基于数值模拟的碳纳米管水泥基复合材料导电机理分析∗

摘要

To analyze the conductive mechanism of carbon nanotube cement-based composites,the represent vol-ume element model of carbon nanotube cement-based composites was established.By fitting general effective media equation and calculating sensing property with finite element method,the relationship between volume resistivity and stress was obtained.The simulated results show that when the volume content of carbon nano-tube is 1.50%,the fitted value of the finite element numerical solution changes a little with the decreasing of the carbon nanotube diameter and the increasing of the aspect ratio.The observed behavior is because the value of 1.5vol% exceeds the percolation threshold and only contact conduction is considered in the finite element analy-sis.When the carbon nanotube content is from 0.31% to 1.33vol%,the sensing property of carbon nanotube ce-ment-based composites satisfies simmons tunnel effect universal equation.%通过建立碳纳米管水泥基复合材料的代表性体积单元模型，基于有限元法进行了有效介质方程导电模型的拟合和感知性能的计算，得到碳纳米管水泥基复合材料在荷载作用下的应力与体积电阻率的关系，在此基础上了分析了碳纳米管水泥基复合材料的导电机理.研究结果表明，碳纳米管体积掺量为1．50％时，随碳纳米管直径减小及长径比增大，有限元数值解的有效介质方程拟合值变化不大，这是因为1．5％的掺量已超过渗流阈值且有限元分析只考虑接触导电；当碳纳米管的体积掺量在0．31％~1．33％范围内时，碳纳米管水泥基复合材料的感知性能满足Simmons隧道效应普适方程.