针对工程上含有复杂链接机构的结构在有限元建模时边界约束无法准确确定问题,发展了一种基于试验模态参数的结构边界条件优化设计方法,将模态试验和计算模态分析相结合,通过基于遗传算法的多目标优化方法,以试验模态的频率和振型参数为优化目标,通过调整边界约束得到准确的有限元模型,获取准确的质量信息。通过一个有试验数据的三维空气舵算例,验证了该方法的可行性并达到了修正试验质量参数的效果。
Accurate finite element is the premise for modal analysis of structure. For the Structure containing com-plex connecting mechanism, highly accurate natural frequencies and mode shapes can usually be obtained by ground modal test, but the error of modal mass is relatively large. The finite element model can accurately describe the geometry of the structural and material information, but it is difficult to give accurate boundary constraints. The combination of modal testing and finite element modeling is used in this paper. The paper develop an optimization method for uncertain boundary constraint of structure dynamical model based on test modeling; the method uses multi-objective genetic algorithm ( GA) , the initial finite element model is optimized by replacing structural elastic boundary constraint with the norm of natural frequencies and mode shapes. The boundary constraint optimization of a peer-section beam is used to verify the feasibility of the proposed method. And then a control surface model with modal test data is used to verify the applicability of the presented method. The results indicate preliminarily that the natural frequencies and mode shapes obtained with the optimization method agreed respectively with those obtained with modal test very well. In addition, accurate modal mass obtained with optimization can correctly revise the mo-dal mass obtained with modal test.