Monocoque chassis

What is a Chassis?
Different Types of Chassis
Ladder frame chassis
Tubular space frame chassis
Aluminum space frame
ULSAB Monocoque chassis
Back bone frame chassis
Introduction to Monocoque Design
What is Monocoque construction?
Where is this used?
Origin of Monocoque design
History of Monocoque Frame

1. Monocoque Chassis Presented By- MANU P. SOMAN ROLL NO 24

2. C ontents What is a Chassis ? Different Types of Chassis Ladder frame chassis Tubular space frame chassis Aluminum space frame ULSAB Monocoque chassis Back bone frame chassis Introduction to Monocoque Design What is Monocoque construction? Where is this used ? Origin of Monocoque design History of Monocoque Frame

3. What is a Chassis? A ‘vehicle frame’, also known as its chassis, is the main supporting structure of a motor vehicle, to which all other components are attached, comparable to the skeleton of an organism.

4. Different Types of Chassis Ladder frame chassis Tubular space frame chassis Monocoque frame chassis ULSAB M onocoque chassis Back bone frame chassis Aluminium space frame Carbon fibre Monocoque

5. Ladder frame chassis The ladder frame is one of the simplest and oldest of all designs. It consists of two symmetrical beams, rails, or channels running the length of the vehicle, and several transverse cross-members connecting them.

6. Originally seen on almost all vehicles, the ladder frame was gradually phased out on cars in favor of perimeter frames and unitized body construction. This chassis is heavier at the same time than a single body. The chassis does not provide any protection against any side impacts. The vehicles like Mahindra bolero and Tata sumo are build on these chassis. It is also seen on trucks .

7. Tubular space frame chassis As ladder chassis is not strong enough , motor racing engineers developed a 3 dimensional design - Tubular space frame. One of the earliest examples was the post-war Maserati Tipo 61 "Birdcage" racing car.

8. Tubular space frame chassis employs dozens of circular-section tubes, position in different directions to provide mechanical strength against forces from anywhere. These tubes are welded together and forms a very complex structure. For higher strength required by high performance sports cars, tubular space frame chassis usually incorporates a strong structure under both doors , hence result in unusually high door sill and difficult access to the cabin.

9. In the early 50s, Mercedes-Benz created a racing car 300SLR using tubular space frame. This also brought the world the first tubular space frame road car, 300SL Gullwing . Since the sill dramatically reduced the accessibility of cabin , Mercedes had to extend the doors to the roof so that created the " Gullwings ".

10. Since the mid 60s, many high-end sports cars also adopted tubular space frame to enhance the rigidity / weight ratio . S ome of them used space frames for the front and rear structure and made the cabin out of monocoque to cut cost.

11. Aluminium space frame Audi A8 was the first mass production car featuring Aluminium Space Frame (ASF) chassis.

12. ULSAB Monocoque chassis Traditional steel monocoque became heavier . As a result, car makers turned to alternative materials to replace steel, with aluminum . Porsche Engineering Services developed a new kind of steel monocoque technology calls Ultra Light Steel Auto Body ( ULSAB ).

13. Compared with conventional monocoque , Porsche Engineering claimed it is 36% lighter yet over 50% stiffer . Although ULSAB was just announced in early 1998, the Opel Astra and BMW 3-Series have already used it in some parts.

14. Back bone frame chassis Backbone tube chassis is a type of automobile construction chassis that is similar to the body-on-frame design. Instead of a two-dimensional ladder-type structure, it consists of a strong tubular backbone (usually rectangular in cross section) that connects the front and rear suspension attachment areas.

15. The backbone chassis was extensively developed by Hans Ledwinka who used it in greater numbers on the Tatra 11 and subsequent vehicles.

16. Introduction to Monocoque Design Monocoque, meaning 'single shell' in French , is a construction technique that utilizes the external skin to support some or most of the load . Monocoque construction techniques were first used as early as 1912. Today, a modified type of monococque construction called “ unit body” or unibody is very popular.

17. A M onocoque chassis is a structure which integrates body and chassis together to form a composite structure which has better stiffness as well as weight advantage . In a M onocoque chassis the stress generated by the vehicle during motion is being distributed among the structure and does not form localised stress which may have higher value of deformation.

18. Where is this used? This form of chassis is now a days being adopted by various segments of vehicle from its inception in F1 which later was adopted to be used for sports cars and now SUV even. The performance of the structure depends on another important factor i.e., the material used to build the structure.

19. The range of material used are from carbon titanium fibre used in Pagani Huayra to Mahindra XUV 500 where aluminium is used. It depends on the type of vehicle and the required performance specifications.

20. Origin of Monocoque design Monocoque construction originated in the aerospace field. Early airplanes utilized wood or metal frames that created the structural base for everything else to be built upon. This caused the weight of the frame to be a huge issue which led to the development of M onocoque construction techniques.

21. One of the first aircraft to adopt these new construction techniques was the Deperdussin monocoque , built in 1912. This formed a structural shell that acted both as the aerodynamic, outer shell and the main load-bearing component , which greatly reduced the overall weight of the aircraft.

22. History of Monocoque Frame In 1922, the Lancia Lambda was the first production automobile to adopt monocoque construction techniques

23. An aluminum alloy monocoque chassis was first used in the 1962 Lotus 25 Formula 1 race car .

24. In 1992 the McLaren F1 became the first production car with a Carbon-fiber Monocoque .

25. Construction of M onocoque Chassis The one piece chassis is actually made by welding several piece together. The floor-pan , which is the largest piece, and other piece are press-made by big stamping machines. They are spot welded together by robot arms (some even use laser welding)in a stream production line. The whole of the body acts as a load bearing member onto which suspension, engine and transmission is bolted . Reinforcements are provided at different sections like doors, bonnet etc.

26. Benefits of Monocoque Chassis A M onocoque construction is much lighter in comparison. The amount of material that it requires to provide significant strength to the car is much less , therefore from manufacturability point of view, it’s economical to produce . All M onocoque cars can be made lighter with the use of better materials and iterative computer analysis. It offers high fuel efficiency due to the low weight that it can achieve through inherent design that it has.

27. The whole structure is actually an outer shell providing better space efficiency . Monocoque chassis benefit in crash protection because it uses a lot of metals Cheap for mass production .

28. Challenges of Monocoque chassis It has very complex design . Impossible for small volume production . The backbone does not protect side impact or off set crash. The setup cost for tooling is too expensive- big stamping machines and expensive moldings. As there’s no separate structure that provides support, in case of accidental collision, chances of permanently damaging the car are quite high .

29. Advantages of BOF over Monocoque structure Can tackle bad roads better. Much better for off-roading. Repair bills are much less when it comes to damage control after hardcore off-roading. Accident repair is also less because of separate chassis and body .

30. Advantages of Monocoque structure over BOF More light, hence fuel efficient. More safe because of integrated chassis/body. Better handling. Much better in ride comfort.

31. Carbon fibre M onocoque Carbon fiber Monocoque is better than traditional monocoques due to its superior rigidity-to-weight ratio. Cars with Carbon-Fiber body panels include Ferrari 288GTO and Porsche 959 .

32. Reference Bicheno , J. (1998) ‘The Lean Toolbox’ Picsie Books, Buckingham. Bramley , A. Mileham , A Newnes , L Owen, G. (1999) ‘Advances in manufacturing technology’ Professional Engineering Publishing Ltd, Bury St Edmunds & London. Monden , Y. (1993) ‘Toyota Production System‘ Industrial Engineering and Management Press Institute of Industrial Engineers, Norcross, Georgia. Nieuwenhuis , P. & Wells, P. (1997) The Death of Motoring? Storey , J. (1994) New Wave Manufacturing Strategies, London: Paul Chapman

33. THANK YOU & ANY QUESTIONS?