【摘要】 利用ANSYS有限元对梁柱三面受火无侧移单层单跨箱形钢柱组合框架受火后的性能进行数值模拟分析,得出了组合梁和钢柱温度场变化规律及框架受火后的变形和内力情况。分析表明:梁、柱沿截面高度、宽度方向均存在变化的温度场,温度梯度随受火时间的增加先逐渐增大后逐渐减小,且升温速度越快其最大值出现越早;三面受火的单层单跨箱形钢柱组合框架典型破坏模式为钢柱平面内对称屈曲破坏,破坏位置位于节点下部1.0~1.2倍钢梁高处;约束轴力是影响组合梁弯矩变化的关键因素。更多还原

【Abstract】 The behavior of a composite non-sway portal frame with steel box columns under international ISO 834 fire was analyzed by means of ANSYS FEM,the variations of member temperature distributions and internal force results were meticulously discussed.It was demonstrated that the member temperature at cross-sections was distributed nonuniformly and the temperature gradients varied with the firing time; the quicker the temperature increased,the earlier the gradient maximum appeared.Further it was revealed that the frame failed in the typical mode of symmetrical inplane buckling with plastic hinges located in the steel columns 1.0 ~ 1.2 times the beam height below the joints with beams.The bending moments of the composite beam were decidedly influenced by the constraint axial force developed in the beam during fire.更多还原