固粒击靶的有效摩擦系数  

EFFECTIVE FRICTION COEFFICIENT DURING PARTICLE IMPACT ON METAL

作　　者：陈大年[1] S.T.S.Al-Hassani 陈建平[1] 俞宇颖[1] 尹志华[1] 

机构地区：[1]宁波大学力学与材料科学研究中心,浙江315211 [2]Dept.of Mechanical Eng.UMIST Manchester,M60IQD,U.K.

出　　处：《工程力学》2004年第5期172-177,共6页Engineering Mechanics

基　　金：国家自然科学基金资助项目(19972058);浙江省自然科学基金资助项目(101007)

摘　　要：定义一种固粒击靶的有效冲击摩擦系数为粘着项与犁沟项的组合,其中包含表征剪切金属结合点的状态滑动或滚动的状态参数以及表征冲击物在击靶过程中产生犁沟效应的状态参数。研究表明,对于硬钢球斜冲击软钢靶情况,在连续滑移的情况下,只有在计及接触斑点的微粒间的相互作用的一定条件下,粘着项的值才可能接近0.05,这是Hutchings为使一系列数值计算的钢球反弹速度及角度与实验结果一致,在所有计算中所取的调节参数“摩擦系数”值。然而,研究表明,对于著名的Hutchings实验,如果连续犁沟发生,犁沟项则是冲击过程及初始冲击角的函数,就过程平均而言,其值大于0.05。由此,可认为,冲击过程中可滑移界面瞬间的滑移、滚动及犁沟状态的转化使Hutchings实验中的“摩擦系数”约为0.05;一般而言,这些状态的转化使固粒击靶的有效摩擦系数的过程平均值远小于低速简单滑移的摩擦系数。To study the friction coefficient during particle impact on metal, an effective friction coefficient is defined as a combination of shearing term and ploughing term at each instant. The state variables, which depend on the state of shearing the metallic junctions by sliding or rolling and the state of dragging the material from the front of the particle, are included. In the case of oblique impact of a hardened steel sphere against a mild steel target and continuous sliding of the sphere on the target, the value of shearing term could be near 0.05 only under certain condition of asperity interaction. It was chosen as an adjustable parameter in all of the calculations by Hutchings for consistency with both experiments and calculations. In the case of continuous ploughing, however, the value of ploughing term is a function of the impact process and the initial impact angle and is greater than 0.05 on an average for Hutchings?experiments. Therefore, it is suggested that the variation of sliding, rolling and ploughing state at each instant in the impact process make the coefficient of friction?equal to 0.05 for Hutchings?experiments. In general, the effective friction coefficient during particle impact on metal is far less than the friction coefficient during simple continuous sliding on an average.

关 键 词：固粒击靶 有效摩擦系数 剪切项 滑移或滚动 犁沟项 

分 类 号：O347.1[理学—固体力学]