基于模态应变能变化率的L形管道损伤识别

为识别L形管道的局部损伤，根据局部结构的振型、刚度矩阵和固有频率，得到管道局部的模态应变能变化率指标，并利用有限元软件ABAQUS模拟不同参数模型，得到低阶模态数据以及管道各单元的模态应变能变化率。模拟结果表明：采用该损伤指标，能够较好地确定L形管道的损伤位置，并且直管单元比弯曲单元对该指标更敏感；对同一单元不同损伤程度的对比，可以反映其损伤程度的大小；对L形管道不同弯曲角度进行模拟，该指标对不同弯曲角度L形管道的损伤识别具有普遍性；对L形管道不同缺陷长度进行模拟，模态应变能变化率指标在缺陷取周向长度的1/32时达到极限。

Damage identification of L-shaped pipeline based on#br# modal strain energy change rate

In order to identify the local damage of L-shaped pipeline, the local modal strain energy change rate index of the pipeline is obtained according to the vibration mode, stiffness matrix and natural frequency of the local structure, and the finite element software ABAQUS is used to simulate different parameter models, and the low-order modal data and the modal strain energy change rate of each element of the pipeline are obtained. The simulation results show that the damage location of L-shaped pipeline can be well determined by using this damage index, and the straight pipe element is more sensitive to this index than the bending element, and the comparison of different damage degrees of the same element can reflect the degree of damage. For different bending angles of L-shaped pipes, this index is universal for damage identification of L-shaped pipes with different bending angles. The different defect lengths of L-shaped pipes are simulated, and the modal strain energy change rate index reaches the limit when the defect circumferential length is 1/32.