Hybrid bonded-fastened joints and their application in composite structures: A general review

Hybrid bonding-fastening is an alternative joining technique that consists of simultaneous adhesive bonding and mechanical fastening of the adherends. In this paper, pertinent scientific publications are selected and reviewed in an attempt to synthesize the current knowledge on various aspects of this technique. A particular focus is maintained on its application in composite structures. Two major bonding-fastening methods, namely bonding-bolting and bonding-pinning, are identified and contrasted, and the characteristics of each are discussed. Existing gaps in the literature are identified. Finally, perspectives for future research are assessed. </jats:p

Application of natural fiber composites to musical instrument top plates

A flax-reinforced sandwich structure suitable for replacing wood in the top plates of string musical instruments was developed. The mechanical properties of Sitka spruce, the most widely used wood species for this application, were taken as a benchmark when the new materials were developed. The materials were characterized by static and dynamic methods to determine the dynamic Young’s modulus, shear modulus, internal friction, and static mechanical properties. Based on the material characterization, a hand lay-up process with a two-part closed mold and internal pressure bladder was developed and six prototype ukuleles were manufactured. The results show that the flax-reinforced sandwich structure can successfully act as a top plate and that an efficient manufacturing process can be developed to produce monocoque string musical instruments out of composite materials. </jats:p

Characterization of mechanical properties of randomly oriented strand thermoplastic composites

There is an emerging interest in the aerospace industry to manufacture components with intricate geometries using discontinuous fibre carbon/polyether–ether–ketone moulding systems (obtained by cutting unidirectional tape into strands). This type of material system is termed randomly oriented strand composites and is appealing for structural applications as it bridges the gap between the lack of formability of continuous fibre composites and the lack of performance of short fibre composites. The objective of this study was to investigate mechanical properties (tensile, compressive, shear and fatigue) of randomly oriented strand composites and to quantify the effect of strand size on their properties. Overall, properties were found to be highly variable and dependent on the strand length. Interestingly, tensile, compressive and shear strength had similar magnitudes and exhibited the same failure mechanisms (strand fracture and debonding). This experimental work expands the knowledge base for randomly oriented strand composite materials. </jats:p