基于能量有限元法的损伤板结构振动分析

摘要

工程结构在服役期间会出现各种形式的损伤,其结构动力学参数和能量传播形式也会随之产生变化,因此基于振动的结构损伤识别得到了广泛的研究并在工程运用中具有重要的意义.采用能量有限元法对含有损伤的平板和耦合板结构的振动特性进行分析,算例分析中分别采用能量有限元法和有限元法对平板的能量密度进行了计算和对比,验证了能量有限元法的准确性.在此基础上提出了基于能量密度变化和结构声强变化的两个损伤指标,并对损伤识别指标进行了可视化分析,随后通过算例对比进一步确定基于能量有限元得到的结构声强变化能够有效地识别板结构的损伤部位,并对含有损伤的耦合板的结构声强进行了研究,为今后将能量有限元法进一步应用到结构损伤识别中提供了基础.%Cracks and other forms of damage may appear during engineering structures' service.Their structural dynamic parameters and energy transmission form also change subsequently,so the identification of structural damages based on vibration is studied extensively and has very important significance in engineering application.Here,the energy finite element method was adopted to analyze vibration characteristics of both planar plates and coupled plates with damages.In example analyses,the energy finite element method and the finite element one were used,respectively to compute and compare a planar plate's energy density.The correctness of the energy finite element method was verified.Furthermore,the two damage identification indexes based on the energy density variation and the structural acoustic intensity one,respectively were proposed.Their visualized analyses were conducted.Through examples comparative study,it was determined that the structural acoustic intensity changes obtained with the energy finite element method can effectively identify the damage position of plate structures.The structural acoustic intensity changes of coupled plates were studied with the same method.The results provided a foundation for further application of the energy finite element method in structural damage identification.