基于分形理论的高速压制粉末颗粒摩擦力分析

摘要

按Bowden和Tabor的原始处理,基于分形理论将总黏着摩擦系数表示为弹性及塑性区中的黏着摩擦系数的组合,建立了黏着摩擦系数的分形模型和粉末颗粒的内摩擦与分形维数的数学模型.通过函数曲线分析了粉末颗粒的分形维数对总的黏着摩擦系数、粉末颗粒的内摩擦力的影响.研究表明：对于一定的分形维数,总的黏着摩擦系数随归一接触面积的增大而急剧减小,粉末颗粒的内摩擦力随粉末颗粒的分形维数的增大和温度的升高而很快达到材料的塑性剪切强度值.%According to the original proposal of Bowden and Tabor and based on the fractal theory,the total adhesive friction coefficient is expressed as a combination of the adhesive friction coefficient in elastic and plastic regime.Then a fractal model of adhesive friction coefficient is proposed.And a mathematical model of the relationship of powder particles＇ internal friction and fractal parameter is built.Through the function curves,it is analyzed that the fractal dimension of the surface of the powder particle has impact on the total adhesive friction coefficient and the inner friction.The study shows that for certain fractal dimension,the total adhesive friction coefficient reduces sharply as the normalized contact area increases and the inner friction can reach the value of plastic shearing intensity rapidly as the fractal dimension and the temperature of the surface of the powder particle increase.