高温结构钢温度-应力耦合本构关系和梁单元的切线刚度方程

钢结构在高温下的强度和变形性能随温度和应力的耦合作用而变化。采用ECCS建议热膨胀系数、屈服强度和弹性模量确定双线性应力-应变曲线方程。高温下结构钢的变形分为瞬态应力变形、瞬态热应变和短期高温蠕变。在此基础上建立了温度—应力耦合本构关系及高温下的钢结构梁单元切线刚度方程,为钢结构的高温(抗火)分析提供合理的依据。

Temperature-stress coupling constitutive relationship of structure steel and tangent element stiffness equation for steel beam

The strength and deformation behavior of steel under high temperature are variable considerably due to the coupling action between temperature and stress.Based on thermal expansion coefficient,yield strength and elastic constant advised by ECCS,a two-lines stress-strain equation is established.The strain of steel at high temperature consists of transient stressing strain,thermal expansion strain and short-term creep.Then,a temperature-stress Coupling constitutive model and a tangent elemental stiffness equation for steel beam elements under high temperature condition is established.They can be used for thermal analysis or fire resistance of reinforced steel structures.