In multiphase particulate composites, the deviation and mismatch of the elastic moduli of different particles may significantly affect the overall mechanical performance of the composites. This study investigates the effects of such deviations on the macroscopic properties of multiphase composites via an iterative micromechanics-based method. The elastic properties of the particles are assumed to obey certain statistical distributions. In the proposed iterative method, the composites are divided into multiple two-phase composites and their strain concentration tensors are derived by means of the inclusion matrix-reference medium model, which is a modification of the generalized self-consistent method. Iterative solutions are established that take into account the effects of the variation in the elastic properties of the particles in terms of the effective shear and bulk moduli. The findings show that the proposed iterative method converges quickly and that the results agree well with the experimental data for three-phase composites. In addition, the model indicates that the variation in the elastic properties of the particles does have a significant effect on the effective moduli of the composites. (C) 2015 American Society of Civil Engineers.

本文将黄筑平等人提出的界面能理论应用于单向纤维增强的复合材料有效性质的计算中,给出了横观各向同性复合材料在考虑残余界面应力影响之后的五个独立的有效弹性参数以及有效热膨胀系数和有效比热。首先将单根纤维嵌于无限大基体中,利用不同的加载模式,求出了考虑界面影响的"等效纤维"的热力学性质。将传统细观力学模型中的纤维夹杂替换为"等效纤维",采用戴兰宏等提出的基于广义自洽模型的方法推导了有效横观剪切模量,其余四个有效弹性参数则通过复合柱模型得到。最后,通过两个联系有效热学性质与有效力学性质的方程,得到了有效热膨胀系数和有效比热。与其它考虑界面的文献不同,本文用界面能理论给出的预测结果将残余界面应力的影响也考虑了进来。

研究了含连通开孔饱和孔隙介质的有效力学参数,包括排水弹性模量、Biot张量和Biot系数。首先,采用以充满流体的连通孔隙为基体,取向随机的长纤维形固体骨架为夹杂的细观力学模型来表征饱和孔隙介质。通过令取向随机长纤维增强与球形颗粒增强复合材料的有效弹性模量相等,将取向随机的长纤维形夹杂等效为球形夹杂,并得到了相应的Eshelby张量。然后,利用排水时孔隙压力为常数的条件,结合Mori-Tanaka方法及修正的Eshelby张量,建立了流体体积模量的表达式,进而求出了饱和孔隙介质的有效排水力学参数。最后,数值算例表明本文预测结果与实验数据相符较好。

The stress and the debonding of the interface in coating layers structure due to thermal loading are investigated by using boundary element methods(BEM). The nearly-singular integrals that arise in the boundary integral equation(BIE) for such thin layered structures cannot be accurately evaluated us...

The debonding of particle/matrix interfaces has an important effect on the behavior of composite materials. During last decades, great efforts have been made to simulate the behavior of the interface. Boundary element method, as an alternative effective numerical method, has great advantages in simu...

In multiphase particulate composites, the deviation and mismatch of the elastic moduli of different particles may significantly affect the overall mechanical performance of the composites. This study investigates the effects of such deviations on the macroscopic properties of multiphase composites via an iterative micromechanics-based method. The elastic properties of the particles are assumed to obey certain statistical distributions. In the proposed iterative method, the composites are divided into multiple two-phase composites and their strain concentration tensors are derived by means of the inclusion matrix-reference medium model, which is a modification of the generalized self-consistent method. Iterative solutions are established that take into account the effects of the variation in the elastic properties of the particles in terms of the effective shear and bulk moduli. The findings show that the proposed iterative method converges quickly and that the results agree well with the experimental data for three-phase composites. In addition, the model indicates that the variation in the elastic properties of the particles does have a significant effect on the effective moduli of the composites. (C) 2015 American Society of Civil Engineers.