A modular design method on vibration for reshaping a specific eigenmode of the focused subsystem to desired one

Abstract

In modern vehicle development, concurrent modular design, which is a productive manufacturing approach that uses pre-made and interchangeable modules to build vehicles and subsystems, has become mainstream to improve design efficiency and strengthen market responsiveness along with the increasing trend towards electrification and electronic systematization. The achievement of the modular design method is also desired in the design of vibration related to several performances such as durability and noise performance. However, developing the modular design method is a challenging task as the performance is influenced by all the subsystems constituting the whole structure. In this paper, a method for reshaping the eigenmode of only focused subsystem to the desired one is proposed as one of the modular design methods. The formulations to calculate a desired eigenmode shape of the focused subsystem are derived based on the dynamic stiffness matrix-based sub-structuring approach and the perspective of maintaining the relationship of vibration coupling between subsystems, which is constituted of internal forces and the eigenmode vector on coupling region where the forces act. Furthermore, the one-on-one correspondence between the reshaping amount of eigenmode and the dynamic stiffness matrix deviation for the reshaping is built involving the finite element model of the focused subsystem and the boundary conditions by expanding the formulation above. Therefore, reshaping to the desired eigenmode with realizable structural modification is achieved. Finally, this proposed method is applied to a numerical case study to reduce vibration responses by allocating modal strain energy to a focused subsystem from the perspective of increasing damping effect.

Keywords

• structural modification
• modal analysis
• substructuring
• eigenmode
• modular design