基于应变模态的波纹板损伤诊断及疲劳寿命预测

Damage Diagnosis and Fatigue Life Prediction of Corrugated Plate Based on Strain Mode

为确定波纹板的疲劳损伤位置及损伤程度,利用模态理论分析波纹板的位移和应变模态振型,结果表明,波纹板损伤前后的频率、位移振型相对变化率很小且无突变,而应变模态振型在损伤位置产生了尖峰突变,且突变值随着损伤程度的增加而增大,最终确定选取应变模态振型作为判断波纹板损伤位置和大小的指标;利用MATLAB软件拟合得到损伤程度和应变模态变化率之间的关系。由波纹板的损伤程度确定波纹板的初始裂纹尺寸,再根据Paris公式即可得到波纹板的疲劳裂纹扩展剩余寿命。

To determine fatigue damage location and damage degree of corrugated plate,using the theory of modal analysis of the displacement and strain modal vibration mode of the corrugated plate,the results show that corrugated plate before and after the damage of the relative change rate of frequency,displacement modes is small and no mutation,and the strain modal vibration mode produced spike mutation,the damage position and mutation value increases with the increase of damage degree,ultimately determine the strain modal vibration mode is selected as the parameters of the corrugated plate damage location and size.The relationship between damage degree and strain mode change rate is obtained by MATLAB software fitting.The initial crack size of the corrugated plate is determined by the damage degree of the corrugated plate,and then the residual life of fatigue crack propagation of the corrugated plate can be obtained according to the Paris formula.