对晶须添加的方向角效应进行了研究 ,对裂纹尖端后方晶须桥连角度引起的应力重新分配进行了有限元分析 ,得到晶须添加角度不同时Si3N4 陶瓷材料的裂纹尖端和晶须附近区域的应力应变场。分析表明 ,试件在Ⅰ型加载受力状态下 ,当添加晶须的轴向垂直于裂纹面时 ,晶须在裂纹尖端后方的桥接所引起的能量耗散作用最大 ,添加效果最优 ,使材料达到较好的增韧效果。当添加晶须与裂纹面法向形成角度θ时 ,随角度θ的增加 ,裂纹尖端拉应力增加。当添加角度较大时 ,晶须根部基体承受了较大的应力 ,易遭到破坏性崩裂。同时 ,晶须内部主应力与晶须轴向之间的角度也随角度θ的增加而增加 ,造成晶须折断 ,致使造成晶须拨出的体积分数 φap减小 ,降低了增韧效果 The direction angle effect of whisker addition was studied. The stress redistribution caused by the whisker bridging angle behind the crack tip was analyzed by finite element method. The crack tip and the vicinity of the whisker of Si3N4 ceramics were obtained when the whisker addition angles were different Stress-strain field. The results show that the energy dissipation caused by the bridging of whiskers at the rear of the crack tip is maximized when the whisker is axially normal to the crack surface under the loading condition of type Ⅰ, Material to achieve better toughening effect. When adding whisker and the crack surface normal angle θ, with the increase of the angle θ, the crack tip tensile stress increases. When the adding angle is larger, the whisker root matrix suffers greater stress and is apt to be destructively cracked. At the same time, the angle between the principal stress inside the whisker and the axial direction of the whiskers also increases with the increase of the angle θ, resulting in breaking of the whiskers, resulting in the decrease of the volume fraction φap of the whiskers and reducing the toughening effect