考虑多模态贡献的空间网格结构地震损伤评估方法

Seismic Damage Assessment Method for Spatial Grid Structures Considering Multi-modal Contribution

为避免模态跃迁现象、振型遴选方式不合理等问题对损伤评估结果精度的不利影响,提出一种考虑多模态贡献的空间网格结构地震损伤评估方法。首先,从模态推覆分析的思路出发并结合结构动力学理论推导,得到对应于单位地震力作用下考虑多阶模态贡献的等效静力位移表达式。随后,根据原结构与震损结构等效静力位移的差异构造结构地震损伤程度的表征参数,即结构整体损伤参数。最后,根据结构整体损伤参数的数值大小与变化规律,评估结构震后损伤状态与性能退化程度。单层网壳结构算例数值分析结果表明,根据本文方法计算得到的结构整体损伤参数在考虑多阶模态贡献的基础上,可较为准确地评估空间网格结构地震损伤状态,所得结果与结构特征响应对比具有较好的一致性,同时在严重损伤情况下也可保证评估结果的准确性。

In order to avoid the adverse effects of modal transition and unreasonable mode selection on the accuracy of damage assessment results,a seismic damage assessment method for spatial grid structures considering the contribution of multiple modes was proposed.Firstly,based on the idea of modal pushover analysis and the structural dynamic theory,the equivalent static displacement expression corresponding to the multi-modal contribution under unit seismic force was obtained.Then,according to the difference between the equivalent static displacement of ori-ginal structure and damaged structure,the structural characterization parameter of the earthquake damage degree,namely,the overall damage parameter,was generated.Finally,the state of structural damage and performance degradation was assessed based on the magnitude and change of the overall damage parameters of the structure.The numerical analysis results of single-layer reticulated shell model show that the overall damage parameter of the structure calculated according to the method in this paper can more accurately assess the seismic damage degree of the space grid structure based on considering the multi-mode modal contributions.The obtained results are in good agreement with the comparison of structural characteristic response.In addition,the accuracy of the assessment results can be guaranteed in the case of severe damages.