Research And Application On Structural Vibration Modal Test Optimization Technique

It had been all rely on the experience and trials of the technician to make a reliable, effective and reasonable structure vibration modal test since long term ago. The reliability and effectiveness was bad, the test period was long and the cost was high of the modal test, which without theories and techniques guiding. Therefore, it was great meaning to build the structure vibration modal test optimization technique which could guide and optimize the structure vibration modal test.This paper start with the purpose and requirements of the suspension, driving and measurement positions of the modal test. Based on the structure finite element modal parameter to study the structure vibration modal test optimization technique. The content included the following aspects.(1) First of all, studied a method to extract the surface node modal parameters of the structure finite element model from the finite element software. Secondly, presented the optimum displacement response method on the basis of the original suspension optimization method. The new method made use of the modal parameters of the structure finite element and made up for the insufficient of the original method. Then presented mode shape weighted effective independent method on the basis of effective independent method in optimizing the measurement positions. The new method could fulfill more modal test requirements. Studied the method to get rid of the worst driving positions from the optimum positions so as to get the most suitable driving positions.(2) Through a component example to tell the way to get the surface node modal parameters of the finite element model and the effects the method had achieved. Then analyzed the different results of all optimum methods in optimizing the suspension, driving and measurement positions. The results verified the new methods can achieve better optimization effects and fulfill more modal test requirements.(3) Using modal test optimization techniques to guide and optimize the compressor wheel modal test. Through analyzed the correlation of the compressor wheel modal test results, we found the compressor wheel modal test which had been optimized by the modal test optimization technique could completely and accurately test all concerned modal parameters. The result verified the effectiveness and the reliability of the modal test optimization technique.