A constitutive model based on the evolution and coalescence of elliptical micro-cracks for quasi-brittle materials

Damage and failure of quasi-brittle materials are caused by the evolution and coalescence of micro-cracks.To solve the problem of elliptical micro-crack growth at the elastic deformation stage,a method of complex potential functions is proposed and the effect of the initial orientation on micro-crack growth and deflection is discussed.The critical stress condition for the initial damage is derived according to the criterion of micro-crack growth.Based on energy conservation during wing-crack propagation,a damage constitutive model is developed with the strain criterion created in the condition of micro-crack coalescence.The stress-strain curves of quasi-brittle materials in uniaxial compression obtained based on this model are examined with the experimental results.

强动载作用下孔洞汇合对延性金属层裂损伤演化过程的影响

针对强动载作用下延性金属的层裂问题,在分析孔洞之间几何关联的基础上,定义了一个新的耦合损伤及孔洞几何信息的孔洞汇合判定方法,同时,基于能量守恒原理,解析了孔洞汇合对损伤快速增长影响的物理机理.通过分析数值计算结果和对比相关文献的实验可知:孔洞汇合后不仅引起损伤增长,而且导致了损伤材料内部微孔洞数目的减少、孔洞平均尺寸的增加。