利用应变模态差识别弯管内部损伤

Internal Damage Identification of Elbow Pipe by Strain Modal Difference

为研究利用应变模态差识别弯管内部损伤的方法,以损伤前、后的应变模态差作为弯管损伤识别的损伤指标对其展开研究。首先,基于位移模态和应变模态的模态叠加特性和正交性推导了应变模态差公式;其次,利用有限元软件ABAQUS建立不同工况的弯管简化模型进行数值模拟。处理分析得到应变模态差曲线,以此判断损伤的存在和位置以及损伤程度。结果表明,通过该损伤指标能很好识别弯管损伤的存在和位置,并能有效地反映其损伤的程度;改变弯管的径厚比和弯曲形式,该指标对弯管损伤识别仍然适用。证明了基于应变模态差的弯管内部损伤识别的可行性。

In order to study the method of identifying internal damage of elbow pipe by strain modal difference,the strain modal difference before and after damage was taken as the damage index of the damage identification of elbow pipe.Firstly,based on the superposition and orthogonality of displacement modal and strain modal,the formula of strain mode difference was derived.Secondly,the finite element software ABAQUS was used to establish the simplified elbow pipe model under different working conditions for numerical simulation.Finally,the strain modal difference curve was obtained by processing and analyzing,so as to judge the existence,location and severity of the damage.The results show that the damage index can identify the existence and location of the damage,and effectively reflect the severity of damage.By changing the diameter-thickness ratio and bending form of the elbow pipe,the damage index is still applicable to the damage identification of elbow pipe.The feasibility of damage identification based on strain modal difference is proved.