Masters thesis of design mission impossible design manufacture of a solar car that appeals to the general public

Mission Impossible: Design & Manufacture of A Solar Car That Appeals To The General Public A Project submitted in fulfilment of the requirements for the degree of Masters of Design Matthew Millar Bachelor of Industrial Design (Honours) Honours 1st Class, RMIT School of Design College of Design and Social Context RMIT University October 2020 Declaration I certify that except where due acknowledgement has been made, this research is that of the author alone; the content of this research submission is the result of work which has been carried out since the official commencement date of the approved research program; any editorial work, paid or unpaid, carried out by a third party is acknowledged; and, ethics procedures and guidelines have been followed In addition, I certify that this submission contains no material previously submitted for award of any qualification at any other university or institution, unless approved for a joint-award with another institution, and acknowledge that no part of this work will, in the future, be used in a submission in my name, for any other qualification in any university or other tertiary institution without the prior approval of the University, and where applicable, any partner institution responsible for the jointaward of this degree I acknowledge that copyright of any published works contained within this thesis resides with the copyright holder(s) of those works I give permission for the digital version of my research submission to be made available on the web, via the University’s digital research repository, unless permission has been granted by the University to restrict access for a period of time I acknowledge the support I have received for my research through the provision of an Australian Government Research Training Program Scholarship Matthew Millar 12th October 2020 Matthew Millar Mission Impossible P a g e | ii Mission Impossible: Design & Manufacture of A Solar Car That Appeals To The General Public Figure 1: Priscilla qualifying lap Matthew Millar Mission Impossible P a g e | iii Acknowledgements This has been a challenging journey, I’d like to acknowledge that I have had a great team of people supporting me through the degree and this project Firstly, I would like to express my gratitude to my supervisor’s beginning with Simon Curlis for his continuous support over the entire solar car campaign From my Industrial Design Honours year, through the strenuous World Solar Challenge design, manufacturing and event, and to the end of this two-year study and research period His patience, motivation, enthusiasm, and immense knowledge has allowed me to achieve what I have so far and has given me confidence in my future career I also appreciate the time, effort and philosophy of Dr Liam Fennessy on the theoretic side of my research The improvement and clarity of my writing have been greatly enhanced by his input and patience I have also benefited vastly from Liam’s guidance throughout each milestone and the entirety of this degree Prof Simon Watkins has also been tremendous support behind the scenes as well as academically I’m extremely grateful for the scholarship Simon offered and organised for me to commence my studies for this amazing experience, and the advice from both an academic and engineering perspective is greatly appreciated I would like to express my gratitude to Andris Samson, for not only passing on his knowledge of solar cars but also being a pleasure to collaborate with during design, manufacture, driver training and throughout the event Without his input and fair compromise to better the team, the car would not have been ready for the challenge I would like to thank the ATN & ATN Solar Car Team, for allowing me to be a part of their exciting project, and offering their knowledge and assistance I may require moving forward The opportunity to design, build and drive a car across Australia was an amazing experience and is one I never thought I would be able to participate in I thank my fellow students/team members/faculty I have received generous support and made great memories throughout the course and on our World Solar Challenge journey To the RMIT staff, David Carletti, Paul Muskat, and all other technical staff Thank you for all their support and efforts to provide us with everything we needed and made it possible for us to build a car in such a short time frame I gratefully acknowledge the assistance of Michael Bodon, for helping me grow into a management role, and learn from his experience in composites and other manufacturing methods Michael was also a great asset to the team from a management perspective, hands-on in the workshop, and providing external services to assist us with completing the car at a high level of quality Thanks to my fellow team members, in particular, Richie Hongladaromp and Philip Ngan for providing brilliant photography through the build process and event And last but not least I am deeply grateful for the support of my family, who have been greatly tolerant and patient with me through my time at RMIT and continue to offer much-needed support all year round Matthew Millar Mission Impossible P a g e | iv Figure 2: Solar cells Matthew Millar Mission Impossible Page |v Table of Contents Declaration ii Mission Impossible: iii Acknowledgements iv List of Figures xi List of Tables xiv Acronyms xiv Abstract Chapter 1: Solar Car Design & Aesthetics Introduction Chapter Introduction Research Approach Solar Electric vehicles Competition - Design/Engineering Sustainability Vehicle Styling Action Research World Solar Challenge 10 Cruiser Class 10 11 Event 11 Car design aesthetics 14 Car Design Characteristics and Strategies 16 Aerodynamics 24 Composites 26 Solar Car Analysis - Aesthetics concerned by proportionate elements 27 WSC Cruiser Class Judging Criteria 35 37 Chapter 2: Design Process 37 Chapter Introduction 38 Exterior Design, Capturing eyeballs 38 Collaboration with Engineers to meet performance criteria 39 Integration & FEA Engineering 44 Headlights 45 Matthew Millar Mission Impossible P a g e | vi Exterior Aesthetic 48 Interior Design 51 Concept Sketches 51 Colour & Trim 52 CAD Modelling 53 Steering Wheel 54 Interior Validation and Re-designing from the Inside-Out 57 Ingress & Egress 57 Seating position 59 Doors & Windows 60 Dash and Console 60 Steering and pedals 61 Simulation 61 Dynamic Test Rig 63 Chapter 3: Design in the process of fabricating a Solar Car 64 Chapter Introduction 65 Engagement with Industry production and fabricators 65 Tool Making 65 Vehicle Manufacturing – Chassis & Exterior 67 Bulkheads & Wheel Wells 67 Lower Chassis 68 69 Upper Chassis & Doors 69 71 Windows 71 Headlights 71 Vehicle Manufacturing – Interior 72 Dash, Centre Console, Door trims 72 Steering Wheel 72 Seats 73 Vehicle Assembly & Integration stage – Body & Structure 73 Trimming & Dry Fitting 73 Upper & lower chassis bonding 74 Carbon heat treating 75 Door Trimming and bonding 76 Matthew Millar Mission Impossible P a g e | vii Exterior finishing Stage 77 Vehicle Assembly & Integration Stage – Mechanical 78 Suspension, steering, brakes & wheels 78 Seats & Safety Harnesses 80 Door Hinging & Latching 80 Vehicle Assembly & Integration Stage – Interior & Finishing 81 Dashboard, Centre console, door trims & Seats 81 Vehicle Assembly & Integration stage – Lighting & Windows 83 Lights 83 Windscreen & side windows 83 Vehicle Assembly & Integration stage – Electrical 84 Vehicle Assembly & Integration Stage – Finalising on the road & at the track 85 Exterior Finishing Stage 89 90 Chapter 4: Validation of the Design 90 Chapter Introduction 91 Vehicle Validation – Performance 91 Static Scrutineering 91 First test drive 92 Gun Point Road testing 92 Dynamic Scrutineering 94 The Event – Darwin to Adelaide 95 Practicality Judging in Adelaide 99 The result 100 Showing the project publicly 101 Chapter 5: Reflections on What I Have Learned 106 Reflection 107 Discussion 108 Conclusion 110 References 112 Appendices 116 Appendix 1: Coupe concept sketch renders 116 Appendix 2: Concept 3: Bird of Prey Concept 118 Appendix 3: Bird of Prey Renders 119 Appendix 4: Bird of Prey Iterations 120 Matthew Millar Mission Impossible P a g e | viii Appendix 5: Concept - Glider 123 Appendix 6: Concept Iterations 123 Appendix 7: Solar car colour/liveries 128 128 Appendix 8: List of instruction for interior CAD redesign 130 Appendix 9: Detailed Test Rig Fabrication & Validation 132 Interior Validation phase 133 Electrical Layout 135 Finalising for Driving 136 Test Driving 136 Appendix 10: Introduction to Carbon Fibre Resin Infusion 139 Appendix 11: Build Team & Industry Experts 143 Appendix 12: Chassis Tool Making – Detailed build log 144 Wheel Wells 144 Lower Chassis Mould 145 Upper chassis0 146 Solar Array and Bulkheads 147 Appendix 13: Interior Tool Making – Detailed build log 147 Dash, Centre Console & Door Trims 147 Seats 148 Appendix 14: Chassis Fabrication – Detailed build log 149 Rear Bulkhead - The official first part 149 Wheel Wells – Mould Preparation, Lay-up & Infusion 149 Front Bulkhead – Mould Preparation, Lay-up & Infusion 151 Lower Body/Chassis Fabrication 152 Datum points 152 Lay-up strategy 152 Upper Doors 160 Upper chassis 162 Solar Array 165 Appendix 15: Interior Manufacturing – Detailed build log 166 Dash, Centre Console, Door trims 166 Steering Wheel 168 Seats 168 Appendix 16: Vehicle Assembly & Integration stage – Body & Structure – Detailed build log 169 Matthew Millar Mission Impossible P a g e | ix Front bulkhead & Wheel wells 171 Upper chassis dry fit 172 Appendix 17: Vehicle Assembly & Integration stage – Mechanical 173 Appendix 18: Vehicle Assembly & Integration stage – Interior & finishing 175 Matthew Millar Mission Impossible Page |x Appendix 14 - Figure 17: Upper door carbon lay-up Appendix 14 - Figure 18: Door infusion Door de-moulding 24 hours later, the doors were cured and were removed from the mould The finished parts didn’t turn out great, both doors had dry spots, inverted valleys, and waved surfaces There could be multiple factors contributing to the failure of these parts including poor resin port location, not enough resin, or loss of vacuum Either way, we had to find a way to resurrect them, as we didn’t have much time or material to re-make them One of the contractors Michael Bodon brought in was an expert composite cutter, and he trimmed both doors and window flanges once I marked out the cut lines They were then sanded smooth and ready to be used for plants Matthew Millar Mission Impossible P a g e | 161 Upper chassis carbon lay-up To prepare the doors to be used as plants, some air weave cotton like material was layered along the A-pillar to create an offset for the door seal The entire door was wrapped in release film like the window templates, to prevent resin smothering the part The upper chassis mould was cleaned and treated again with a release agent, and the doors were positioned into the mould ready for the layup The same lay-up process as the lower chassis and doors was carried out Appendix 14 - Figure 19: Upper chassis windscreen & door plants Appendix 14 – Figure 20: Upper chassis carbon layup & Infusion (Photo Credit – Phillip Ngan (bottom right)) Matthew Millar Mission Impossible P a g e | 162 Upper chassis de-moulding The following day the part was pulled out of the mould, and the result was very positive, with no imperfections to be seen, and a nice gloss finishes from the resin Once the part was out of the mould, the Windscreen template and doors were removed which proved very difficult The Windscreen foam was simply chipped away from the recess of the part, but the doors required several hours of persuasion Unfortunately, the release film on the doors wasn’t effective, and resin flowed around and inside the film, fusing the doors to the upper chassis (Appendix 14 - Fig 21 left) To remove them, Myself and Michael Bodon used hammers and chisels to carefully yet forcefully separate the three bodies Some areas of the resin cracked in the form with the chassis, but others did not, requiring precision carving away The chisels and scrapers were wedged between the door and body and hammered around the entire door line Once most of the doors were separated, more calculated force and levering eventually cracked the doors off the upper chassis The finish of the inner door flange was quite rough as a result, and some areas of resin had chipped away leaving small imperfection of A-class surface surrounding the door (Appendix 14 - Fig 21 right) Appendix 14 - Figure 21: Upper door fused to upper chassis (Left) Upper chassis door recess (right) Following the door removal, all the film was stripped from the doors, and the resin had actually fixed some poor surface area However, the resin layer was fairly thick, and there were still some Valleys, which required further repair Repairs As the upper chassis was in great shape when it came out of the mould, the only repairs required were the doors Michael Bodon suggested we sand away the thick layers of resin, and perform a resin wipe over the top to bring back the smooth shiny surface as well as filling any wavy dents So, we each took a door, where further several hours were spent trying to perfect the surface I began with grinding the excess resin which had built up inside the window flange, this was a very delicate procedure because the air-powered sander stripped away resin very effectively, and could easily bite into the carbon layers behind the resin Then, I created tacky tape walls around the wavy and dented areas, then filled them with a quick set epoxy resin Once the resin dried, the tacky tape was removed, and the now raised areas were sanded smooth with the existing surface (Appendix 14 Fig 22) Michael carried out the same process on the other door, then we both cleaned the surface with isopropyl then brushed new resin over the entirety of the doors Matthew Millar Mission Impossible P a g e | 163 Appendix 14 - Figure 22: Door resin repair The resin was applied while the door was laying outer surface up, and Michael explained in his experience brushing the resin on, leaves no brush lines, and gravity will allow the resin to spread evenly over the applied surface Unfortunately for an unknown reason and to Michaels surprise, the resin was almost repelled to the surface, and as it was drying, formed shallow spots down to the surface This happened on both doors, and Michael and I thought either fine dust or a reaction to the isopropyl on the surface caused the resin to behave in an unfamiliar way From this point, we discussed how to address the new issue, and came up with the idea of sanding the resin back again, but applying a clear coat acrylic paint to simulate the resins gloss finish So, using a scrap carbon fibre piece, I sanded the gloss finish away to a dull carbon finish, cleaned with isopropyl and sprayed acrylic clear coat (Appendix 14 - Fig 23) After approximately 10 minutes the paint was touch dry and resembled the gloss resin really well, and the sample piece validated our next step Michael and I tackled the doors again, this time sanding them smooth (Appendix 14 - Fig 24), and then they were taken to the spray booth were layers of acrylic clear coat were applied Once fully dried, the doors appeared faultless, apart from very few minor imperfections, and were ready to assemble to the lower part of the door Appendix 14 - Figure 23: Acrylic clear coat sprayed on sanded carbon fibre Matthew Millar Mission Impossible P a g e | 164 Appendix 14 - Figure 24: Upper door sanded carbon/prep for acrylic coat Solar Array The Solar array was created slightly differently to the other MDF moulded parts The mould itself was primed and painted like the others, but prior to the carbon lay-up, the entire mould was coated in release film, as the surface finish didn’t have to be perfectly smooth With a suggestion from Paul Muscat, the team decided to carry out a wet layup instead of infusion This process still used the vacuum bag to pressurise and compact the carbon to the mould but wasn’t reliant of evenly spreading resin through the part as it was applied by hand pre-bagging This part was also made with a combination of carbon fibre and fibreglass, with a series of structural foam core ribs The ribs were bonded to the underside of the array once the first wet lay-up was completed Following the completion of the structure, the solar cells were integrated using double-sided tape, and the wiring for each sheet of cells was threaded through a series of holes The array was then fitted to a wooden frame, and the wiring was routed to minimise the number of cables and to avoid any potential damage during opening and closing Appendix 14 - Figure 25: Solar array construction (left) Solar cell fitment (Right) Photo Credit – Yianni Pappas Matthew Millar Mission Impossible P a g e | 165 Appendix 14 - Figure 26: Solar array wiring (Photo Credit – Phillip Ngan) Appendix 15: Interior Manufacturing – Detailed build log Dash, Centre Console, Door trims Following the strenuous sanding of the polystyrene moulds, the same process as the MDF moulds was performed in preparation for the carbon lay-up The PVA release agent was applied to all three moulds, and to speed up manufacturing with advice from Paul Muscat, we decided to a wet layup with no vacuum bagging Richie began with the door trims, with a combination of carbon fibre and fibreglass, as the fibreglass fabric was much more flexible than the carbon, and worked into tight radii easier I and Andris began to make the dashboard, by using carbon fibre for the front facia of the dash, and plies of fibreglass for the remaining surfaces Some chop strand fibreglass was also used in tight radii because the fabric simply couldn’t contour to every edge The wet lay-up began with mixing resin, and brushing an even coat inside the mould, then laying in the fabric It was a tricky process and was made easier with two people handling the material While laying the fabric, we used the brush to manipulate the fabric into corners and cut splices in various areas to help the material nest into the mould Once each layer of material is laid, more resin is brushed across the entire fabric, with the aim to “wet” the entire area Appendix 15 - Figure 1: Dashboard carbon fibre & fibreglass wet lay-up Matthew Millar Mission Impossible P a g e | 166 The centre console was constructed in the same manner as the dash, but much simpler due to there being less intricate details The only difference between the lay-up is that the dash was mostly fibreglass because of its complexity, and the console was plies of Carbon fibre Centre console carbon fibre wet lay-up De-Moulding & Repairing 24 hours later, each interior component was removed from the mould and placed in a curing oven at around 60 degrees Celsius Following the final step of curing, myself, Richie and Andris spent many hours sanding the imperfections left from the mould that we couldn’t fix pre lay-up One of the dramas which occurred during the sanding is that door trims were only made with only plies of carbon, and sanding away the bumps eventually wore all the way through the material leaving holes to repair To repair the holes, automotive body filler was used and various spots around the door trim The Dash and centre console only required a small amount of filler, to smooth to imperfections from the carbon lay-up After the filling and sanding, each component was ready to be test fitted, then finished for final assembly Matthew Millar Mission Impossible P a g e | 167 Appendix 15 - Figure 3: Door trim, Centre console & Dash post repair & trimming (Photo credit – Richie Hongladaromp Steering Wheel The outer casing was printed at the RMIT AMP building, and once it arrived at the workshop, the outer surface was rubbed with acetone and sanded to eliminate the fine 3D print grooves The inside of the front face had thread holes for the rear casing fasteners, however, we decided to drill them out and glue in nuts, as they would be much more secure than a plastic thread Pictured below is the carbon and Kevlar composite structural plate of the steering wheel Appendix 15 - Figure 4: 3D print steering wheel casing & 1st iteration Carbon/Kevlar composite structural plate (Photo Credit – Richie Hongladaromp) Seats Both the backrest and base of the seat was fabricated by build team members Alwin, Alvin and Phillip The first step was to form sheets of 4mm foam core around the mould using heat lamps to soften the material, while slowly increasing vacuum bag pressure so it would conform to the seatback mould shape This was done prior to the lay-up because if the foam wasn’t preformed it could split, or disturb the carbon plies while under vacuum The infusion was then carried out, using Matthew Millar Mission Impossible P a g e | 168 release film on the mould instead of release agents, as the surface finish didn’t need to be a gloss finish This process was used to make two sets of seats Following the infusion and curing time, the seat was then trimmed to the correct seat profile, including seat belt slots Appendix 15 - Figure 5: Seatback foam core (Top left) Seatback trimming (Top Left) Seat base infusion (Bottom Left), Seat base infusion & final part (Bottom Right): Photo Credit – Richie Hongladaromp Appendix 16: Vehicle Assembly & Integration stage – Body & Structure – Detailed build log Middle, Rear & Tail bulkheads With the chassis and other components manufactured, planning for assembly and integration began The lower chassis is possibly the most important part, as almost every structural and mechanical component is directly attached or reliant of it The lower chassis was placed back into the mould, so we could use the datum points to mark out where bulkhead, doors, and seating positions onto the part Michael Boden’s colleague was available to assist us with trimming the carbon fibre parts, which began with the flange of the lower chassis The flange was trimmed down to 50mm of width, and 20mm slots were cut on each side for the rear and middle bulkheads to drop into Profiles from the CAD were traced onto each bulkhead and were trimmed and test fitted to the lower chassis Several adjustments were made to ensure the bulkhead fit as cleanly as possible to the contours of the floor Appendix 16 - Fig 1) The upper chassis flange received the same treatment as the lower chassis, and the bulkheads were slotted in and iteratively trimmed until they matched the roof Matthew Millar Mission Impossible P a g e | 169 curvature The tail bulkhead was also trimmed to fit the lower chassis, but not the upper chassis as the solar array closed over the top of it Each bulkhead was then removed and had holes drilled and bushing installed for suspension, solar array hinges & latching mechanisms The holes were aligned using a paper template printed from the data of the CAD Appendix 16 - Figure 1: Rear bulkhead iterative trimming for fitting Wheel doors & wheel spat trimming In order to access the rear suspension and wheels for initial installation and maintenance, the rear wheel spats needed to be removable A paper template was created using the wheel spat split line of the CAD, was traced onto both rear spats and cut out (Appendix 16 - Fig 2) Front-wheel doors also needed to be trimmed, these would open and close when the wheels are turning The outer doors required an MDF template to run the cutting tool around The accuracy of this wheel door size and shape was important because they must perfectly align with the wheel wells Once the outer and inner wheel doors were trimmed from the lower chassis (Appendix 16 - Fig 3), they were sanded to remove any sharp edges or fraying Appendix 16 - Figure 2: Rear-wheel spat trim Matthew Millar Mission Impossible P a g e | 170 Appendix 16 - Figure 3: Front wheel door trim Front bulkhead & Wheel wells As the assembly of the lower chassis gain momentum, the front bulkhead and wheel wells were the next components to be fitted The front bulkhead was to be trimmed to the dimensions of the CAD, but luckily just before that happened, UTS discovered they had made an error of the front wheel track, meaning the wheels and front suspension had to move outboard 26mm, which in turn means the wheel wells needed to move out by the same margin This was beneficial for the ingress & egress and the legroom inside the car Following this correction, the front bulkhead along with the wheel wells was trimmed The wheel wells position was marked on the lower body from the datum points on the mould, then were also iteratively trimmed to fit the floor and wheel spats of the lower chassis Zack McIntyre then created a mounting jig (Appendix 16 - Fig 4) to ensure the wheel wells are perfectly aligned in each direction, and the suspension holes are located correctly These holes were then drilled using part of the jig as a template on the inner face of the wheel wells suspension wall Aluminium bushings were then fitted to avoid the carbon being compressed when the suspension is fitted Then the jig is assembled and the wheel wells are attached The front bulkhead was then aligned and bonded to the wheel wells inner shoulder Appendix 16 - Figure 4: Wheel well assembly jig (Photo Credit – Richie Hongladaromp) Matthew Millar Mission Impossible P a g e | 171 With the Wheel well and front bulkhead assembly bonded and trimmed, it was dropped into the lower chassis and bonded into position with a carbon fibre wet lay over the bonding material to reinforce the structure Upper chassis dry fit With the upper doors removed from the upper chassis, the excess carbon of the windscreen and door flanges were marked, trimmed and finished to leave a flange so that it could be aligned and dry fitted to the lower chassis (Appendix 16 - Fig 5) Appendix 16 - Figure 5: Upper chassis dry fit Matthew Millar Mission Impossible P a g e | 172 Appendix 17: Vehicle Assembly & Integration stage – Mechanical Solar array hinging & locks One of the most difficult components to integrate was the solar array Due to its large size and lightweight, it required thick structural ribs to restrict the amount of flexibility of the part The edges were shaved until they were leaving the smallest consistent gap between the A-C pillars The upper chassis also required trimming to allow for the solar array ribs and hinging arms fit and not intersect during opening and closing (Appendix 17 - Fig 1) This large cut out of the upper chassis was also used to access our luggage compartment and battery Appendix 17 - Figure 1: Upper chassis trimming (Photo credit – Richie Hongladaromp) These structural ribs were also important as they provided a mounting area for the array mechanisms including hinges and a latch The array is supported by sets of hinges, the front set mounts from the middle bulkhead to the front rib, and the rear hinge mounts from the rear bulkhead to the centre rib (Appendix 17 - Fig 2) These hinges were designed to lift the array up slightly before opening to the side, this was to avoid the edge of the array hitting the body Appendix 17 - Figure 2: Solar array hinging (Photo Credit- Anna Lindqvist) Matthew Millar Mission Impossible P a g e | 173 Adjusting the opening angle of the solar array and keeping it in the same position is crucial for obtaining as much solar energy as possible To this, we used telescopic poles in a cross formation from the bulkheads to the structural ribs (Appendix 17 - Fig 3) As the poles extend, there is a simple clamp that can be operated one-handed while supporting the array in the desired position Appendix 17 - Figure 3: Telescopic poles (Photo Credit – Anna Lindqvist) Fully extended, the array is able to open and lock at a 90 degree angle, which would be beneficial when the sun is rising and setting to get solar energy collection at all times of the day Matthew Millar Mission Impossible P a g e | 174 Appendix 18: Vehicle Assembly & Integration stage – Interior & finishing Appendix 18 - Figure 1: Door trim painting (Photo Credit – Richie Hongladaromp) Appendix 18 - Figure 2: Centre Console Switches (left) Compartment (right) (Photo Credit – Richie Hongladaromp) Appendix 18 - Figure 3: Seat cushions (Photo Credit- Richie Hongladaromp Matthew Millar Mission Impossible P a g e | 175