阶梯悬臂梁的双裂纹参数两步识别法  

CRACKS IDENTIFICATION OF TWO-STEP IN A STEPPED CANTILEVER BEAM

作　　者：张伟伟[1] 程良彦[1] 王志华[2] 马宏伟[1] 

机构地区：[1]暨南大学理工学院,广州510632 [2]太原理工大学应用力学研究所,太原030024

出　　处：《机械强度》2008年第4期534-538,共5页Journal of Mechanical Strength

基　　金：国家自然科学基金(10672067);广东省高校自然科学重点研究项目(05Z003);广东省科技攻关计划研究项目(2006B12401008);山西省自然科学基金(20041003)资助~~

摘　　要：以等效弹簧模拟裂纹引起的局部软化效应,应用Bernoulli-Euler梁理论建立双裂纹阶梯悬臂梁的振动特征方程。鉴于方程含有较多的未知量,提出联合小波变换和结构测量频率的裂纹参数识别两步法。首先,含裂纹悬臂梁的一阶模态作为信号用于连续小波变换,通过小波系数的局部极值可以清楚地确定结构的裂纹位置。其次,将识别得到的裂纹位置代入双裂纹阶梯悬臂梁的特征方程,最后通过绘制两个裂纹的等效柔度的等值线图,通过交点确定满足特征方程的两个裂纹的等效柔度,并进一步确定裂纹深度。最后利用数值算例验证该方法的有效性。A two-step method is suggested to identify separately the location and the depth of cracks in a stepped cantilever beam, which incorporates the merit of wavelet transform with the merit of natural frequency measurement. Firstly, the wavelet analysis is apphed to the fundamental vibration mode of the stepped beam, The crack location is found by the peak value of the wavelet coefficients. Secondly, based on the identified crack locations, a frequency-based method requiring the first two tested natural frequencies only is used to further identify the crack depths. Numerical results of crack identification of a stepped cantilever beam show that the suggested method is feasible.

关 键 词：悬臂梁 频率 小波变换 裂纹 

分 类 号：O235[理学—运筹学与控制论] TP277[理学—数学]