空间结构静力稳定分析与评定的特征刚度法

Characteristic stiffness method for static stability analysis and assessment of spatial structure

为了直观反映稳定分析中结构整体性态的变化,解决荷载-位移曲线特征点的选取问题,提出特征刚度概念并导出计算公式,证明了特征刚度为零可以作为极值型屈曲结构稳定性临界状态的判定依据;结合增量累积的荷载功和结构特征位移,提出结构静力分析的全过程特征曲线,采用该曲线分析结构受载全过程中整体刚度的变化.选取一个K6型网壳和一个会议中心屋盖网壳,采用特征刚度法进行静力稳定分析,分析结果表明:计算得到的结构失稳临界荷载与基于单点荷载-位移曲线所得结果相同;相对于传统的单点荷载-位移曲线,特征曲线不依赖于结构特征点的选取,且形态稳定,可以直观反映结构整体刚度的特征.

A scalar quantity denoted characteristic stiffness was suggested and its calculation formula was derived in order to directly reflect the evolution of overall structural behavior in static stability analysis and solve the problem of how to properly select these representative node.The state of structure can be defined as unstable when the value of structural characteristic stiffness is equal to zero in stability analysis.The characteristic curve was proposed to describe the overall mechanical behavior of the structure among the stability analysis combined with the accumulated work increment and the characteristic displacement.The static non-linear analysis was conducted on a K6 single-layer reticulated shell and a conference center roof shell.The critical loads obtained from the characteristic curves are equal to those from single nodal loaddisplacement curves.The characteristic curves are more stable and easier for understanding compared with the single nodal load-displacement curves.because the characteristic curves do not rely on representative node selection and can reflect the overall structural stiffness.