????????? ? ?????? ??????????????????BMW ServiceNOTE The information contained in this participant manual is intended for participants of the Aftersales Training. Refer to the relevant “BMW Service“ information for any changes/ supplements to the Technical Data.© 2003 BMW AG München, Germany. Reprints of this manual or its parts require the written approval of BMW AG, München VS-12/Vs-42 MFP-HGK-BRK-0211_updateContentsPage Introduction1 Material2 - Steel2 - Aluminium12 Body structure16 - Bodyshell16 Assemblies17 - Weight-reduced aluminium front end GRAV17 - Side frame and roof20 - Side panel, front26 - Underbody28 - Rear end structure30 GRAV32 - Weight-reduced aluminium front end GRAV32 Assemblies34 - Wheel well34 - Engine support39 - Bulkhead42 Joining techniques46 - Steel joining methods46 - Aluminium joining techniques47 - Steel-aluminium joining techniques49 Crash characteristics50 - Frontal crash50 - Side crash52 - Rear crash54E60 Bodyshell - Expert- 1 -IntroductionThe E60 is the first vehicle to feature a mixed aluminium-steel construction. The front end of the vehicle is made of aluminium with a steel passenger cell and rear end.Thanks to mixed construction and the use of high strength steels, the body weight was reduced to 255 kg (not including doors, bonnet, boot lid and flaps) while weight distribution was improved.The terms aluminium and steel are the generic term for the vast number of alloys used that exhibit a wide variety of different properties.This publication describes in detail the selection of materials and their properties, the design of the body structure, the jointing methods and the crash characteristics of the E60.E60 Bodyshell - Expert- 2 -MaterialA modern car body must satisfy a large number of demanding require- ments. For instance, the interior should be as large as possible in connection with the smallest possible outside dimensions. In the event of an accident, the best possible protection against injuries must be provided for the passengers. All major assemblies such as the engine and gearbox with their high torque forces are supported by the body. In addition, the body must exhibit high static and above all dynamic rigidity in order to guarantee the outstanding driving characteristics so typical of BMW vehicles.Not least, the load bearing structure of the vehicle must exhibit a high degree of fatigue strength and must be repairable with feasible effort and expenditure in the event of an accident.In order to ideally satisfy all these demanding requirements, BMW pursues the strategy of manufacturing each component from the material best suited for its function.- Steel9 different types of alloys are used on the E60. The different properties and application examples are illustrated in the following.The steel grades are distinguished with 3 important characteristic values:- Rp -> yield point in N/mm2- Rm -> tensile strength in N/mm2- A80 -> percentage elongation after fracture in %The characteristic values Rp and Rm are important for the component design with regard to strength, crash properties and thickness. The elongation after fracture A 80 provides a measure for the plasticity of the material in the press plant.E60 Bodyshell - Expert- 3 -Deep-drawn qualities (e.g. DC 05)These standard materials are used for components that do not need to exhibit special strength characteristics such as brackets for instance. However, these materials are also used for components that do not permit the use of higher strength steels due to their complex geometry or high degree of forming.The deep-drawn grades exhibit a yield point range between 120 - 140 N/mm2, a maximum tensile strength of 450 N/mm2and a percentage elongation after fracture A80 of 40%.The standard materials can be welded very effectively with the methods and equipment used as standard in body construction.Further examples are the roof, floor pan and the luggage compartment floor.Fig. 1:Roof outer skin panelKT-11368E60 Bodyshell - Expert- 4 -IF steels (e.g. H 220Y)IF steels are selected for complex formed parts that feature both deep- drawing as well as stretching stress and strain and varying drawing depths.On the whole, these alloys exhibit very low carbon and nitrogen content. They are characterized by excellent cold forming and welding properties.IF steels exhibit a yield point range between 180 - 260 N/mm2, a maximum tensile strength of 440 N/mm2and a percentage elongation after fracture A80 of 32%.Typical applications for IF steels include deep-drawn and stretched parts with different drawing depths such as the side carcass for instance.Fig. 2:Side carcassKT-11369E60 Bodyshell - Expert- 5 -Isotropic grades (H220 I)Components that are predominantly formed in a stretching process are mainly made of isotropic steels.Isotropic grades exhibit a yield point range between 220 - 300 N/mm2, a maximum tensile strength of 440 N/mm2and a percentage elongation after fracture A80 of 36%.Isotropic steels can be welded and brazed usi。