钢-混凝土组合梁疲劳性能的有限元分析

目的为提高组合梁的抗疲劳寿命，研究组合梁疲劳性能．方法采用ANSYS软件包对组合梁的疲劳性能进行数值模拟与研究，通过建模对其施加疲劳荷载，计算具有不同配筋率和混凝土抗压强度的7根组合梁应力幅和疲劳寿命，得到了相应的s—N过程曲线，并与组合梁的试验结果和国际相关规范进行了比较．结果混凝土抗压强度从36．4MPa提高N41．8MPa，疲劳寿命提高了1．48倍；其他条件相同的情况下，应力幅提高9．9／MPa，试验和有限元计算疲劳寿命提高12．8万次和24万次．结论配筋率、混凝土强度和应力幅值是影响组合梁疲劳寿命的主要因素，配筋率比混凝土抗压强度影响更显著．

Finite Element Analysis on Fatigue Behavior of Steel-Concrete Composite Beams

In order to study the fatigue behavior of steel-concrete composite beams,ANSYS software packet was employed to simulate the behavior of steel-concrete composite beams under fatigue loads in this paper. After the finite element models were built for seven composite beams, which had different reinforcement ratio and concrete compressive strength, the stress amplitude and fatigue life were analyzed, then the relevant S- N curves were obtained, and a comparison was made among the experimental results, finite element analysis and related design codes. The results show that when the cubic strength increases from 36. 4MPa to 41.8 MPa,the fatigue life increases 1.48 times. Under the same conditions ,the value of the stress amplitude increases 9.9MPa, and the fatigue lives increase 128 thousand and 240 thousand cycles in terms of experimental results and analytical values respectively. The reinforcement ratio, concrete compressive strength and stress amplitude are the main influencing factors of the fatigue life for composite beams, and the reinforcement ratio has more apparent influence on the fatigue life than concrete compressive strength.