针对网架结构在动力荷载作用下失效模式的表述不明确的问题,通过分析动力失效机理,给出确定结构动力失效特征指标的原则,将特征指标归纳为塑性应变能、塑性杆件比例以及结构破坏前最大节点位移.基于模糊等价聚类的原理,应用多种相似性判定式分析特征指标之间的关系,建立模糊等价矩阵.根据最大树法和贴进度对失效模式进行分类和识别.对18个网架结构的分析结果表明,利用绝对值指数法进行模糊等价聚类,可以有效地识别网架结构动力失效模式,将其由自然语言描述转化为明确的数值表述.
The dynamic failure mechanism of grid structure was analyzed aimed at the problem that the failure mode of grid structure was hard to clearly describe when subjecting to dynamic action.The principle of choosing characteristic index needed for recognition was proposed,and dynamic failure characteristic of grid structure was summarized to plastic strain energy,ratio of plastic members and the maximum displacement before failure.Based on the theory of fuzzy equivalent clustering,quantitative relations were analyzed through four commonly used similarity measurements,and fuzzy equivalent matrixes were constructed.Then dynamic failure modes were classified and identified using maximal tree method and closeness degree respectively.The cluster results of eighteen grid structures show that the dynamic failure modes of grid structures can be effectively identified by fuzzy equivalent clustering using absolute exponent,and the vague natural-language description can be transformed to explicit quantitative-language.