预应力混凝土受弯构件疲劳损伤全过程非线性分析

Full-range nonlinear analysis of fatigue damage in prestressed concrete flexural member

基于唯象观点对混凝土和钢筋分别采用疲劳弯曲受压变形模量和钢筋面积这两种宏观物理量作为损伤量度,在正截面应力分析的基础上,提出了一种考虑钢筋和混凝土两种材料耦合作用的非线性疲劳损伤全过程分析方法.该方法可以考虑由于组成材料损伤机制不同而造成的疲劳损伤过程中的应力重分布现象,并且适用于变幅重复应力作用的情况.通过分段线性的方法实现了混凝土构件的非线性损伤过程分析.计算结果表明,该方法能够较好地对预应力混凝土受弯构件进行疲劳全过程分析.

According to the phenomenological viewpoint, fatigue flexural compressive deformation modulus of concrete and area of reinforcement are considered as the damage parameters for concrete and reinforcement respectively. Based on the stress analysis of cross-section, a method for fatigue damage full-range nonlinear analysis of prestressed concrete beams that can account for the coupling action between concrete and reinforcement is proposed. This method takes account of the stress redistribution in the fatigue damage process caused by the difference between damage mechanisms of concrete and reinforcement, and is applicable to variable-amplitude repeated loadings. The nonlinear damage process is achieved by means of piecewise linearity. The calculation results fit favorably with the experimental results within the accepted limits.