Static strength of metal-composite joints with penetrative reinforcement

Abstract

a b s t r a c tA novel metal-composite joining technology is presented. Hybrid penetrative reinforcement (HYPER) uses small pins, protruding from the metallic part, to form an integrated assembly with high toughness. Different pin geometries and surface treatments are mechanically tested and compared. An ultrasonic, non-destructive inspection method is used to determine the failure modes. It is shown that the pins delay the initiation of failure, slow the propagation of damage and increase the ultimate strength by 6.5 times compared to an unpinned benchmark joint. The mean elongation at maximum load can be increased by over 400% and the energy absorbed can be more than 80 times higher, with reinforcement. Surface ''nano-structuring'' is also found to improve titanium-composite adhesion strength and consistency. Subsequently, a 25% higher load is required to initiate failure.

The effect of composite orientation on the mechanical properties of hybrid joints strengthened by surfi-sculpt

“…According to the comparison between joint L2 and reference joint (both of them have the same composite adherend design), surfi-sculpt can delay the onset of bond-line delamination, which is also observed in the research of similar hybrid joining schemes [5,7]. The reason is the surfi-sculpts are only 3 mm far to the metal end and relieve the stress intensity in the bond-line near metal end.…”

“…In this work, electron beam surfi-sculpt (EBS) makes protrusions on metal adherends through multiple relative movement between electron beam and the metal surface [1, 2] and form surfi-sculpts using the material of metal adherends, which is more flexible than other technologies, such as cold metal transfer (CMT) [3] and additive layer manufacture (ALM) [4]. Although limited researches on this joining technology have been reported on the field of mechanical properties and damage tolerance [3,[5][6][7][8][9][10][11][12], there is no study in the effect of composite design on joints' mechanical properties.…”

Fatigue behaviour of composite–composite joints reinforced with cold metal transfer welded pins

“…Moreover, metals allow to form pin shapes that are beneficial for the through-thethickness reinforcement, because they allow form-fit connections. While there is only limited literature available concerning the use of shaped metallic pins as joining reinforcement for CFRP to CFRP joints [16][17][18][19], there is additional literature available concerning joining reinforcements for metal to CFRP joints [21][22][23][24][25][26][27]. The main focus of these studies was the performance of the joints under monotonic loads.…”

Experimental and numerical studies on the braiding of carbon fibres over structured end-fittings for the design and manufacture of high performance hybrid shafts

“…The rough surface finish obtained from powder-based ALM-which in most applications is unwanted and requires post-processing steps-is advantageous in the case of hybrid joints as it increases the total surface area of the interface, which in turn improves adhesion [12,13].…”