Abstract The joining of fiber-reinforced plastics (FRP) currently poses particular process engineering challenges. Adhesive bonding or mechanical joining is normally used for such joints. However, bonding processes require complex measures for surface pre-treatment, fixing concepts and usually requires long curing times. On the other hand, mechanical joining processes such as screws or semi-hollow punch rivets lead to significant damage to the reinforcing fibers. Although different approaches for the production of plastic/metal hybrids are being pursued, there is still a need for a joining process that adequately meets the technical and economic challenges of joining metal and FRP. An innovative joining concept bypasses the problems of conventional joining techniques by using small-scale form-fitting elements in combination with established resistance welding processes. The investigations presented here include temperature measurements of the welds by means of contact thermocouples and analysis of the matrix material after welding by IR spectroscopy. The mechanical properties of the joint were verified in static shear tensile tests on coupon samples and in 3-point bending tests on geometries close to the component. The investigations carried out so far show high static bond strengths, which can be increased by coordinated welding parameters and component geometries. The joining process offers many possibilities with regard to the design freedom of the joining zone, since the pin structures can be flexibly adapted with regard to their arrangement, number and geometry, so that different requirements can be met. The Multi-Spot-Joint generates a quasi-ductile post-break characteristic. Thermal damage to the plastic matrix can be avoided by the targeted use of particularly short resistance welding processes. No damage to the plastic matrix could be detected during the IR spectroscopy.

中文翻译：

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用于生产 FRP 和金属混合部件的创新连接技术

摘要 纤维增强塑料 (FRP) 的连接目前提出了特殊的工艺工程挑战。粘合剂粘合或机械连接通常用于此类接头。然而，粘合过程需要复杂的表面预处理措施、固定概念，并且通常需要很长的固化时间。另一方面，机械连接工艺如螺钉或半空心冲压铆钉会导致对增强纤维的严重损坏。尽管正在采用不同的方法来生产塑料/金属混合物，但仍然需要一种能够充分满足连接金属和 FRP 的技术和经济挑战的连接工艺。一种创新的连接概念通过使用小尺寸的形状配合元件与既定的电阻焊接工艺相结合，绕过了传统连接技术的问题。此处介绍的研究包括通过接触热电偶测量焊缝的温度以及通过红外光谱分析焊接后的基体材料。接头的机械性能在试样的静态剪切拉伸试验和靠近部件的几何形状的 3 点弯曲试验中得到验证。迄今为止进行的调查显示出高静态结合强度，可以通过协调焊接参数和部件几何形状来增加。连接过程为连接区域的设计自由度提供了许多可能性，由于销结构可以灵活地调整其排列、数量和几何形状，从而可以满足不同的要求。多点接头产生准延展的断裂后特性。通过有针对性地使用特别短的电阻焊接工艺，可以避免对塑料基体的热损坏。在红外光谱分析过程中没有检测到塑料基体的损坏。