基于模态分析的某振动试验方法改进

Improvement of Vibration Testing Method Based on Modal Analyzing

目的对该试验夹具进行改进设计,使试验夹具首阶模态频率大于60 Hz。方法基于模态分析方法,分别采取改进夹具结构形式和改变夹具边界条件两种改进方式进行优化设计。结果根据模态分析结果发现,夹具结构形式改进对模态频率提高的效果不明显,改变边界条件能够显著提高夹具频率。改进后试验夹具首阶模态频率为69.5 Hz,大于试验输入载荷频率范围。结论试验夹具的固有频率应避开振动试验输入载荷频率范围,避免对试验结果造成影响。

The paper aims to improve the design of test fixture and make the first order modal frequency of the test fixture be larger than 60 Hz. Two methods, namely improving the structure and changing boundary conditions, were adopted for optimization design based on modal analyzing. From the results of modal analysis, improving boundary condition was valid to improve the modal frequency;while changing the boundary condition can significantly improve the fixture frequency. The first order modal frequency of the improved fixture was 69.5 Hz, which was greater than the input load frequency range. The nature frequency of test fixture should avoid the input load frequency range of vibration testing, to avoid influences to the test result.