韧性金属Kaiser效应方向独立性的实验研究

Experimental Study of Kaiser Effect Direction Independence in Ductile Metal

Kaiser效应是声发射技术实际应用的理论基础。本文以韧性金属材料Q345不同方向拉伸实验为例,探究力的方向对韧性金属Kaiser效应的影响。实验结果表明,韧性金属材料在某一方向加载时,表现出了Kaiser效应;当改变加载方向时,呈现出与第一次加载方向类似的声发射特性,说明声发射现象对其他加载方向上所承受的最大载荷不具有记忆的能力,而仅与该方向承载历史有关,即韧性金属Kaiser效应与力的方向性间具有独立性。同时,利用细观损伤理论对这一现象产生的机理进行了定性的解释。

Kaiser effect is the theoretical basis of acoustic emission（AE）technique practical application.In this paper,multidirectional tensile experiment of Q345 ductile metal was conducted to explore the relationship between force direction and Kaiser effect.Experimental results show that Kaiser effect presents when ductile metal is loaded along one direction.When loading direction is changed,AE characteristic is similar to that of the first loading direction,which illustrates that AE phenomenon does not have the ability to remember the maximum load along the other direction and is only related to the bearing history along this direction.In other words,Kaiser effect of ductile metal is independent of the force direction.At the same time,in this paper,the mechanism of this phenomenon is explained qualitatively based on mesoscopic damage theory.