Study on the Influence of Nonlinearity of Bushing and Air Spring Stiffness in Truck Suspension System on Joint Forces and Moments Calculation 2020-01-1395
The joint forces and moments applied to the joints in an air suspension system in truck are important input loads for lightweight and fatigue analysis of bushings, air spring brackets and trailing arms. In order to derive a reliable solution of joint forces and moments, engineers will generally use Multi Body Dynamics (MBD) simulation software, like ADAMS, which can save time in product development cycle. Taking an air suspension in truck as a study example, a 2-dimensional quasi-static model of an air suspension, whose stiffness of air spring and bushing is nonlinear, is established in ADAMS environment. After that, simulations are performed at the typical and extreme working condition, and the results are compared with another two cases. Case I assumes that all components are connected with rigid joints, and the stiffness of air spring is constant. Case II simplifies that all joints are replaced with flexible bushings, and the stiffness of bushings and air springs is constant, and the torsional stiffness of bushing is ignored. The comparisons with case I and case II show that the stiffness nonlinearity of air spring and bushing have a significant effect on the calculation for the joint forces and moments, especially when the vehicle runs in extreme driving conditions.