高压油管接头Z-pin技术增强机理研究

Research on Z-pin Reinforcement of High Pressure Fuel Tube Joints

深油井复合材料高压油管轴向拉伸载荷大,螺纹接头部分易出现拉脱失效,为提高接头的连接强度,采用Z-pin技术增强最薄弱的螺纹连接部分。结果表明:在轴向拉伸载荷下,植入少量的Z-pin能显著提高螺纹接头的连接强度,改善各齿的应力分布,提高齿根部纤维层的层间剪切强度。基于试验观察和数据分析,深入研究了螺纹接头的破坏模式和Z-pin技术的增强机理,其增强机理是植入的Z-pin在层间裂纹处形成桥接区域,从而有效地的阻止了早期裂纹的扩展,提高了接头的破坏载荷。

There are very heavy axial tension in the casing under the deep well.An investigation on thread failure of the high pressure fuel tube joints is given in this paper,and it is a new idea that enhance the weakest connection thread jionts of Z-pin reinforcement.The results showed that the strength of the joints was improved obviously.Z-pin improved the stress distribution of the thread tooth on the axial tension loads,and raised the interlaminar shear strength.Based on visual and data analysis,this paper also studied on the failure mechanisms and the delamination toughening mechanisms of Z-pin reinforcement. Pullout of the Z-pin forms a bridging zone along the delamination that prevented the diffusion of the cracks.