王培军, 李国强. 弹性轴向约束平面钢梁火灾下非线性分析的弧线坐标法[J]. 工程力学, 2008, 25(1): 137-144.
引用本文: 王培军, 李国强. 弹性轴向约束平面钢梁火灾下非线性分析的弧线坐标法[J]. 工程力学, 2008, 25(1): 137-144.
WANG Pei-jun, LI Guo-qiang. NON-LINEAR ANALYSIS OF ELASTICALLY AXIAL-RESTRAINED 2D STEEL BEAMS AT ELEVATED TEMPERATURES IN FIRE BASED ON ARC LENGTH COORDINATE METHOD[J]. Engineering Mechanics, 2008, 25(1): 137-144.
Citation: WANG Pei-jun, LI Guo-qiang. NON-LINEAR ANALYSIS OF ELASTICALLY AXIAL-RESTRAINED 2D STEEL BEAMS AT ELEVATED TEMPERATURES IN FIRE BASED ON ARC LENGTH COORDINATE METHOD[J]. Engineering Mechanics, 2008, 25(1): 137-144.

弹性轴向约束平面钢梁火灾下非线性分析的弧线坐标法

NON-LINEAR ANALYSIS OF ELASTICALLY AXIAL-RESTRAINED 2D STEEL BEAMS AT ELEVATED TEMPERATURES IN FIRE BASED ON ARC LENGTH COORDINATE METHOD

  • 摘要: 以变形后构件的弧线长度和截面转角为基本未知量,提出了一种火灾升温下弹性轴向约束平面钢梁的非线性分析方法。以节点的内力和外力平衡为条件建立基本方程,可方便考虑几何非线性和材料的非线性。节点仅包含弧线长度和截面转角两个自由度,计算效率优于常规有限元法的梁单元。以承受均布荷载的梁为例,分析了荷载、轴向约束刚度、沿截面和纵向不均匀分布温度的影响,给出了梁跨中的挠度、轴力和弯矩随温度的变化关系,并分析了在不同温度下跨中截面应变和应力的分布。算例表明,该方法有足够的精度。

     

    Abstract: A method is presented to study the non-linear structural behaviour of elastically axial-restrained steel beams at elevated temperatures in a fire, which employs the arc-length and section rotation of the deformed beam as basic variables. Governing equations are formulated based on the internal- and external-force equilibrium at every discrete node. This strategy can easily deal with the geometric non-linearity and elastic-plasticity of steel at elevated temperatures. Each node has two degrees of freedom in the proposed method. It is computationally more economical than the beam element in traditional finite element methods, which needs three degrees of freedom at each node. An example beam is studied using this method to verify the presented method. Parameters, including load-ratio, elastically axial-restrained ratio, transversely and longitudinally non-uniform distribution temperature, are studied. The middle-span deflection, axial force and moment, together with the strain and stress distributions across the section, are calculated at different temperatures. Comparisons to results obtained through general finite element method employing the shell element show that the presented method is precise.

     

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