MICROMECHANICAL MODEL FOR COMPOSITES REINFORCED BY LARGE VOLUMEFRACTION OF PARTICLES Ⅰ: ELASTIC ANALYSIS AND EFFECTIVE MODULUS
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摘要: 提出了一种高体积含量颗粒增强复合材料的细观力学模型。该模型将颗粒简化为同质、同尺寸的弹性圆球, 两颗粒之间的粘接材料(基体) 简化为连接颗粒的一段圆柱体, 假设了圆柱形基体中的细观位移分布形式, 在此基础上分析了一对颗粒之间弹性的细观应力场和细观弹性系数, 将颗粒对的细观弹性系数在空间各个方向上平均, 得到材料的宏观弹性常数, 并建立了宏、细观分析之间的联系。最后用本模型分析了一种实际材料(两种体积含量) , 弹性常数的预测与实验吻合良好, 研究还发现颗粒的空间分布方式对材料宏观弹性常数的影响不大, 而对细观应力的影响显著。Abstract: A micro-mechanical elastic analysis of composites reinforced by a large volume fraction of particles ispursued. A simplified microst ructure model has been suggested. The particles are assumed to be spheres linked byshort cylinders of mat rix material. The displacement component s are assumed to be linearly dist ributed along the axial direction of mat rix cylinders. Micro st resses and micro elastic constant s of a two-particle combination are first deduced for tensile and shear loading cases. Macro elastic constant s for the composite are then obtained by averagingthe micro elastic constant s in various special directions. Thus a relation between micro and macro analyses is const ructed. The model is applied to a metal mat rix composite with two different particle volume f ractions. The predicted elastic properties agree well with the experiment result s. The analysis also reveals that the effect of the particlepacking pattern on the macro elastic properties is t rivial ; however , the dist ribution of micro st resses in differentpacking patterns varies significantly.
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Keywords:
- particle reinforced composites /
- micro mechanics /
- average method /
- effective modulus
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