轴压砌体随机损伤本构关系研究

Research on Stochastic Damage Constitutive Relation of Masonry Subjected to Axial Loading

基于砌体破坏机制,发展了相应的细观损伤单元模型,它由弹脆性的微弹簧和模拟裂缝滑移的塑性元件组成,轴压砌体可等效为细观单元的并联体.通过引入单元破坏应变分布随机场,推导了应力与损伤的均值、方差表达式.根据砌体单轴受压时的应力-应变全曲线试验结果,结合随机建模原理和优化算法确定随机场参数和材料参数,将分析得出的受压随机应力-应变关系与试验结果进行比较,二者吻合良好.

Based on the features of the masonry, the meso-damage element which comprised the elastic part and the plastic part was introduced. Furthermore, a new kind of idealized damage model, in which the material was represented by a set of elements of equal stiffness that were joined in parallel, was developed for masonry subjected to monotonic axial compressive loading. Considering damage and elasticity modulus as random variables, stochastic equations of damage growth and stress-strain were presented. With the help of stochastic structural modeling and optimization methods, coefficients in the model, e.g. the distribution parameter of the random field of failure strain, could be easily determined by the full stress-strain curves of axial compression of masonry specimens. Comparing with existed test results, it was found that the analytical values had a good agreement with experiments.