Body Shell

Body Shell


As with other models, the E39 all steel body shell acts as a "safety cage" for passenger protection. The structural rigidity of the body shell was increased using Computer Aided Engineering (CAE) techniques. This allowed key points on the body shell to be reinforced, to increase the rigidity, without significantly adding to the weight. The increase of approximately 20 pounds, in body weight, is more than offset by the use of aluminum components for the suspension. Additionally, the structure was designed throughout for "Laser Welding" techniques that ensure the rigid bonding of the body shell components.

Another area of focus in the design of the E39 body was in "Structural Dynamics", or the frequencies at which the body shell normally vibrates. The BMW engineers were able to design the body so that the frequencies for torsional twisting and bending are in an inaudible range.

These frequencies are also out of the range where they will not pick up and amplify engine and driveline vibrations.

The tubular impact structures continue to be a part of the body structure for reducing the amount of damage during frontal or rear impacts.