Influence of Tool Shape on Hole Clinching for Carbon Fiber-Reinforced Plastic and SPRC440

Abstract

Carbon fiber-reinforced plastic (CFRP) is a lightweight material that can potentially replace structural steel components in automobiles. The hole-clinching process is a mechanical clinching technique for joining brittle or low-ductility materials, such as CFRP, with ductile materials. In this study, the influence of tool shape on the hole-clinching process for CFRP and SPRC440 was investigated using FE-analysis and experiments. The parameters of the tool shape investigated were the punch corner radius and the punch diameter. The geometrical interlocking shapes of hole-clinched joints were characterized by neck thickness and undercut. Based on the desired joint strength of 2.5 kN, hole-clinching tools were designed on the basis of the relationship between joint strength and geometrical interlocking. FE-analysis and hole-clinching experiments were performed with the designed holeclinching tools to investigate the geometrical interlocking shape as well as joinability, including neck fracture, undercut, and hole expansion, resulting from changes in tool parameters. Joint strength was evaluated to verify the effectiveness of hole clinching by a single lap shear test.

Mechanical Joining of Fibre Reinforced Polymer Composites to Metals—A Review. Part II: Riveting, Clinching, Non-Adhesive Form-Locked Joints, Pin and Loop Joining

“…This method was originally developed to join metal sheets including high strength steels and aluminium alloys [ 47 ]. It has been used in automotive [ 48 ]. Then, it has been extended to join many other materials including joining fibre reinforced composites to metal alloys [ 47 ].…”

“…The punch is positioned over the die cavity and it forces the metal component into the cavity ( Figure 9 b). The composite component can have a predrilled hole necessary to assure interlocking as it is presented in Figure 9 [ 46 , 48 , 50 ] or the hole can be punched during the clinching process [ 47 , 49 , 51 ]. The pre-cutting of the hole reduces the material damages compared to punching the hole in composite [ 51 ], however, it also adds additional step to the joining process.…”

Dissimilar Materials Joining of Carbon Fiber Polymer to Dual Phase 980 by Friction Bit Joining, Adhesive Bonding, and Weldbonding

“…Recently, extensive research has been conducted for joining carbon fiber composites to various metals (e.g., aluminum or magnesium alloys), using laser welding [7,8], friction stir blind riveting [9], friction spot joining [10][11][12], ultrasonic welding [13], adhesive bonding [14], friction lap welding [15,16], friction-based injection clinching joining [17], self-piercing riveting [18,19], and hybrid bonding (adhesive + mechanical fastening) [20][21][22]. In addition, very limited work has been focused on joining carbon fiber composites to steel [8,14,23,24]. However, the hole clinching and self-piercing rivet processes have been shown to be difficult to apply to AHSSs (σ TS > 780 MPa) [25][26][27].…”

Analysis of Failure-Mode Dependent Joint Strength in Hole Clinching from the Aspects of Geometrical Interlocking Parameters

“…Mechanical joining using forming technology, such as self-piercing rivets and clinching, has emerged as a remarkable technique for joining dissimilar materials because of its low-cost and high-speed fastening [10,11]. Hole-clinching is also one of the new joining methods using forming technology to join dissimilar materials, that are difficult or may even be impossible to apply by the conventional mechanical joining methods [12][13][14]. In hole-clinching, the geometrical interlocking is formed through a pilot hole made on low-ductility materials, as shown in Figure 1.…”