脆性材料轴向压缩破坏型式的理论分析

本文利用混合型裂纹扩展的能量释放率理论对脆性材料受轴向压缩时其内部微观裂纹的扩展规律进行了研究.研究结果表明,沿纵向裂开和沿斜截面剪切断开分别对应于能量释放率的二个极大值的方向.当端面摩擦较小时,由于沿纵向裂开为能量释放率最大值的方向,试件将发生纵向裂开的破坏型式.当端面摩擦较大时,由于端面摩擦将阻碍纵向裂纹的扩展,试件将沿斜截面断裂.利用本理论对于铸铁材料的计算结果与实验结果之间具有很好的一致性.

A THEORETICAL ANALYSIS OF THE BRITTLE MATERIAL FRACTURE UNDER AXIAL COMPRESSION

This paper presents a theoretical analysis about the propagation rule of the micro-crack in brittle materials under axial compression,based on the energy release rate criterion. The study indicates that the fracture in the axial ?section and the shear fracture in the oblique-section correspond to the two directions of energy release at its maximum. When the friction between the contact surfaces is reduced, the axial fracture takes place because in the axial direction the energy release rate gets higher. When the friction is increased, however, the shear fracture in oblique-section occurs since the axial propagation of the crack is prevented by the friction of the end surfaces. The theory shows good agreement with experimental results of materials of cast iron.