温度荷载作用下钢桁架的弹塑性后屈曲反应分析

Inelastic Postbuckling Response of Steel Trusses Under Thermal Loadings

针对温度荷载作用下钢桁架的弹塑性后屈曲分析提出一个有限元计算方法。首先,推导出整体的力-位移关系。然后构建一个有限元模型,用于模拟温度荷载作用下桁架构件的弹塑性非线性性能。由于抵抗伸长和材料软化而产生的作用力,分别作为温度荷载和渐减的结构荷载考虑。为考虑到温度升高时材料的软化性能,采用了EC3中提议的折减系数。桁架假定状态为经受温度恒定下荷载逐渐加大,或者是恒定荷载下温度逐渐升高。将修正后的广义位移控制法用于解决桁架的后屈曲反应。结果显示:桁架的临界荷载(或温度)会随着预加热(或预加载)的增加而明显降低,而且如果考虑到屈服的影响,桁架的断裂强度会比弹性临界荷载小很多。从设计观点来看,临界荷载-温度曲线可以很好地表现弹性桁架的整体性能。

The paper presents a finite element procedure for the inelastic postbuckling analysis of steel trusses under thermal loadings. First, the force-displacement relation in total form is derived. Then an element is formulated to simulate the inelastic nonlinear behavior of truss members under thermal loadings. The actions due to restraint against elongation and material softening are referred to as thermal loads and reduced member loads, respectively. To account for the material softening at elevated temperatur...