基于第一阶模态轴向位移差变化率的轧辊裂纹判断方法研究

Study on the Method to Judge Crack of Roller Based on the Change Rate of the Axial Displacement Difference in the First Mode

基于空间振动模态的特点,提出了模态轴向位移差变化率参数,用于轧辊的裂纹识别。通过建立无裂纹、含表面裂纹和含内部裂纹轧辊的三维有限元模型,计算轧辊的位移模态。通过提取轧辊表面一条母线上的第一阶模态的轴向位移分量,分析了含表面裂纹和内部裂纹的轧辊的第一阶模态轴向位移差变化率随裂纹位置和深度的变化规律。结果表明:在裂纹位置第一阶模态轴向位移差变化率会出现突变尖峰,且随着裂纹深度的增大,突变值也增大。因此,用第一阶模态轴向位移差变化率识别轧辊的裂纹损伤是可行的。

A parameter called the change rate of the mode axial displacement difference is proposed based on the feature of vibration mode, and is used to judg crack of roller. Displacement mode of roller is calculated by establishing the three-dimensional finite element models of roller with no crack, external crack and inner crack, respectively. The influence of the position and depth of crack on the change rate of the axial displacement difference in the first mode of roller with external and inner crack is also analyzed by extracting the axial displacement in the first mode of a generatrix on the surface of the roller. The results demonstrate that the change rate of the axial displacement difference in the first mode exist a peak at the crack position. And the peak goes higher when the crack is deeper. Therefore, it is feasible to identify the roller＇s crack damage by the change rate of the axial displacement difference in the first mode.