基于有限元模拟研究不同形状磨料对高铝砖的冲蚀磨损

Erosion Wear of High Alumina Brick Impacted by Erodent Particles with Different Shapes Based on Finite Element Method

以石英砂、棕刚玉、碳化硅为磨料,对III等高铝砖进行常温垂直冲蚀磨损。假定磨料为动能相同的球体、正方体和正四棱锥,建立单粒子冲蚀模型对冲蚀试验进行有限元模拟,采用线弹性材料模型分析不同形状磨料的冲击行为,采用JH-2材料模型计算靶材的冲蚀磨损率和最大等效应力。结果表明:正方体和正四棱锥磨料的接触时间、垂直压入深度、冲击效率均相当,且远大于球体磨料;冲蚀磨损率的模拟结果和试验结果、靶材最大等效应力三者均与磨料圆度成反比,模拟结果略低于试验结果。对靶材冲蚀前后表面进行显微结构分析,钝角磨料(石英砂)的主要冲蚀机制是缺陷部位的断裂和基质的切削,尖角磨料(碳化硅)的主要冲蚀机制是骨料的断裂和基质的犁削。

The vertically-impacted solid particle erosion tests were carried out on a grade Ⅲ high alumina brick prepared with silica sand,brown fused alumina and silicon carbide at room temperature.An erosion model impacted by single particle with various morphologies of （i.e.,sphere,cube and regular rectangular pyramid） was proposed to simulate the erosion process based on finite element method.The kinetic energy for the particles with three morphologies obtained is the same.The erosion behavior of erodent particles with different morphologies was investigated for the line-elastic materials,and the erosion wear rate and maximum effective stress were determined for the JH-2 materials.It is shown that the contact time,vertical indenta tion depth and impact efficiency of abrasives with various morphologies like cube and regular rectangular pyramid are similar.The simulated and experimental erosion wear rates can be obtained,and the simulated erosion wear rate is slightly lower than the experimental value.The maximum effective stress of targets are inversely proportional to the circularity of abrasives.According to the microstructure analysis on the worn and unworn surface of targets,the erosion wear mechanism impacted by obtuse erodent particles （i.e.,silica sand） is the fracture of defects and the micro cutting of matrix,and that by the sharp erodent particles （i.e.,silicon carbide） is the fracture of aggregates and the micro ploughing of matrix.