Design And Development Of Random Vibration Pseudo-Excitation Method Module Based On SiPESC Platform

In actual engineering situation such as vehicle NVH, structural anti-seismic, the vibration feature cannot be evaluated by deterministic function but probability and statistical methods. This kind of vibration is called random vibration. Although traditional vibration theory has been widely adopted, it cannot be applied to solve random vibration problem in engineering. Nowadays, the amenity of transportation vehicle and security of building structure have higher and higher standard and these needs make random vibration theory and algorithm based on random load and PSD-function a research hotpot.Within many mature algorithms, the Pseudo-Excitation method proposed by Prof. Lin J H in Dalian University of Technology is widely accepted in both science and engineering society for its superior calculation efficiency and exceptional precision. The key idea of Pseudo-Excitation method is to decompose load PSD into several pseudo excitation and then the pseudo response of structure is calculated through frequency response or transient analysis. Finally, the structural response PSD can be composed by some simple operations. In this method, the original hard random vibration problem is converted to traditional structural dynamic problems. Unfortunately, the random vibration analysis methods in current commercial CAE software are quite obsolete and the Pseudo-Excitation method has not been implemented. Furthermore, most commercial CAE software cannot analyze non-stationary random vibration problem. In this thesis, a large-scale stationary/non-stationary random vibration analysis software module is designed and developed using Pseudo-Excitation method to face the above problems.In this thesis, a standard format for stationary/non-stationary load PSD input is established first. Using this format, the pseudo excitation generating and response PSD solving process are derived and the calculation module of stationary/non-stationary Pseudo-Excitation method is developed based on SiPESC.FEMS. At the same time, a unified multi load case and multi module calculation framework focused on frequency response and stationary random vibration problem is proposed to accommodate the needs of both normal multi-load case frequency response and stationary Pseudo-Excitation analysis. As for non-stationary situation, a database framework is set up for multi frequency and multi load case transient analysis and a non-stationary Pseudo-Excitation analysis function is implemented based on this framework.Compared with other commercial CAE software, the Pseudo-Excitation analysis module proposed in this thesis is suitable for multi parameter, large-scale random vibration analysis and non-stationary random problem.