移动载荷作用下起重机主梁损伤识别  

Damage Identification of Crane Girder under Moving Load

作　　者：房连栋 朱松青[1] 杨会超 FANG Liandong;ZHUSongqing;YANG Huichao(School of Mechanical Engineering,Nanjing Institute of Technology,Nanjing 211167,China)

机构地区：[1]南京工程学院机械工程学院,江苏南京211167

出　　处：《南京工程学院学报（自然科学版）》2023年第4期78-84,共7页Journal of Nanjing Institute of Technology(Natural Science Edition)

摘　　要：作为桥式起重机上关键部件,主梁的安全性受到极大关注.以桥式起重机主梁为研究对象,对移动载荷作用下主梁裂纹损伤进行识别研究.首先建立主梁有限元模型,通过生死单元法杀死损伤单元模拟裂纹损伤,利用ANSYS瞬态动力分析法实现移动载荷加载,并将获得的主梁位移信号与解析解进行对比;然后对位移信号差分获取加速度信号,应用小波变换对主梁1/4、1/2、3/4位置的加速度信号进行分解,分析后选择包含损伤信息的高频部分小波系数构建损伤定位系数来实现损伤定位;最后利用损伤定位系数能量的对数构建损伤程度系数,结合模型匹配法,利用三次样条拟合建立损伤程度方程,识别损伤程度.该研究为起重机主梁移动载荷下的损伤识别提供重要理论参考.As a key part of bridge crane,the safety of the main beam has been paid great attention.This paper focuses on the crack damage identification of the main beam under the action of moving load.Firstly,the finite element model of the main beam was established,incorporating the life-or-death element method to simulate crack damage.The transient dynamic analysis method of ANSYS was used to simulate the effects of moving loads,and the displacement signal of the main beam was compared with the analytical solution.Then,the acceleration signals were obtained by differential displacement signals,and the acceleration signals at the quarter,mid-span and three-quarters positions of the main beam were decomposed by wavelet transform.After analysis,the high-frequency wavelet coefficients containing damage information were selected to construct the damage location coefficient mwd to realize the damage location.Finally,the damage degree coefficient emwd was constructed by using the logarithm of mwd energy.Combined with the model matching method,the damage degree equation was established by using cubic spline fitting to identify the damage degree.This study provides an important theoretical basis for damage identification of crane girder under moving load.

关 键 词：起重机主梁 移动载荷 损伤识别 小波分析 

分 类 号：TH215[机械工程—机械制造及自动化]