具有初始位移压杆在均布荷载作用下的承载力

格构式拼组结构一般具有较大初始挠度,对结构的受力性能产生不可忽视的影响。线性稳定分析得到的临界荷载普遍较高,其应力水平高于材料的破坏强度极限,因此不宜作为此类结构安全设计的依据。本文对于均布轴向荷载作用下的压杆,考虑初始几何位移的影响,由幂级数法分析得出受力后的变形曲线,并根据边缘纤维屈服准则得到构件的理论最大荷载。对于一般工程构件,此承载力值低于根据线性稳定得到的临界荷载, 可以作为结构安全设计的依据。

BEARING CAPACITY OF THE COMPRESSION BAR WITH INITIAL DEFLECTION UNDER AXIAL UNIFORMLY DISTRIBUTED LOADS

Lattice form assembled structure has rather large initial geometric deflection that brings influence to its structural mechanical proprieties. The linear elastic theory can be used as a basis to judge the safety of perfect slender bar. But the critical load of lattice column obtaining from linear stability analysis is generally high. The corresponding critical stress is usually higher than the ultimate strength of material. So the critical force of linear buckling theory is not suitable to be as the safety design standard of such engineering structures. A compression bar bearing axial uniformly distributed load (containing self-weight) is studied in this paper. Considering the initial geometric deflection, the deflected curve is got by power-series solution. Furthermore, the theoretical ultimate load is obtained based on the yielding criterion of the cross-sectional edge stresses. The obtained bearing capacity is lower than the critical load by the linear stability theory for the engineering structures in practice so that the present work can be as the basic theory to the structural safety designs.