考虑模糊失效准则的单层球面网壳结构多维联合地震易损性分析

MULTI-DIMENSIONAL JOINT SEISMIC FRAGILITY ANALYSIS OF SINGLE-LAYER RETICULATED SPHERICAL SHELL STRUCTURE CONSIDERING FUZZY FAILURE CRITERIA

  • 摘要: 为在网壳结构的地震易损性分析中考虑多维地震需求间的相关性影响,引入Copula函数建立结构多维地震需求的联合分布函数,同时为考虑结构性能极限状态的模糊不确定性,基于模糊失效准则构建结构多维联合地震易损性分析方法。从位移和能量角度建立不同性能指标下的结构概率地震需求模型,并采用隶属函数描述极限状态的模糊性,基于模糊-概率积分理论给出考虑失效准则模糊性的结构地震易损性函数。选择最优Copula函数并结合单项性能指标的失效概率,获得考虑多维地震需求相关性的联合概率地震易损性曲线。结果表明:与采用单参数性能指标的地震易损性相比,考虑模糊失效准则的多维联合地震易损性分析可以更加准确地预测结构在不同破坏等级下的失效概率,一定程度上提高了结构的地震风险值,有利于提升结构的安全性。

     

    Abstract: In order to consider the influence of the correlation between multi-dimensional seismic demands in the seismic fragility analysis of reticulated shell structures, the Copula function is introduced to establish the joint distribution function of the structural multi-dimensional seismic demand. At the same time, in order to consider the fuzzy uncertainty of the limit state of the structural performance, a seismic fragility analysis method for multi-dimensional joints of the structure is constructed upon the fuzzy failure criterion. The structural probabilistic seismic demand models with different performance indexes are established from the perspective of displacement and energy, and the membership function is used to describe the fuzziness of the limit state. Furthermore, the structural seismic fragility function considering the fuzziness of failure criteria is presented, based on the fuzzy probability integral theory. Then the joint probabilistic seismic fragility curve considering the correlation of multi-dimensional seismic demand is obtained by selecting the optimal Copula function and combining the failure probability of single performance index. The analysis results show that: compared with the seismic fragility using single-parameter performance index, the multi-dimensional joint seismic fragility considering the fuzzy failure criterion can predict the failure probability of the structure under different damage levels more accurately. To a certain extent, the seismic risk value of the structure is improved and it is beneficial to improve the safety of the structure.

     

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