Engineering Process of a Nonlinear Vibration Isolator on Application for Electric Drive of Commercial Vehicle 2023-01-1062

Engineering of solutions for vibration challenges consists of several steps. Each of them needs different methods, for most steps, several approaches are valid. This work describes an efficient way to get from customer requirements via computational methods, experimental tests and lifetime calculations to a suitable product. The example is a metal cushion molded from wire mesh, used as a spring-damper system. Metal cushions for vibration isolation are used where high dynamic stresses occur or the environmental conditions overwhelm rubber solutions. Progressive nonlinear stress-deflection behavior and the high damping offer advantages for a wide range of applications. Here, a vibration problem in a suspension of an electrical drive is solved. The application is a commercial vehicle that is used in a city cycle. Customer requirements gained from measurements describe the geometrical boundaries as well as the loads and needed isolation frequency for acoustical improvement. Experiments were performed to define the parameters for an analytical equation to describe the nonlinear force-deflection characteristics of metal cushions. The vibration engineered design of the cushions is validated with quasi static measurements. The nonlinear properties are linearized in the working point during vibration stress. In the last step, the achievable lifetime of the cushions needs to be examined. Here, the comparison of the load, out of calculated or measured results with the fatigue strength leads to reliable estimation of the fatigue lifetime. Cushions specific S-N curves are available. The work will show the whole development process on the example of an electrical drive in a commercial vehicle. Experiences and best practices from day to day work will be shared to discuss and improve the development process for NVH issues on body structures.