钢-混凝土组合梁的非线性杆系有限元分析

The finite element analysis for composite beams of steel and concrete

根据截面应符合平截面假定等基本假设提出了预应力钢 混凝土简支组合梁全过程工作中钢梁下翼缘应力达到0.2fsy、钢梁下翼缘初始屈服、钢梁腹板下翼缘0.3hw高度处屈服及构件正截面破坏这4个特征状态的弯矩、曲率计算公式。基于这些特征点,运用最小二乘法分析得到组合梁截面弯矩 曲率关系的解析表达式。此外,利用该解析表达式建立了组合梁的有限元分析模型,推导了组合梁的单元刚度矩阵,编制了相应的非线性全过程分析程序。该方法考虑了混凝土压碎、钢梁材料硬化对结构性能的影响,计算简单,易于在计算机上实现,计算结果与实测结果较吻合。

A new method for nonlinear finite element analysis of composite beams of steel and concrete is presented. In this method, four key points in full work course of composite beams of steel and concrete and their formulas for moment and curvature are put forward. The four key points include the key point when the stress in lower wing of steel beam is up to 0.2, when the lower wing of steel beam yield, when yielding at 0.3 height above the lower wing of the web and when the section is crash. With the keypoints, the analytical expressions of moment-curvature relationship of composite beams can be got by least-squares procedure. By the analytical expressions, the model for finite element analysis and the element stiffness matrix are set up. The compute program for the nonlinear analysis is programmed, which can calculate the effect of the concrete crash and hardening of the material stiffness exactly. The method is easy to be programmed, the calculated results are in conformity with tested results.