s continuously are looking for possibilities to make their products more cost effective or in simplest terms cheaper to manufacture.  These advantages and further developments might at times not be achieved with the current conventional technology at hand and a new technology is needed. In order to develop a technology further and be able to integrate the technology into the Bill of Design, Bill of Process and into the manufacturing plants, a business case needs to be created to see if this technology is viable, cost effective and satisfies enough KPI’s of the business. It is important to consider that some KPI’s or the ones of certain components can and will most likely affect more than one area of the business.  The more [KPI] are satisfied or achieved by a product or a system the better. The side door system of a vehicle is a perfect example of this. The side door system on a vehicle, especially for an SUV, can be a very complex system and due to its nature, use and location on the vehicle, they affect and influence many different areas of the vehicle and the business. There are three main key areas of the business that have been identified that are all interconnected and affected by side doors and these are: Product Development Engineering (PD)/Centre of Competence (CoC), Advanced Manufacturing Engineering (AME) and Design (Styling). All three areas have their own KPI’s that need to be satisfied and that contribute to the end design of a side door system.

3.3.1        Product Development Engineering: (Centre of Competences)

For the core ‘Product Development’ (PD) Team there are certain KPI’s of crucial importance that come before any of the others and these are connected primarily with the overall performance of the side door. During the development of the side door system, key criteria’s such as ‘door frame stiffness, door drop and sag, the overall structural properties that contribute to the crash requirements and legal vision requirements need to be thought off, while designing the side doors. The consideration of these criteria’s will directly affect what design is feasible both in an engineering point of view and from a styling point of view. Whilst trying to achieving the ‘design/styling’ aspiration PD needs the KPI’s that are dictated by the capabilities of the manufacturing plant. This includes floor space within the factory, the cell structure and layout as well as the actual pressing, tooling and joining capabilities that dictate what PD can design to. (e.g.: pressing feasibility, flange length requirements for RSW)

3.3.2        Advanced Manufacturing Engineering:

Manufacturing needs to deliver and support PD in their effort to deliver design aspiration, while trying to meet their own KPI’s. Manufacturing need to meet a set volume content to a given volume with a given manufacturing method to a set quality standard. All three items are heavily affected by the actual design of the side door. With the given joining technology that is available certain standards are required in order to be able to produce the parts that are needed. That means the flange length of the components is crucial to be able to actually join them appropriately. If this was not the case, then meeting the expectations of ‘high quality’ components would not be met and the company would be losing money due to rejected parts as well as not being able to produce the number of doors for the volume that is desired or needed. Additionally the technology available to a manufacturer can be a larger driver to the Bill of Design (BOD) and the Bill of Process (BOP).

3.3.3        Design/Styling:

The ‘Design’ team of JLR needs to come up with new models and new designs that are fashionable and modern and will inspire customers to purchase the cars of the future but at the same time are limited or dictated by the capabilities of the two other areas. Design will always be pushing for new and better ways to execute their aspirations and wished and what is their interpretation of the ‘brands’ design language but in themselves are dictated and regulated by KPI’s of other areas such as ‘Marketing’ which try to convey they wishes and desirers of the market and the customers. One of the driving attributes is the ‘vision angles’ and the ‘ingress/egress’ of the vehicle that gives the customer a more open feeling within the car, which in turn drives the aspiration to reduce the overall cross section of the door frame and the flange length which both allows a better vision.

3.4        Door design trends:

Benchmarking studies of competitor vehicles being released into the market, a certain trend can be identified. Forced through legislations and the shift of customer awareness, a general motivation amongst OEM’s can be detected. It can be said that the overall aim seems to be: to reduce the weight of the side doors construction, reduce the cost of the overall product while still maintaining the overall design graphic/language without compromising the experience for the customer. Having said that, a difference can be seen between the premium vehicles and the ones located at the cheaper spectrum of the market. In the low cost vehicles it can be seen that there is a common trend for either a ‘Type A’ door construction, which can allow for a very cheap and simple door construction with just a full piece outer and inner, or at times a ‘Type B’ door construction with a slightly more expensive and complex door construction that includes door finishers. The Type ‘A’ type style door design can be upgraded with the inclusion of finishers, but this drives cost and complexity into the door systems. Depending on the volume and the business case it might make sense to change to a Type ‘B’ style door if ‘Design/styling’ so desires. If there is a desire for a more ‘graphic’ appearance for a Type ‘A’ door, a decal option could be added instead of actual finishers. The ‘decal’ are a cheaper option than actual finisher put can drive complexity into the manufacturing process for applying them on the track-side and might potentially not meet design aspiration, especially if the brand is premium. Best examples for a typical Type ‘A’ door construction is the Jeep Wrangler, with a complete door outer and complete door inner panel and no finisher applications above waist. The upscale example cost option for a Type ‘A’ door construction is the Skoda Yeti with a full door outer panel and a C-Post finisher capping. Amongst the JLR competitors, there are many examples that use a Type ‘B’ door construction and it can be assume this is due to the possibility of variety and options it allows. The OEM can offer a variety of different cost options to their customers without changing the BOP and/or the BOD which in turn allows for a high volume production without the increase of complexity to manufacturing. Additionally the door construction is more accommodating to design aspiration and allows a cost walk upwards to a more premium execution by adding more expensive finishers and more exclusive bright-work. Mini Countryman, Jeep Renegade, Skoda Octavia, Porsche Panamera, Audi Q7 and Porsche Macan, just to name a view, are perfect examples of Steel Sash door construction.

At the upper scale of premium cars, different types of door construction have begun to emerge on the market with Audi A8, BMW 7 series and the Mercedes C class going one step further by introducing Laser Welding into their door design. With the introduction of this new technology differences of the actual door design can be observed.

3.5        Laser Welding:

“Laser welding has gained considerable acceptance in the automotive industry because it provides several advantages over other joining processes e.g. Resistance Spot Welding.  Benefits include high productivity, good flexibility, and low maintenance and energy costs along with the ability to produce strong welds.” (5) Over the recent years, Remote Laser Welding (RLW) has become an emerging joining process in the automotive industry. Although other laser welding techniques are currently used, RLW provides manufacturers with remarkable advantages such as high speed, high quality and potential low(er) manufacturing costs (at a high volume), compared to other laser welding techniques. Original Equipment Manufacturers (OEM’s) such as VW, AUDI and BMW with a less volatile company history compared to Jaguar Land Rover have invested heavily in Laser Welding technology’s in the last few decades and have increasingly been using it on current or new models. RLW is a technology that can potentially provide Jaguar Land Rover with many advantages that need to be explored.

3.5.1        Benchmark:

At an automotive conference BMW presented their latest laser welding application on their BMW 7 series (Figure 8) side door. As it can be seen LW has been used as a joining methods for large portions of the side door, especially around the periphery of the upper frame of the door as well as for below waist. Additionally it is interesting to notice that this is for an aluminium door. This demonstrates that LW is a feasible option for application.

Figure 8: BMW 7 series laser welding application (6)

Mercedes-S class:

At the another conference in 2013, Mercedes presented their laser welding application on the (back then) new S-Class side doors, which has since then been implemented into the new C-Class side doors. (2015 Model). As it can be seen the Mercedes has a slightly different approach than the BMW series, with LW application only in the upper frame area above waist and using conventional joining techniques such as riveting. This is again for Aluminium Side Doors.

Figure 9: Mercedes Benz S-class laser welding application (7)

3.5.2        Remote Laser Welding:

In addition, with the application of adhesives in some areas, the primary joining technology applied within JLR for ‘steel doors systems’ is RSW. Unfortunately the parameters needed for a successful spot-welding application (e.g. component flange length of 16 mm and welt gun access) dictate a specific frame section and also limit the possibilities of developing the door design further. ‘Laser Welding with a filler wire’ or ‘Closed-coupled laser welding’ as it is sometimes called, is currently application ready only on one JLR model, the new Discovery Sport, and is only applied to the tailgate area. Although a higher complex tailgate set-up was possible due to this technology compared to what would have been possible with spot welding the laser welding is only applied for non-structural and cosmetic welts.  From the benchmarking conducted it is known that other OEM’s such as AUDI and BMW are already using close-couple laser welding not only on the models that have steel doors, but also on aluminium doors. It is also known that these companies have been continuously been testing and developing ‘Remote Laser Welding’ over the last few years and seem to be ready to implement this knowledge into new models. Although close-coupled welding allows the application of a smaller stitch weld, compared to spot welding, there is still the requirement of a filler wire and close contact to the components that are welded. Remote Laser Welding uses a laser source to apply the stitch welt but due to optical mirrors that guide the laser to the correct position the actual robot is further away from the work piece. With the only need to a clear field of vision to the work piece, the robot is able to apply a stitch weld without a direct access. This can be incorporated into the design of the door.  ‘While conventional laser welding uses a robot or a Cartesian system to manipulate the beam or work piece, remote welding uses a relatively long focusing optic (hence “remote”) and scanning mirror(s) to manoeuvre the focused beam over the work piece. But what really increases the beam on time is the significant reduction in off time. The light weight and highly dynamic scanning mirrors enable extremely fast indexing in-between welds, which simply means the laser is spending more time joining parts and much less time waiting to be in position to create the next weld. The results are higher throughput, less stations, and lower costs.’ (8)

3.5.3        Impact on Door design:

The benchmarking process demonstrates that the application of LW is feasible and applicable and can bring benefits to the door frame design that needs to be understood in more depth. It is understood that changing the joining technology of the upper frame of the side door, brings the biggest benefit to the door design, it was decided to focus the study on the same application as Mercedes did on the C-Class. As the size of a normal laser weld stitch is much smaller in width compared to a conventional spot welding foot-print a lot of space can be saved applying the welt. Depending on which type of laser welding method is applied additional benefits can be gained as the need for direct access to the work piece is no longer required e.g. RLW. Though this the redesign of the frame is a possibility to reduce weight and the section size, but it needs to be understood whether the actual method produces a strong enough welt for the upper frame. This will be explored further in the Case Study example.

CHAPTER 4

4         Door Assembly Process Development

4.1        Introduction:

Although the new technology needs to fulfil many different KPI’s and can act as an enabler to other KPI’s across the business it needs to be ensured that the new technology also enables easy assembly. In the case of side doors and JLR, the new technology needs to enable manufacturing to be able to join, assembly and construct the door in a robust fashion. The RSW process has been refined and developed into a complete robust process where every step fits and everybody knows what needs to be done. The new technology needs to achieve that and preferable unlock/unfold other KPI’s at the same time. E.g. faster track time and increased floor space.

CHAPTER 5

5         Case Study: L538/L663/L460

5.1        Introduction:

Following the benchmarking and the theoretical assumptions in regards to what was aimed to be achieved and determining out the individual requirements of the different areas of the company a case study on several different types of vehicles and doors was conducted to see if the theory and the assumptions were correct and could be achieved.

5.2        Case Study:

In order to gain a better understand of what affect, replacing the spot welds with RLW stitches, had on the overall performance on the door system and to be able to have a robust comparison a L538/Evoque door construction was used. This was done as there was enough data available that was understood and demonstrated how the door BiW door construction performed with conventional spot-welds. The upper-frame of the door was identified as the area with the highest potential of improvement and development as well as based on the Mercedes S-class (Figure 7). Through development work done by the Warwick Manufacturing Group (WMG) on the Navigator project, where the ideal RLW parameters for stitch welding were identified, it was decided to replace the RSW with a 25 mm long and 1 mm wide welt stitch.

Figure 10: RSW replacing with Laser Stitch

The lower part of the door was manufactured using the convention RSW welding technology, and then delivered to WMG who joined the upper frame with the halo using RLW.  These door where then delivered to the Halewood plant for complete assembly of the door inner to the door outer panel and then eventually coated with E-coat. Eventually the door system was then delivered to the testing department to conduct all the necessary evaluation testing.

L663:

In addition to the L538 Door there was a case study conducted for L663 to identify what benefits could be achieved with RLW. Different to the L538 study, no actually physical models were produced and no physical and CAE testing was conducted either. This case study was primarily to see, in a CAD world environment, what would be achievable. Although this case study was conducted for an Aluminium door frame and Self-Piercing Rivets (SPR’s) are used as a joining technology, similar principles could be applied to a Steel door as for a like for like using RSW.

CHAPTER 6

6         Side Door Evaluation

6.1        Introduction:

The purpose of this chapter is discuss and highlight the simulation and physical testing process conducted at JLR. A large part of the design component development process, is the simulation and testing of parts, components, and/or systems. This is done to identify whether the components meet the set requirements or in the case of not meeting them, what changes and improvements would have to be made to meet them.

The physical testing of components or systems is time consuming and costly. In order to save time and reduce costs, Computer-Aided Engineering (CAE) is applied.  Using ‘Computer Aided Engineering/Simulation’ software to create realistic models of the actual components or systems, allowing the engineers to continuously improve and further develop their components, until they meet the set requirements. Whether that be, safety standards and requirements set by an external body or standards and requirements set internally to meet quality and customer expectations. This can save time and reduces the usage of materials, machines and tools, and therefore reduces the overall costs of the components, of the process and therefore be able to make the component overall cheaper.

To be able to gain a better understanding, not only of the ‘Remote Laser Welded’ Door performance in the first instance and/or if they meet the set requirements, but also how it compares to a conventional ‘Spot Welded Door’ of the same construction, CAE simulations and physical tests were conducted. The actual door construction of the two types of doors (RSW and RLW) was exactly the same and for both tests (simulation and physical) a conventional right hand side steel door construction, same as on the Evoque vehicle (L538) was used.  The doors were then run through the testing methods normally applied at Jaguar Land Rover.

6.2        Simulation:

‘A typical CAE process comprises of pre-processing, solving, and post-processing steps. In the pre-processing phase, engineers model the geometry (or a system representation) and the physical properties of the design, as well as the environment in the form of applied loads or constraints. Next, the model is solved using an appropriate mathematical formulation of the underlying physics. . Typically the software, used for this simulation, is ‘ABAQUS v6. 13.1 Non-Linear Implicitly Analysis and Hypermesh v13.0’. In the post-processing phase, the results are presented to the engineer for review.’

For the CAE simulation and within the side door requirements testing procedures, 6 key main tests were identified and applied.

6.2.1        Simulation requirements/standards:

All JLR vehicles need to fulfil/meet a certain number of requirements that are either set internally (e.g.: quality) or are dictated from external sources (e.g.: legislations). Having said that most internal requirements are set in order to ensure that internal and external customer expectations are met. These requirements are made up of, but are not exclusive to, ‘legal’ safety requirements (NCAP etc.), environmental requirements (CO2/kg, weight etc.) and quality requirements. The standards/requirements then dictate the guidelines for testing procedures.

Using the Table 1 below as reference, the 6 key test are:

6.2.1.1       Door window frame lateral rigidity:

This test, following the procedure ‘TPJLR.01.188’ and ‘TPJLR.01.189’ for simulation and physical respectively, is to indicate whether the stiffness and the potential deflection of the upper frame of the door meets the requirements set in ‘FS-7019’. When the vehicle is traveling at a high velocity (tested to 160 mph) the forces/wind pulls the upper frame of the door outboard (Blow-out). This can lead to a gap between frame/sealing to the body-side and can lead to water inlet and noise degradation within the cabin. This specifically can become an issue on the Land Rover vehicles due to their height and the traditional/brand typical sharp A-Post corner.

6.2.1.2       Door belt static strength: (compressive/expansive):

This test, following the procedure ‘01.03-C-402’ and ‘01.03-L-438’for simulation and physical respectively, is to measure whether the overall stiffness and rigidity of the waist belt line of the door meets requirement ‘FS-0067’. This is important for the structural integrity of the overall door and helps the side crash characteristics of the door and therefore of the vehicle.

6.2.1.3       Door full open overload strength:

This test, following the procedure ‘01.03-C-404’ and ‘01.03-L-441’ for simulation and physical respectively, is to see if there is enough structural integrity within the BiW to withstand any deformation (set by the requirement ‘FS-0089’) in case the door is pushed open past its extreme opening angle. The test is used to simulate the effects when an external horizontal load acts on the door when the door is already at the full open position.

6.2.1.4       Door torsional rigidity:

This test, following the procedure ‘01.03-C-439’ and ‘01.03-L-439’ for simulation and physical respectively, is to simulation with the door structure meets the min requirements of twisting and deformation set by ‘FS-0090’. The door is constrained at three points, being the two hinges and the latch and rotated around its axis. The purpose is to identify whether the door can withhold any deformation with a rotation for structural and safety purposes.

6.2.1.5       Side door drop req.:

This test, following the procedure ‘01.03-C-411’ and ‘TPJLR.01.167’ for simulation and physical testing respectively, is used to evaluate that the door meets the requirements set by ‘FS-7000’, for the door drop be less than 15 mm with an abusive weight application of 1000N in its fully trimmed condition. The testing is to verify that the door is strong enough to withhold a certain weight application during its use and does not drop under that abuse. The drop of the door structure can lead to misalignment of the latch and the striker and therefore can lead to overall poor quality of the vehicle and additionally give off a poor optical design graphic/language of the car.

6.2.1.6       Side door sag req.:

This test, following the procedure ‘01.03-L-437’ and ‘TPJLR.01.0169’ for simulation and physical respectively, is used to evaluate that the door meets the requirements set by ‘FS-7001’, for door sag under its own weight in its BiW condition. If the door is not strong enough to withhold the drop under its own weight, usually at the rear edge of a door, can lead to misalignment of the latch and the striker and therefore can lead to overall poor quality. Additionally there would be miss-alignment of the design graphic/language of the car.

CAE Requirement Requirement ID Measure Target Description:
(Door) Window frame lateral rigidity FS-0065 (replaced by FS – 7019) mm Front < 3.5, < 0.5 Pset

Rear < 4.25, < 0.5 Pset

Frame Stiffness/Deflection
Door belt static strength (compressive) FS – 0067 mm <5.1 Strength of door belt
Door belt static strength (expansive) FS – 0067 mm <5.1 Strength of door belt
Door full open overload strength FS-0089 Deg/mm
  • <2 mm Pset in Z at Latch
  • < 1 mm Top and Bot. edge twist.

500N – SUV

400N – Car

Door Torsional rigidity FS – 0090 mm < 4
Side door drop req. FS-7000 mm <12.75, <1.3 Pset Door Body in White & Trimmed Door vertical deflection on vehicles.
Side door sag req. FS – 7001 mm < 1.8 Door Body in White & Trimmed Door vertical deflection on vehicles.

Table 1: Jaguar Land Rover – Side Door CAE Req.

6.2.2        CAE Process:

To gain a better understanding of the door constructions performance under certain circumstances and conditions’ and ‘how the doors performance to the above stated requirements/standards’, simulations (CAE) are set up. CAE allows the engineers to evaluate the performance of a component or an assembly of components under the required conditions and make adequate and/or make necessary improvements. The CAD model is simulated using specific tools/software e.g. Abaqus that allows the simulations of real life conditions, without the actual physical components having to be produced. This reduces the overall costs and allows a much quicker response and fine tuning if components do not meet the expected requirements.

The following CAE tests are associated with the following simulation test procedures at Jaguar Land Rover for Side Doors:

Requirement: Test: Test Procedure:
FS – 7019 Window frame lateral rigidity TPJLR.01.188
FS – 0067 Door belt static strength 01.03-C-402
FS – 0089 Door full open overload strength 01.03-L-441
FS – 0090 Door torsional rigidity 01.03-L-439
FS – 7000 Side door drop requirement TPJLR.01.166
FS – 7001 Side door sag requirement TPJLR.01.168

Table 2: CAE Test requirements/procedures

6.2.2.1       CAE testing process:

For each of the different ‘load-cases/requirements’ a simulation model is set up according to the stated procedure, which dictates a step by step description of what the applied load cases for the specific test are and how the simulation model needs to be set up. The ‘Test procedure’ also highlights/discusses other areas such as test equipment/software and/or the related documents which are inter connected to this specific test procedure. For example: The follow up physical test of this testing.

6.2.2.1.1      Tests:
6.2.2.1.1.1     Door window frame lateral rigidity:

This specific test procedure is applicable to all JLR vehicles side door systems and the objective of this simulation, is to measure the potential deformation and permanent set of door window frame at the top edge of the door frame. It is tested to verify whether the door frame will withstand door seal loads and aerodynamic loads. During high speeds of the vehicle, the generated forces can pull the door frame outboard if the frame is not strong enough. This can cause a degradation of the inner cabin through higher wind and road noises as well as problems with water management along the car and/or to actual leakage into the cabin. This is to be prevented. The Simulation should be carried out in such a way that the top section (load application) of the window frame is parallel to the ground. (See figure 7) The CAE model includes the BiW door module, the hinges, as well as two rigid beams. These are to simulate the transducer mounting bars in the physical test model, which are there for measuring the relative displacement measurement. These are to be kept straight and parallel to each other.

Figure 11: Positioning of door in simulation

The red lines seen in Figure 8 indicate the transducer bars, which are to be located at the front and rear corner of the door respectively, to which they are modelled at a 50 mm offset. The transducer bars are to be attached at two locations on the inner panel, where one is close to the waist area and the other is closer to the lower edge of the door. The door itself should experience the same constrains as it would when positioned in an actual vehicle. In order to simulate this accordingly the hinges are constrained in all ‘Degrees of Freedom’ (DOF), while the door should be allowed to rotate freely around the hinge centre pin. Additionally, the latch will be constrained in the location of 2, 3, 5 and 6 of DOF (Y| – Direction, Rotation in Y, Z – Direction, and Rotation in Z).

Figure 12: Door constraints

During the simulation a specific load application sequence onto the frame needs to be followed.  In the first instance a ‘Gravity Load’ must be applied in a linear direction over a step time of 1.0 second. In order to simulated the deflection of the frame, a load of 180N is applied in a downwards direction in global ‘Z’ at the middle section of either the front or rear corners of the window frame (Front and Rear corner loading test sequence are run separately). This load is then taken off again and replaced with a 360 N load application, applied in global ‘Z’ direction in order to simulate the permanent set of the frame structure.

Load Cases
1. Gravity load
2. Gravity + 180N Front load (Deflection)
3. Gravity + 180N Rear load (Deflection)
4. Gravity + 360N Front load (Permanent Set)*
5. Gravity + 360N Rear load (Permanent Set)*

Table 3: Load case application for ‘Door window frame lateral rigidity’ simulation

During this process a measurement is taken of the relative displacement in ‘Z’ between the transducer bar tip and a measurement point, which is located 25 to 30 mm away from the actual load point. An acceptable result criteria is a deflection of the frame of less than 3.5 mm for the front corner and less than 4.25 mm for the rear corner with less than 0.5 mm permanent set in both instances.

Figure 13: Measurement point application

6.2.2.1.1.2     Door belt static strength (compressive/expansive):

This test is to measure the overall stiffness and rigidity of the belt waist-line of the door, which is important for the structural integrity of the overall door and helps with the performance of the door during a side-crash and therefore with the overall performance of the vehicle. The simulation set up assumes the door to be in a closed position. As in the other test simulations, the hinges are constrained in all degrees of freedom (DOF), while the hinge beam should allow the door to freely rotate around the pin. As an additional constraint, the latch will be constrained in 2, 3, 5 and 6 DOF (Y – Direction, Rotation in Y, Z – Direction, and Rotation in Z). A pair of point loads are applied ‘Normal to Flange’ representing one compressive and one expansive load. For the compressive load, an equal and opposite load of 180N is applied to door waist inner and door outer respectively at 50 mm away from the mid-point in the forward direction of car-line. For the expansive load, the same load is applied for the same points but in the opposite direction.

Figure 14: Load case set-up (FS-0067)

During the loading process, the displacement of the waist, is measured in the local co-ordinate system in the direction of application of the load. The total sum of this displacement gives the change in belt opening width. (W – Inner belt deflection plus outer belt deflection).  For both cases the requirements states a displacement of less than 5.1 mm is acceptable.

Figure 15: Results measurement detail (FS-0067)

6.2.2.1.1.3     Door full open overload strength:

Simulating the effects of the door being in its fully open position and being pushed further open by an external load. This situation can occurs when opening the door on a hill and the door opening energy pushes the door past its detents or when strong winds forces the door further open. The simulation is run with a fully trimmed door, in order to simulate the full weight of the door. The simulation is carried out with the door being installed to the body-side and the door is rotated along the hinge axis to its maximum opening angle. This is usually 65° for a front door and 70° for a rear door plus a 7° of check-arm and hinge engagement. The nominal angle can vary). A gravitational load plus a load of 400 N (for passenger cars) is applied at the latch area and then taken off again.

Figure 16: Door – Full open overload strength model (rear door)

6.2.2.1.1.4     Door torsional rigidity:

The model used for this test is a BiW door model with a module plate and all its connections in position. The simulation is carried out with the door being in car line. As in the other models the hinges are constrained again in all of its DOF’s and the latch is also constrained in 2, 3, 5 and 6 DOF. (Y| – Direction, Rotation in Y, Z – Direction, and Rotation in Z).  A moment of 271 Nm is applied in the X-direction (Mx) in both positive and negative (+271 Nm torque and -271 Nm torque).

Figure 17: Door- Torsional rigidity (FS-0090)

To gain an understanding of the ‘twist’ of the BiW measurements need to be taken. This is to be done by projecting four corners of the primary seal onto the outer panel of the door and the Y-deflection at those specific locations is measured and recorded.

Figure 18: Measurement locations

6.2.2.1.1.5     Side door sag/Side door drop:

This test is to simulate the vertical stiffness of the BiW in order to determine whether the door is capable of not just supporting its own weight at a fully trimmed level but also the weight of a customer supporting themselves onto the door during entry and exit. Any deformation (dropping/sagging) of the door can lead to misalignment of the structure, more specifically of the latch and striker. This can lead to a dramatic increase of door efforts. The complete model includes a fully trimmed door with a module plate, door hinges, BiW section with the pillar structure, the structure connecting pillar into the roof structure as well as the rocker and shot-gun joints. This can lead to a dramatic increase of door efforts. The complete model includes a fully trimmed door with a module plate, door hinges, BiW section with the pillar structure, the structure connecting pillar into the roof structure as well as the rocker and shot-gun joints. The requirement dictates that the vertical deflection of a fully trimmed door on a body-side does not exceed 15 mm elastic and 1.5 mm permanent set when a load of 1000 N downwards is applied at the latch.

In the simulation set-up the body-side is constrained in all 6 DOF’s at the cut edges while the door is only constrained in the Y-Direction. It is important to remember that the constraints should be far enough from the hinges to avoid a significant influence of the constraints on the stress/strain level around the hinges. For the simulation, three individual load cases will tested. These cases will be Case 1, a untrimmed BiW door drop in an ajar (10°) position, Case 2, a fully trimmed door drop also in an ajar position (10°) and Case 3, a fully trimmed door drop in a full open (65°) position.

Figure 19: Door sag/drop CAE model set up (FS – 7000)

The results of door sag and drop will be measured at a specific point which is located 5 mm away from the latch. The first step of each case is to load the door into its position and measure the effect of gravity (sag). After the measurement is taken, a Gravity Load should be applied linearly across a step time of 1.0 sec. A point load of 1000 N should be applied at the latch during a step time of 2.0 sec. The load amplitude should reach its maximum value of 1000 N at the step time of 1.0 sec and should return to a value of 0 N at the step time of 2.0 sec

Figure 20: Measurement point application (FS – 7000)

6.3        Physical:

6.3.1        Physical requirements/standards:

Theoretically after the CAE modelling and testing has been completed and all the necessary changes to the part/system have been made, the physical testing is conducted on prototype components. This is to see whether the CAE results correlate with reality and if those components perform as expected. Typically, the physical components are tested to the same or at least similar requirements and standards used for the CAE simulations. In the case of this project, a conventional steel sash door construction with ‘Resistance Spot Welds’ (RSW) from an Evoque (L538) and a conventional steel sash door construction with ‘Remote Laser Welds’ (RLW) were run through the same, identified tests, and then compared to each other.

These following physical tests are associated with the following standard procedures at Jaguar Land Rover for side doors:

Requirement: Test: Test Procedure:
FS – 7019 Door window frame lateral rigidity TPJLR.01.189
FS – 0067 Door belt static strength 01.03-C-402
FS – 0089 Door full open overload strength 01.03-L-441
FS – 0090 Door torsional rigidity 01.03-L-439
FS – 7000 Side door drop requirement TPJLR.01.167
FS – 7001 Side door sag requirement TPJLR.01.169

Table 4: Physical test requirements/procedures

6.3.1.1       Physical testing process:

6.3.1.1.1      Tests:
6.3.1.1.1.1     Door window frame lateral rigidity:

The test is run to measure the deformation and permanent set of a door window frame at the top edge of the door frame and works in conjunction with the test procedure TPJLR.01.189’. The requirement states (FS-7019) that side doors with a frame shall not exceed a maximum deflection of 4.0 mm at the A-Post, 5.0 mm at the B-Post and 8.0 mm at the C-Post when applying a constant load of 180N at a time. Permanent set shall not exceed 1.5 mm after the application of a 360N load at the same locations. The test was first run with the RLW door and then repeated with the RSP door.

The following method was applied when testing the two door systems:

  1. The ‘Remote Laser Welded’ front door was attached to the test rig by the door hinges as shown:

Figure 21: Side door in testing rig

  1. A bar was attached to the latch and supported in a ‘V block’

Figure 22: RLW latch support

  1. Two bars were attached to the door to support transducers to measure the displacement relative to the door. The module plate was then screwed in to the main body panel.

Figure 23: Transducer bar test set-up

  1. The loading-frame was set-up around the upper frame for the front and rear corner respectively, with load application in the sequence as dictated in the test procedure.

Figure 24: Front/Rear door load application

  1. The same process was then repeated with a RLW door and the results recorded.

Figure 25: RSW doors set up

6.3.1.1.1.2     Door belt static strength:

This test was conducted to test the static strength of the waist belt area of the two doors in accordance to the testing procedure 01.03-C-402’. According to the requirement ‘FS – 0067’ the waist belt opening should not deflect more than 6.0 mm when a compressive and expansive force of 180 N is applied to a specific area. This is to be conducted on an untrimmed BiW door and was first conducted on a conventional door and repeated on the RLW door.

The following method was applied when testing the two door systems:

  1. The door system was stripped of its components except for the hinge systems and the module plate and was then attached to the rig system.

Figure 26: Rig attachment

  1. The door was then secured down on the frame using the torsion bar attached to the latch.

Figure 27: Torsional applicator (FS – 0067)

  1. The rig was set-up for the compression test, where the load was applied in stages of 44N (22N on either side of the belt) to a maximum load of 220N. One the max load was reached, it was taken off again and returned down to 0N.
  1. The rig was then set-up for an expansive load test, where the load was again applied in stages of 44N to a maximum load of 220N.
  2. Both tests were then repeated on the RLW door system and the results were recorded accordingly.

Figure 28: Belt static test: compressive/expansive load rig

6.3.1.1.1.3     Door full open overload strength:

This test is conducted to verify the door system functionality after an overload occurrence of the door when in a fully open position. This usually means a full opening angle (for the front door usually 65° and 70° for the rear) plus the hinge system and check arm engagement stops (+7° usually). The door system needs to be able to withstand an outward horizontal force of 400 N, which is applied to the inner panel roughly at the height of the latch.

The following method was applied when testing the two door systems:

  1. The testing set-up was prepared by mounting the door system and the checkarm system to a hinge bracket which is mountain to a test stanchion that was in turn bolted to the test bed. The door was positioned in its full open position while a hydraulic ram (1), instrumented with a calibrated load cell and attached to a separated stanchion (2) was lined up perpendicular to the door inner face at the same height as the latch. The load cell had a 75 mm spreader plate attached to it. (3)

Figure 29: Door overload test rig

  1. A datum point needs to be determined before the test can be started. In this case, as the test was conducted on a rigid bed, the latch interface point in the close position was agreed as a reference point and used to calculated angle of door rotation.
  2. The door was then rotated to its full open position (65°)
  1. A load of 22N is applied to the door system and a measurement was taken by measuring the angle from datum point to new latch position.
  1. An over-load of 400N was applied to the door system and again a measurement is taken between the two reference points.
  1. The load was then again lowered to 22N and another measurement was taken. Load was removed.
  1. The test was then repeated with the RLW door system.
6.3.1.1.1.4     Door torsional rigidity:

This test is conducted to test the torsional rigidity of a side door and to verify its functionality after the system has been exposed to a torque of 271 Nm in either direction. This is to simulate the stress and force exposure on the system during a crash scenario. This was achieved by fixing the door system to a rig by the hinge system and twisting the door system via a ‘torsion applicator’ in either X+ or X-. The displacement between various points across the door was then measured to see the effect on the door.

The following method was applied when testing the two door systems:

  1. A BiW door system was attached to the rig system by its two hinges.

Figure 30: Door torsional rig

  1. The torsion applicator was attached to the door using a hex bar and socket.

Figure 31: Torsion Applicator

  1. The module plate was fixed into the door system
  1. In order to measure the twist or any movement within the door two transducers where positioned along the belt line of the door, as well as at the bottom of the door.

Figure 32: Transducer application

  1. The inboard torsion load cycle was applied to the door and the door was then loaded in increments of 34 Nm to a maximum torque of 271 Nm, while returning to 0 Nm in between each load stage.
  1. This was then repeated with the RLW door.
6.3.1.1.1.5     Side door sag/Side door drop:

There are two parts to the test, door sag and door drop. The Sag test is conducted to verify whether the door sags under its own untrimmed and trimmed weight no more than 1.0 mm. The Drop test is conducted to verify the functionality of the side door after a force of a 1000N is applied at the latch area at the rear side of the door. This is to ensure that there is no miss alignment between the striker on the body-side and the latch on the door and that the vertical deflection of the fully trimmed door does not exceed 15 mm elastic and 1.5 mm permanent set. Miss-alignment can cause the door closing efforts to increase and degrade the Perceived Quality’ (PQ) of the vehicle. These test should be conducted once at a 10̒° ajar angle and a full open angle, but should be noted that the same door sample should not be used for the same test.

The following method was applied when testing the two door systems:

Sag:

  1. Centre of Gravity (COG) of the door needs to be determined.
  1. The door sample was fitted to a bespoke bracket via the hinges and the door check-arm, which in turn was fitted to a fixed test rig.
  1. Two loaded roller bearers were fitted to independent stanchions on either side of the door. These roller bearers act as a lateral restraint for the door assembly as well as keeps the door in the first test angle (+10°)
  1. In order to measure the vertical displacement of the door, two ‘linear variable displacement transducers’ (LVDT) were positioned. One at the latch and the other at the rear edge of the door.
  1. Using a scissor jack, equipped with a calibrated load cell which is positioned at the bottom edge of the door at the same level as the COG,  (It is to be noted that the COG changes between BiW and fully trimmed door), a force was applied that equates to the actual door mass.

Figure 33: Door sag test rig set-up

Drop:

  1. A hydraulic arm, fitted with a calibrated load cell, is attached with a bespoke load bracket to the door latch and vertically fixed to the testing bed.
  1. In increments of 100N a load is applied to the door until a maximum load of a 1000 N is achieved. (After each increment the load is taken off and returned to 0 N)
  1. The test was repeated with the other door system.

Figure 34: Door drop test rig set-up

6.4        Results:

6.4.1        CAE Results:

Figure 35: CAE test case results

6.4.2        Physical Results:

6.4.2.1       Door window frame lateral rigidity:

Door: Load applied: A – Post: (Front Corner) B – Post: (Rear Corner)
X Deflection: Permanent: Deflection: Permanent:
RSW 360 N 3.275 0.241 3.569 0.797
RLW 360 N 4.007 0.284 3.898 0.334

Table 5: Door window frame lateral rigidity results

6.4.2.2       Door belt static strength:

Door: Load: Compressive: (mm) Expansive: (mm)
RSW: 180 N 1.421 1.701
RLW: 180 N 1.780 1.762

Figure 36: Door belt static strength result

6.4.2.3       Door full open overload strength:

Door: Deflection @ 22N (mm) Deflection @ 400N (mm) Deflection @ 22 N (mm) Permanent Set: (mm) D3 (mm) Door Rotation (°)
RSW: 975 1052 983 8 1010 4.36
RLW: 971 1048 976 5 1010 4.36

D1 = initial distance (22N)

D2 = distance at load (400N)

D3 = distance from hinge pin to edge of door

Door Rotation = DEGREES (SIN ((D2-D1)/D3))

Note: When the test sample was inspected after the test, there were no signs of failure on both door systems.

6.4.2.4       Door torsional rigidity:

Door: Torque direction: Measurement location: Max deflection (mm): Torque: (Nm)
RSW Front 1.43 406.34
RSW Inboard Rear 0.793 271.19
RSW Outboard Rear 1.341 271.02
 
RLW Front 2.284 406.54
RLW Inboard Rear 1.538 271.48
RLW Outboard Rear 1.596 271.69

Figure 37: Door torsional rigidity test results

6.4.2.5       Side door sag/Side door drop:

 

Sag:

 

Based on Mass of Door: Deflection (mm)
Door untrimmed: Door Edge Location: Latch Location:
RSW 0.59 0.58
RLW 0.67 0.53

Table 6: Door sag – untrimmed – results

Based on Mass of Door: Deflection (mm)
Door trimmed: Door Edge Location: Latch Location:
RSW 1.06 1.01
RLW 1.17 0.93

Table 7: Door sag – trimmed – results

Drop:

Load (N):  Elastic Deflection: Permanent Set: 
  RSW: RLW: RSW: RLW:
0-100 0.41 0.32 0.01 0.10
0-200 0.88 0.78 0.02 0.19
0-300 1.42 1.31 0.08 0.22
0-400 2.03 1.81 0.15 0.28
0-500 2.68 2.35 0.22 0.35
0-600 3.32 2.93 0.31 0.39
0-700 3.89 3.53 0.33 0.46
0-800 4.56 4.17 0.45 0.52
0-900 5.21 4.80 0.49 0.58
0-1000 5.91 5.48 0.61 0.66

Table 8: Door drop – trimmed – results

9         Bibliography

1. EWI. EWI – WE MANUFACTURE INNOVATION . [Online] [Cited: 6 1 2017.] https://ewi.org/industries/automotive/.

2. GAO, Paul, et al. Disruptive trends that will transform the auto industry. s.l. : McKinsey Insights, 2016.

3. Pollock, William K. Using Key Performance Indicators (KPIs) to Measure and Track the Success of Your Services Operation. [Online] TNT Online , 2017. [Cited: 25 01 2017.] http://www.s4growth.com/publications/articles/28.cfm.

4. Vincentz Network. Automotive Circle . [Online] 2017. [Cited: 13 02 2017.] http://www.automotive-circle.com/Review/Doors-and-Closures-in-Car-Body-Engineering-2016.

5. Hamill, Jr. , Jack A. and Wirth, Peter. Laser Welding P/M For Automotive Applications. Detroit : s.n., 1994. p. 1, PDF. SAE Technical Paper 940355.

6. New BMW 7 Series – Door Systems. Kirsch, Alexander and Zimprich, Roland. Bad Nauheim : s.n., 2015.

7. Doors & Closures . Adis, Karl-Heinz. Bad Nauheim  : s.n., 2013.

8. Martin Bea, Ruediger Brockmann, David Havrilla. Remote laser welding in automotive production. Industrial Laser Solutions for Manufacturing . [Online] PennWell Corporation, 2017`. [Cited: 12 03 2017.] http://www.industrial-lasers.com/articles/print/volume-26/issue-5/features/remote-laser-welding-in-automotive-production.html.

9. Robin Warmington/JLR. Aluminium Laser Welded Door . 2015.

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