Virtual Experimental Modal Analysis Of Railway Car Body

Mode is the mechanism natural vibration characteristic, each mode has the specific natural frequency, the damping ratio and mode shape. This mode parameter may be obtained by the computation or the experimental analysis, this kind of computation or experimental analysis process is called modal analysis. The experimental modal analysis is an important method to distinguish the structure's dynamic performance and design the complex structure, but this method only to be able makes after the structure to carry on, regarding to the large-scale structure such as railway car-body, is very difficult to change its dynamic characteristic once determined, moreover the experiment cost is very high regarding the large-scale complex product. This paper proposes the Virtual Experiment Modal Analysis (VEMA) method, uses virtual prototype model, simulates the exciting signal on the computer, and realizes Virtual Experiment Modal Analysis, thus in the product design stage forecasts structure dynamic characteristic, instructs the design, reduces the local vibration, and also prepares for the physical prototype experiment. This will enhance the product dynamic performance, speed up the product development cycle, and enhance the enterprise competitive ability.This article elaborates the computation modal analysis and the experimental modal analysis theory, unifies the two methods, and proposes the Virtual Experiment Modal Analysis (VEMA) method. The frequency response result of the structure under the exciting signal are obtained through finite element analysis, the Frequency Response Function (FRF) of the measuring point are computed, then the natural frequency, the damping ratio and mode shape are gotten by the parameter recognizing method. Through two examples confirms the feasibility of VEMA. This paper established the railway car body simulation model, carried on the computation modal analysis, and using VEMA method, created the exciting signal, carries on the Virtual Experiment Modal Analysis to the car body, determined the best exciting and response location, analyzed the local vibration of the car body. The Virtual Experiment Modal Analysis (VEMA) has the certain application prospect.