混凝土模型梁模态试验方法

为有效测定混凝土模型梁的动力特性,选择一种适合于混凝土模型梁弯曲固有振动频率振型的测试方法,通过采用不同边界支承条件、激振点位置、激励大小和使用不同的激励力锤顶帽分别进行测试,发现不同边界支承条件和激励力锤顶帽对测试精度的影响很大,在不同激振点激励对频率的数值大小影响不大,但对频率的采集有影响,不同激励大小直接影响频率的采集。测试结果表明:对混凝土模型梁弯曲固有振动频率振型的测试,边界支承条件宜选择橡胶支座;激振点宜选在1/4跨点或1/6跨点处;激励力锤顶帽宜选择橡胶顶帽;激力的大小应根据不同模型梁通过试敲确定。

Modal test method for concrete beams model

In order to effectively assess the dynamic feature of the concrete beam model,an experiment testing method that is suitable for the natural frequency and mode shape of the concrete beam model was proposed.In this method,the bearing condition,the excitation position,the excitation force and the hammer cap is taken into account.The results show that the bearing condition and the hammer cap have a considerable relationship with the test,and the excitation position has a little influence on the natural frequency,but it effects the collection of frequency.The research also indicate that using rubber excitation cap can obtain good modal parameters of the concrete sited on the rubber bearings,the excitation position should be selected on the sites of 1/4 or 1/6 of the span,and the excitation force should be determined according to the different model.3 tabs,4 figs,10 refs.