受损钢结构力学分析模型研究

Study on mechanical model for analysis of damaged steel structure

通过对8组不同受损程度的Q235钢材进行力学性能实验研究,分析了不同损伤程度对钢材二次加载和卸载时加载弹性模量和卸载弹性模量的影响,提出了受损钢材的力学模型。基于受损截面的应力-应变关系,通过定义受损受弯构件截面的无损高度比K,推导了不同受损程度下构件截面的平均弹性模量和损伤指标的计算公式。用转动弹簧来模拟受损截面的力学性能,根据受损微段的应力-应变关系,推导了受损截面的弯矩-转角关系和截面转动刚度计算公式,提出了可用于受损钢结构力学分析的计算模型。算例分析表明,截面受损降低了结构的刚度,在实际工程应用时不容忽视。

In order to study the influence of different damage degree of steel to its elastic modulus under its secondary loading and unloading, eight groups of different damaged specimens of Q235 steel have been tested, and the mechanical models of these kinds of damaged steel are put forward in this paper. Based on the relationship of stress-strain of damaged cross section, the calculation formulas of average elastic modulus and damage index of different damaged cross sections have been deduced by defining the damaged nondestructive height ratio K of the section. Simulating the mechanical properties of the section with a rotational spring, the relationship of M-6 and the calculation method of rotational stiffness of damaged cross section have been deduced according to the stress-strain relations of damaged micro segment of beam, and the calculation model which can be used to analysis damaged steel structure is presented. The results of calculations show that damaged section reduces the stiffness of structure,and it cannot be ignored in practical engineering.