振动试验中非一致基础激励行为的表征与量化

Characterization and Quantization Research of Non-uniform Base Excitation in Vibration Test

针对振动试验中振动台台面输出并非完全理想的一致基础激励,从而可能导致试验中出现非预期响应行为的问题,通过理论分析、数值模拟和试验验证,采用模态叠加理论,将振动台台面响应分解到模态空间,开展了台面非一致基础激励的表征与量化研究,并结合某典型结构的空台面、轴向及横向随机振动试验数据,从响应功率谱密度曲线和均方根值2个方面进行了台面非一致基础激励的量化。研究结果表明,振动台台面输出的非一致性是不同程度存在的,台面的弹性支撑以及试验结构的对称性等对台面输出的一致性影响较大。

Considering the output of shaking table is not a kind of absolutely uniform base excitation in vibration test,some unexpected response behavior could be occurred. With the research of theoretical analysis,numerical simulation and experiment confirmation based on mode superposition theory,the output response of shaking table is decomposed in mode space,then the non-uniform base excitation is characterized and quantified. Furthermore,with the experiment data analysis of empty mesa,axis vibration and transverse vibration test of typical structure,the non-uniform base excitation is quantified from two aspects of response power spectrum and root mean sqaure. Theoretical and experimental results indicated that the existed non-uniform base excitation can be caused by two important factors including the elastic support between armature and table top,and the symmetry of test structure are two important factors that could cause the non-uniform output of shaking table.