连接条件对GFRTP自冲铆接性能影响的数值研究

Numerical study of effects of joining conditions on performances of self-piercing riveted GFRTP

采用LS-DYNA软件建立玻璃纤维增强热塑性复合材料(GFRTP)的自冲铆接(SPR)有限元模型,对SPR过程进行数值模拟和实验验证。通过比较应力分布、钉腿张开度及接头强度,分析底座几何形状及铆钉材料对GFRTP工件SPR过程及接头强度的影响。研究结果表明:与金属SPR接头钉腿被下工件完全包裹而形成自锁结构不同,GFRTP工件SPR接头的形成机理是钉腿穿透下工件而向外翻卷,与钉头一起形成机械锁。连接条件对GFRTP工件SPR性能有显著影响。在一定范围内,增大底座凸台倾角有助于提高SPR的自锁性能;增加铆钉材料强度,可有效提升SPR接头的强度。

A finite element model of self-piercing riveting(SPR)of glass fiber reinforced thermoplastic(GFRTP)was developed based on LS-DYNA software.The SPR process was analyzed by numerical simulation and was validated by experiment.The effects of the die geometry and the strength of the rivet on the SPR performances of GFRTP workpieces were analyzed in terms of the stress distributions,the length of mechanical lock and the joint strength.The results show that the mechanism of SPR joint with GFRTP is different from that of metallic materials.The end of rivet leg for metallic workpieces is completely covered by the lower workpieces to form a self-locking structure;while for GFRTP workpieces the leg of rivet locks the workpieces together with the rivet head after it pierces through the workpieces and is warped outwards.The joining conditions have significant effects on the performances of SPR joints with GFRTP workpieces.Within a certain range,increasing the pip angle of die is useful for improving the self-locking performance of SPR joint,while increasing the strength of rivet can effectively improve the strength of SPR joint.