Abstract:

Based on the problems of vibration fatigue damage in an elastic beam which was widely used in aircrafts, a novel method was proposed for structural damage detection via change of the unit modal strain energy. A principle was employed that the modal properties will be changing as the structure was damaged. An indicator was built through comparing the modal strain energy before and after an elastic beam was injured. Firstly, an elastic beam's stiffness was regarded that it was built by unit stiffness, and a formula was defined for unit stiffness sensitivity. Thereafter, the contact between elastic beams before and after damaged was built by modal strain energy. Results are given after simulation and experiments, the accuracy and efficiency of this method were verified.

Key words: damage detection, modal strain energy, elastic beam, vibration fatigue

摘要：

针对飞行器弹性梁结构的振动疲劳损伤问题，基于单元模态应变能的变化提出了一种新的结构损伤识别方法。该方法以结构损伤会导致其模态性能变化为原则，通过对比结构单元损伤前后模态应变能的变化率来构建损伤指标。在构建损伤指标之前，假定弹性梁的刚度是由单元刚度组成的，在定义单元刚度灵敏度公式的基础上，建立了弹性梁损伤前后模态应变能变化的联系。最后采用数值计算和实验测试方法，得到了弹性梁损伤状态的识别结果，验证了该方法对损伤识别的正确性和有效性。

关键词: 损伤识别, 模态应变能, 弹性梁, 振动疲劳