基于应变模态测试的复合材料梁的刚度识别

Stiffness Identification of Composite Beam Based on Tested Strain Mode

采用锤击法对玻璃纤维增强塑料梁在局部附加质量块前后进行模态测试,结果表明,附加质量后,结构固有频率下降,同时,在附加质量所在的节点位置,应变模态有突变产生。文中基于应变模态测试结果对梁的刚度进行识别。以识别结果为已知量,用数值模拟实验的方法进行检验。检验得出识别结果和模拟实验相吻合,从而验证识别方法的可信性。此识别方法不需已知梁未损伤前的物性参数,只需知某部分的刚度,即可识别出所有单元的刚度。

The strain model tests on a glass fiber reinforced plastic beam by impact method were completed by two sit-uations,whether an iron block attached on part of the beam or not. The test results show that the natural frequencies of the structure decrease when an iron block attaches on the beam. Meanwhile, nearby the position on which the iron block is attached, the strain mode mutates. Stiffness identification of the beam was based on the results of strain mode test in this article. The identification results were verified by numerical simulations. What is more, this identification method does not need the physical parameters of the beam before it is damaged. If only the stiffness of a part is known, the stiffness of ev- ery part of the structure can be identified.