颗粒增强复合材料非理想界面刚度和有效模量的理论估计

采用内聚力模型(CZM)描述颗粒增强复合材料(PRCs)颗粒/基体非理想界面的力学行为,采用细观力学的Mori-Tanaka(M-T)方法和稀释解方法研究非理想界面刚度对该复合材料有效模量的影响。结果表明:复合材料某一体积含量下的有效模量和其颗粒/基体非理想界面刚度之间存在单调递增的关系曲线。同一复合材料不同体积含量的有效模量和非理想界面刚度关系曲线存在一个临界交点(CP),该点对应的临界界面刚度控制着颗粒体积分数对有效模量的影响。研究了基体和增强相的力学性能以及增强颗粒的尺寸对CP点临界界面刚度的影响。采用有效模量-界面刚度关系曲线,结合实验测得的有效模量,提出了估算PRCs的非理想界面刚度的方法,进而估计了复合材料的宏观有效模量。 

Theoretical estimation of imperfect interfacial stiffness and effective modulus in particle reinforced composites

The mechanical behavior of imperfect particle/matrix interface in particle-reinforced composites (PRCs) are defined by the cohesive zone model (CZM). Using mesoscopic mechanical Mori-Tanaka (M-T) method and dilute solution method, we studied the effect of imperfect interface stiffness on the effective modulus of composites. Results present that the monotonic increasing relation curves exist between the effective modulus and the particle/matrix imperfect interface stiffness for the composite with a certain volume fraction.The relation curves between the effective modulus and the imperfect interface stiffness with different volume fractions accounting for a certain composites converge to a unique critical point (CP), and the critical interfacial stiffness characterized by CP dominates the way of how volume fraction of particle affects the effective modulus. The effects of mechanical property of matrix and reinforcement phase, reinforced particle size on the critical interfacial stiffness of CP were studied. With effective modulus-interfacial stiffness relation curves and the experimental effective modulus, the estimated method of the imperfect interfacial stiffness for PRCs was proposed. The macro effective modulus of the composites was then predicted.