考虑界面应力时纳米涂层纤维增强复合材料的有效力学性能

EFFECTIVE MECHANICAL PROPERTY OF NANO COATED FIBER REINFORCED COMPOSITES DUE TO INTERFACE STRESS

基于Gurtin-Murdoch表/界面理论和广义自洽方法,获得了考虑界面应力时纳米涂层纤维增强复合材料有效反平面剪切模量的闭合形式解.讨论了涂层的壁厚、力学性能和界面性能对复合材料有效性能的影响.结果显示:在纳米尺度范围内,复合材料的有效反平面剪切模量受纳米涂层的尺寸影响显著.纤维体积分数一定时,涂层壁厚越大,纤维半径越小,有效反平面剪切模量与经典结果偏差越大.纤维刚度和涂层界面性能对复合材料有效模量的影响也取决于涂层刚度,非常软或非常硬的涂层都大大限制了纤维刚度对复合材料有效模量的贡献,过高的涂层刚度屏蔽了纳米复合材料表/界面效应的影响.

Based on the Gurtin-Murdoch surface/interface theory and the generalized self-consistent method,the closed-form solution of the effective anti-plane shear modulus of the nano coated fiber rein- forced composites is obtained. The effects of wall thickness, mechanical and interfacial properties of the coating on the effective property of the composites are discussed. The numerical results reveal that the ef- fective modulus is size dependent when the size of the coating is on the order of nanometer. For a fixed fiber volume fraction,the thinner the wall thickness is and the smaller the fiber radius is, the greater of the devi- ation from the classical results is. The influences of the fiber stiffness and coating interfacial property on the effective modulus are dependent on the coating stiffness,i, e. , a very soft or very hard coating can shield the contribution of the fiber stiffness to the effective modulus of composites,and a very hard coating shields the surface/interface effect of the nano composites.