碳纤维复合材料-铝合金自冲铆接头成形规律及力学性能

Forming law and mechanical property of carbon fibre reinforced plastics and aluminum alloy self-piercing riveted joint

  • 摘要: 碳纤维复合材料在轻量化车身制造方面具有巨大的潜力和应用空间,而实现复合材料的有效连接则为一大挑战。采用自冲铆技术开展碳纤维复合材料和铝合金板材的连接工艺探索,总结了铆钉类型、冲铆速度和铆模尺寸对接头结构参数的影响规律,分析了冲铆过程中底切结构的形成机制,考察了不同板厚接头的强度性能及失效方式。研究发现,自冲铆接头底切值主要受到钉脚刺入下板深度及脚尖局部力矩作用的影响,且随铆钉有效长度、冲铆速度及铆模深度的提升而增加。通过工艺优化,碳纤维复合材料和铝合金板之间可得到成形结构良好的自冲铆接头,其机械内锁强度能够达到铝合金板接头的89%,而相同板厚时,复合材料自冲铆接头相比于铝合金接头的突出薄弱点在于其上板抵抗集中应力破坏的能力。

     

    Abstract: There are great potential and application space of carbon fibre reinforced plastics (CFRP) in lightweight vehicle body manufacturing, and realizing effective connection of the material is still a great challenge. The connection process between CFRP and aluminum alloy plate was explored using self-piercing riveting (SPR) technology, and the effects of rivet type, punching speed and riveting die dimension on joint structural parameters were summarized, then the forming mechanism of undercut structure in the riveting process was analyzed, the strength performance and failure mode of joints with various plate thicknesses were also investigated. It is found that the undercut value of SPR joint is affected by both the penetration depth of the rivet shank into the lower plate and the local moment on the rivet toe, and increases with the rise of the effective rivet length, the punching speed and the depth of the die. Through process optimization, SPR joints between CFRP and aluminum plates with good forming structure can be obtained, and the mechanical internal locking strength can reach 89% of that of aluminum alloy plates joint. However, compared with aluminum alloy joint with the same plate thickness, the outstanding weakness of CFRP joint is the ability of its CFRP upper plate to resist concentrated stress damage.

     

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