锌铝基复合材料球形粒子界面力学行为有限元分析

FINITE ELEMENT ANALYSIS OF MECHANICS BEHAVIOR IN THE INTERFACE OF PARTICLE FILLED ZINC-ALUMINIUM COMPOSITE

粒子填充锌铝基复合材料的破坏形式主要是界面脱粘及基体中裂纹的形成与扩展 ,研究粒子与基体界面附近的应力场分布情况 ,对分析材料的失效原因有一定帮助 ,对复合材料的设计、制备有指导意义。文中建立含裂纹球形粒子填充锌铝基复合材料有限元计算模型 ,采用线弹性轴对称有限单元 ,计算锌铝基复合材料球形填充粒子在拉压两种情况下粒子与基体界面处的应力场 ,定性讨论界面脱粘、裂纹形成与扩展的力学原因 ,并分析裂纹对应力场的影响。研究结果表明 ,在拉应力场作用下 ,粒子极区的第一主应力、法向应力最大 ,该处易脱粘 ,vonMises屈服应力在偏离极区 45°处最大 ,此处是塑变首先发生的区域 ;压应力场下vonMises屈服应力分布同拉应力场 ,但第一主应力很小 ,法向应力变为负值 ;裂纹对应力场的影响局限在裂纹所在的很小区域内 。

The major wrecking formation of particle-filled Zinc-Aluminium composite is the interfacial de-bonding and the crack forming and extending in matrix. The study on stress distribution near the interface of particle and matrix, is helpful for the analysis of material wrecking reason, and is of signification for the design and manufacture of composite. It is set up that finite element model which including crack in particle-filled Zinc-Aluminium composite. The stress distributions along interface in particle filled Zinc-Aluminium composite are studied by elasticity axis-symmetry finite element. Two cases are calculated which are tensile and compress stress. The interfacial de-bonding and the crack forming and spreading mechanical reason are discussed. The affect of crack on stress distribution is also analysis. The study results indicate that: In the case of tensile stress, the greatest first major stress and the divisor stress is at the pole of particle, where de-bonding often occur, and the greatest von Mises stress is at the 45° from the pole of particle, where plastic distortion occur in the first time. In the case of compress stress, the distribution of von Mises stress is the same as under the case of tensile stress, but the first major stress become smaller, and the divisor stress is of minus. The affect of crack on stress distribution localized at very small area where the crack is at, and the stress focus at the point of crack.