Mechanical Joining of Fibre Reinforced Polymer Composites to Metals—A Review. Part I: Bolted Joining

Abstract

As the fibre reinforced plastic composites gain larger and larger share in industry, the problem of joining them with metal elements becomes significant. The current paper is the first part of the literature review, which gathers and evaluates knowledge about methods suitable for mechanical joining of composite and metal elements. This paper concerns bolted joining, because this method of mechanical joining is widely used for joining composite materials. The paper describes failure modes of bolted joints in composite materials, the influence of the bolt clamping torque, the clearance between the bolt and the hole and aging on the performance of the joint, drilling techniques used in composite materials in order to minimize damages, different fastener types, inspection techniques, and finally, the techniques that have been developed in order to improve the strength of the bolted joints in composites. Since the hole drilled in a composite material in order to perform bolted joining is a weak point of the structure, those techniques: bonded inserts, titanium foil internal inserts, fibre steering, additional reinforcement, and moulded holes, mainly aim to improve the strength of the hole in the composite. The techniques have been discussed in details and compared with each other in the summary section.

Mitigation of Galvanic Corrosion in Bolted Joint of AZ31B and Carbon Fiber-Reinforced Composite Using Polymer Insulation

“…Bolting also provides good mechanical joint performance [ 13 ]. However, bolting requires a pre-drilled hole to assemble the materials, which can lead to damage on polymer composites [ 19 ]. To minimize the mechanical damage from hole drilling, selection of an optimum machining technique is critical.…”

Evaluation of Bonding Gap Control Methods for an Epoxy Adhesive Joint of Carbon Fiber Tubes and Aluminum Alloy Inserts

“…One of them is a bolted connection or riveted connection type, which is applicable for some cases. However, as discussed in a review [ 7 , 8 ], there are some downsides to this solution such as delamination during drilling of the holes, which could lead to failure of heavily loaded components such as wishbones discussed in this paper. Therefore, an adhesive connection will be used, since the axial forces present in the design will result in shearing of the adhesive bond, which is the optimum working direction of adhesive.…”

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

“…The joint used in a composite structure is usually the weakest point of the structure, and thus determines the structural efficiency [3]. A separate part of this literature review is devoted to the bolted joining of composite and metal elements [4], as it is the most widely used method of mechanical joining. However, the bolted joining of composite materials has several drawbacks, resulting mainly from the need of drilling holes.…”

“…Since none of those works either focus solely on the mechanical joining methods or cover all the developed methods of mechanical joining, and some of the joining methods have been omitted entirely, the current work presents a review which covers all the mechanical joining methods. The current paper along with its first part [4] provides a literature review which describes the level of development, and the advantages and disadvantages of mechanical methods of joining composite and metal materials. The current paper omits bolted joining, which is reviewed thoroughly in the first part of this review [4].…”

“…The current paper along with its first part [4] provides a literature review which describes the level of development, and the advantages and disadvantages of mechanical methods of joining composite and metal materials. The current paper omits bolted joining, which is reviewed thoroughly in the first part of this review [4]. The subsequent sections of the current work describe two methods of riveting used in composite materials: self-piercing riveting and friction riveting, method of joining by mechanical clinching, non-adhesive form-locked joints designed in order to introduce a concentrated force into a composite structure, pin joints which join the composite to metal by arrays of pins protruding from metal elements inserted into composite during curing process and loop joints which consist in entangling reinforcing fibres into loops protruding from metal elements.…”