基于模态应变能的损伤追踪及程度识别方法研究

Research on Tracking and Degree Identification of Damage Based on Modal Strain Energy

为降低损伤识别系统的成本,基于有限元建模及模态分析技术,提出了一种损伤追踪及其程度识别的方法。定义了一种基于模态应变能的损伤指标,追踪损伤的发生与扩展;提出了对损伤范围逐步定位的方法,通过改变传感器的数量、位置,逐步逼近损伤的扩展范围;采用基于灵敏度分析的修正方法,以试验测得低阶模态应变能为目标响应,以残余弹性模量表征各单元的局部损伤程度。使用一组带有不同裂纹的矩形板验证了该方法的有效性,试验结果表明:该方法能够有效追踪损伤的突变时间、扩展范围及局部损伤程度。

Based on the finite element modeling and modal analysis,this paper proposes a method which is used to track the damage and identify its degree,defines a damage index based on modal strain energy and traces its occurrence and expansion,then proposes the method to gradually locate the damaged position and range by changing the number and position of sensors,and then,takes the low order modal strain energy as the target response,and identifies the damaged degree of each element by the method of sensitivity-based updating.The effectiveness of this method is verified by using a set of rectangular plates with different crack sizes,and the experimental results show that this method can be used to effectively identify the occurrence,location and degree of local damages.