传统的构件重要性分类方法通常仅针对线弹性结构，不适用于非线性效应较强的网壳结构，同时其分类依据存在一定局限性。为解决上述问题，文中针对网壳结构提出了一种基于应变能的构件重要性分类方法。基于应变能理论，引入了临界点总应变能的概念; 以临界点总应变能为评价指标分析局部构件损伤对结构整体承载性能的影响，由此确定构件的重要程度。将结构临界点总应变能折减系数作为构件重要性系数，参照现行规范的构件重要性划分原则，根据 K-medoids 分类方法提出了一种变界限的网壳结构构件重要性分类方法。对凯威特型球面网壳算例的分析结果表明，构件重要性分类界限不宜采用单一的固定值; 不同损伤状况下，重要构件的数量及分布位置不同，应根据实际情况计算确定; 文中方法相较于构件设计应力比方法能够提供更多信息，便于准确识别结构系统中的重要构件; 基于拆除构件法的构件重要性判定方法不适用于常规的结构检测鉴定。

The traditional classification methods of member importance are often exclusively applied to linear-elas-tic structures，and they are not suitable for latticed structure with strong nonlinear effect． Meanwhile，these classi-fication methods also have limitations． To solve this problem，a classification method of member importance based on strain energy was proposed for latticed structure． Based on strain energy theory，the concept of total strain ener-gy at critical point was introduced． Taking total strain energy at critical point as the evaluation index，the influence of local member's break down on the load-carrying capability of whole structure was analyzed． Thus each member's importance was figured out． Ｒeduction coefficients of total strain energy at critical point were considered as indexes of member importance． According to present principles of member importance classification，and based on K-me-doids classification method，a classification method of member importance with non-fixed boundary was proposed．The analysis results of Kiewitt lattice shells show that the classification boundary of member importance should not be fixed to a certain value． The number and location of important members vary in different failure cases，so they should be determined based on actual information． Method proposed in the paper can provide more information
than the design stress ratio method in detecting important members in structure． Classification method of member importance based on alternative path method should not be used for the normal inspection and appraisal of struc-tures．