含裂纹梁参数的谐响应识别

发布时间：2018-09-05 06:24

【摘要】：主要研究含裂纹梁在简谐激励作用下的动力特性,提出一种依据幅值变化对裂纹参数进行识别的新方法。首先,在振动过程中考虑裂纹的呼吸特性,以悬臂梁为例建立含裂纹梁的二维有限元模型,指出在一般激励频率下,其对应的幅值均是明显信号,可用来描述裂纹梁的动力特性。其次,当激励频率分别取无裂纹梁一阶频率的1/4和二阶频率的1/4时,幅值随裂纹参数的变化明显不同,可依据响应幅值的变化对裂纹参数进行识别。然后,利用曲面拟合技术绘出幅值变化曲面,对未知参数的裂纹进行识别,验证了该方法的有效性,并归纳出利用幅值变化对任意裂纹参数进行识别的基本步骤。最后,针对无裂纹梁频率计算可能存在误差的情况,分析识别方法的鲁棒性,结果显示即使最大误差为10%,该方法也能对裂纹参数进行准确识别。
[Abstract]:The dynamic characteristics of cracked beams under harmonic excitation are studied and a new method for identifying crack parameters is proposed. First of all, considering the respiratory characteristics of cracks during vibration, a two-dimensional finite element model for cantilever beams with cracks is established. It is pointed out that the corresponding amplitudes are obvious signals at general excitation frequencies. It can be used to describe the dynamic characteristics of cracked beams. Secondly, when the excitation frequency is 1 / 4 of the first order frequency of the cracked beam and the 1 / 4 of the second order frequency, the amplitude varies obviously with the crack parameter, and the crack parameter can be identified according to the change of the response amplitude. Then, the amplitude varying surface is drawn by the surface fitting technique, and the cracks with unknown parameters are identified. The validity of the method is verified, and the basic steps of identifying arbitrary crack parameters by using amplitude variation are summarized. Finally, the robustness of the identification method is analyzed in view of the possible errors in the frequency calculation of the cracked beam. The results show that the method can accurately identify the crack parameters even if the maximum error is 10.
【作者单位】：大连理工大学工程力学系工业装备结构分析国家重点实验室;
【基金】：国家自然科学基金(11272074) 国家科技重大专项(2011ZX02403)资助项目
【分类号】：O346.1

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