Design and Analysis of Composite Structures for Automotive Applications

7Dynamics of a Vehicle With Flexible, Anisotropic Structural Elements of Chassis

7.1 Effects of Body and Chassis Elasticity on Vehicle Dynamics

7.1.1 Influence of Body Stiffness on Vehicle Dynamics

The influence of elasticity on the dynamic of vehicles is explained in detail in Section 32.8 of Mitschke and Wallentowitz (2014). The twist stiffness of the car body is a significant parameter of the vehicle design. It expresses resistance to torque that a body has when an axial twist moment is applied, see Chapter 6 in Heißing et al. (2011). This value is estimated for typical passenger car bodies between 15 and 40 kNm/°.

Bending stiffness refers to a difference in pitch angle between front and rear part of the body. A vehicle body bends when it is accelerated and load transfer occurs. This situation appears during accelerations and decelerations of the car. These effects are the so‐called dive and squat behavior. The recovering of the pitch angle after striking a speed bump is another situation in which bending stiffness plays a role. While designing vehicle bodies it is believed that a high value of twist stiffness will also yield to an adequate bending stiffness value of the body.

Local stiffness refers to the stiffness of the suspension attachment points on the body. For evaluation of local stiffness values and its influence on car dynamics, the following full‐car tests are applied: camber and toe, kinematics and compliance. A force or a torque is applied to the center of the ...