基于应变模态的振动筛上横梁疲劳损伤分析  

FATIGUE DAMAGE ANALYSIS OF VIBRATING SCREEN UPPER BEAM BASED ON STRAIN MODAL ANALYSIS

作　　者：张则荣[1] 樊智敏[1] 王永岩[1] 杨福芹[1] 徐俊[1] 

机构地区：[1]青岛科技大学机电工程学院,青岛266061

出　　处：《机械强度》2017年第5期1187-1192,共6页Journal of Mechanical Strength

基　　金：国家自然科学基金(51674149);山东省自然科学基金(ZR2015EM035)资助~~

摘　　要：基于模态理论建立了振动筛位移和应变模态参数识别模型,仿真分析了振动筛上横梁产生疲劳损伤裂纹时位移和应变模态参数的变化。分析结果表明上横梁产生疲劳裂纹后的模态频率和位移振型较疲劳损伤前均无显著变化,而应变模态振型在疲劳裂纹处发生了显著的突变,其中弯曲应变模态较扭转应变模态对疲劳损伤裂纹更敏感。以振动筛上横梁产生疲劳损伤裂纹前、后的应变模态变化率为指标判定疲劳损伤程度,由损伤程度即可确定上横梁疲劳裂纹尺寸,进而可由Paris公式的积分形式计算振动筛上横梁的疲劳剩余寿命。基于应变模态变化预测振动筛上横梁的疲劳损伤程度和疲劳剩余寿命,将有助于对其进行动态优化设计,从而提高振动筛的使用寿命。The displacement and strain modal parameters identification models of the vibrating screen were built based on modal theory,the variations of the displacement and strain modal parameters were analyzed for the vibrating screen upper beam with fatigue damage crack. The results show that the modal frequencies and the displacement mode shapes have no obvious mutation between intact and damaged upper beam,but the strain mode shapes have mutation peaks at the location of the fatigue damage crack,furthermore,the bending strain mode is more sensitive to fatigue damage crack than the twisting strain mode.Thus a fatigue damage indicator is defined by using the strain modal variable ratio between the intact and damaged upper beam,the fatigue crack size is determined by damaged degree of the upper beam,then the residual life of fatigue crack propagation of the upper beam is calculated by the Paris formula of integral form. The predictions of the damaged degree and the fatigue residual life of the vibrating screen upper beam are beneficial to dynamic optimization design,which can improve the service life of the vibrating screen.

关 键 词：振动筛 上横梁 应变模态分析 疲劳损伤 剩余寿命 

分 类 号：TD452[矿业工程—矿山机电]