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针对飞艇骨架结构中损伤引起的模态跃迁现象导致无法通过匹配损伤前后动态特性参数变化来识别损伤的难题,给出3种只基于损伤后振动响应信息进行损伤识别的动态方法。通过模态分析方法获得结构的模态参数,分别推导模态振型曲率法、均布载荷面曲率法和虚拟轴向应变法等3种损伤识别算法。定义损伤指标,并根据损伤指标局部峰值来识别和定位损伤杆件。以半硬式飞艇常见狭长构型三角截面碳纤维复合材料桁架为例,结合有限元法和自编MATLAB程序进行损伤识别仿真研究,影响参数包括损伤类型、损伤位置、损伤程度和噪声量级等,最后对损伤识别算法的有效性进行试验验证。结果表明新损伤识别方法对损伤敏感,在环境噪声工况下能准确识别和定位单个和多个损伤杆件。文中方法均基于结构整体振动信息进行损伤杆件识别,将来可用于构造飞艇骨架实时结构健康监测系统。
Aiming at the problem that the modal transition caused by the damage in the airship skeleton structure can not identify the damage by matching the dynamic characteristic parameters before and after the damage, three dynamic methods for damage identification based on the post-damage vibration response information are given. The modal parameters of the structure were obtained by modal analysis, and three kinds of damage identification algorithms such as modal curvature method, uniform load surface curvature method and virtual axial strain method were deduced respectively. The damage index is defined, and the damage rod is identified and located according to the local peak value of the damage index. Taking the narrow-profile triangular cross-section carbon fiber composite truss of semi-rigid airship as an example, the finite element method and self-compiled MATLAB program are used to study the damage identification simulation. The influence parameters include damage type, damage location, damage degree and noise level, and finally The effectiveness of damage detection algorithm is validated by experiments. The results show that the new damage detection method is sensitive to damage and can accurately identify and locate single and multiple damaged rods under environmental noise conditions. The methods in this paper are based on the vibration information of the whole structure of the damaged rod identification, the future can be used to construct airship skeleton real-time structural health monitoring system.