分析了整体穿刺过程中纤维弯曲伸长机理，建立了钢针的力学模型，分别讨论了作用在针尖上的最大弯曲正应力、最大剪切应力以及穿刺阻力与针尖半径和针尖长度之间的关系，然后根据获得的结果对钢针针尖的形状进行了优化。

This paper analyzes the mechanism of fiber bending and elongation of integrated piercing process, and builds the mechanical model of steely needle, then discusses the increasing and decreasing relation between maximum bending stress, maximum shear stress and the resistance that acts on needlepoint and radius and length of needlepoint, then optimizes the form of needlepoint according to the result.