考虑翘曲变形的空间钢框架修正塑性铰模型

Modified plastic-hinge model for advanced analysis of space steel frames

为了推导一种既能反映塑性沿构件截面扩展,又能反映塑性沿构件长度方向(轴向)扩展的空间钢框架二阶非弹性分析模型,基于连续介质力学有限变形理论和更新的拉格朗日列式,横向位移采用考虑剪切变形的三次插值函数,扭转角位移采用Hermite三次插值函数以计入截面翘曲影响,结合塑性铰方法和简化塑性区模型,利用扩展的Orbison屈服面模型,提出了一种用于钢结构高等分析的修正塑性铰模型。该模型可用于各种空间钢框架结构的双重非线性分析,具有较强的通用性。最后通过算例证明了本文提出梁—柱单元的精度和有效性。

Based on the theory of continuous medium mechanics, and the updated Lagrangian formation, a modified plastic-hinge model is derived for the advanced analysis of space steel frames. Cubic polynomial interpolation functions considering shearing deformation and Hermite polynomial functions are adopted to describe the transverse displacements and torsion angles. With these functions, the warping effects can be considered. Combining plastic-hinge model with modified plasticzone method and using expanded Orbison＇s yielding surface model, a modified plastic-hinge method is derived by introducing elastio-plastic hinge parameter of element cross section and influence factor of axial deformation, which can be used to carry out dual nonlinear analysis of space steel frames. Numerical examples are presented to illustrate the validity and the universality of the proposed approach, and the results show that the new model is accurate and suitable for the nonlinear analysis of steel frameworks.