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在动力荷载作用下单层网壳结构杆件受力和结构承载力处于动态变化中,因此要得到准确的结构实时动力响应,必须建立能够模拟杆件实时受力性能的杆件计算模型。根据单层网壳结构杆件的受力特点,总结出受压杆件的两种失稳类型。引入国际标准化组织推荐的空间受力圆钢管失稳判别准则,采用3节点塑性铰单元和Marshall模型分别模拟受压杆件失稳前后的受力性能,建立了杆件计算模型,该计算模型能够模拟杆件在动力荷载作用下经历失稳、拉直与塑性铰形成直至消失的过程。计算结果表明:采用有限元软件通用梁单元模拟单层网壳结构杆件将高估结构在地震作用下的承载力;应用本文的杆件计算模型,可以准确得到单层网壳结构在地震作用下的杆件受力变化过程及由此造成的结构承载力的动态变化过程,实现了对单层网壳结构动力响应全过程的精细化模拟。
Under the action of dynamic load, the stress and the bearing capacity of the single-layer reticulated shell structure are in dynamic changes. Therefore, in order to obtain the accurate real-time dynamic response of the structure, it is necessary to establish the model of the bar that can simulate the real-time force performance of the bar. According to the force characteristics of the single-layer reticulated shell structure, two types of buckling of the bar under compression are summarized. The criterion of dislocation stability of circular steel tube under space force recommended by International Organization for Standardization (ISO) was introduced. The mechanical behavior before and after the failure of the pressed rod was simulated by the 3-node plastic hinge unit and the Marshall model. The calculation model of the rod was established. Under the action of dynamic load, the simulation rod experiences instability, straightening and plastic hinge formation until it disappears. The calculation results show that using the universal beam element of finite element software to simulate the single-layer reticulated shell member will overestimate the bearing capacity of the structure under the action of earthquake. By using the calculation model of the member in this paper, the effect of the single-layer reticulated shell structure on the earthquake action Under the force change process of the bar and the dynamic change of the bearing capacity of the structure, the detailed simulation of the whole process of the dynamic response of the single-layer reticulated shell structure is realized.