摘要
从线弹性断裂力学的角度考虑裂纹引起的局部附加柔度,进而构造了小波有限元裂纹刚度矩阵,提出了基于小波有限元的裂纹故障诊断算法,克服了裂纹奇异性给传统有限元算法造成的困难.将系统前3阶的固有频率作为输入,绘制裂纹等效刚度与裂纹位置的3条曲线,根据曲线的交点可以预测出裂纹的位置与尺寸.用于研究该算法精度的裂纹轴数值算例表明:裂纹位置与尺寸的辨识误差均不超过2%,这为工程实践中早期微弱裂纹的故障预示与诊断提供了新的方法.
The additional flexibility near the crack vicinity is evaluated according to linear and elastic fracture mechanics theory. The wavelet finite element stiffness matrix of crack is constructed and the algorithm for crack fault diagnosis based on wavelet finite elements is proposed, which overcomes the deterioration in the performance of classical finite element method caused by the crack top singularity. Graphs of crack equivalent stiffness versus crack location are plotted by providing the first three natural frequencies as an input. The intersection of the three curves predicts the crack location and size. The numerical examples of cracked shafts are presented to verify the accuracy of the method. It is observed that the identification error of crack location and size are both less than 2%. The new method for prognosis and diagnosis of incipient small crack can be applied to engineering practice effectively.
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2004年第3期295-298,共4页
Journal of Xi'an Jiaotong University
基金
国家自然科学基金资助重点项目(50335030
50305012)
西安交通大学自然科学基金资助项目.
关键词
小波有限元
裂纹
故障预示
故障诊断
Finite element method
Natural frequencies
Stiffness matrix
Wavelet transforms