High performance and cost-effective hybrid steel/CFRP joints using bi-adhesive technique for the repair of metallic infrastructures

The use of the brittle adhesives commonly adopted in construction industry do not provide the best performance for steel structures. CFRP/Steel joint bonded with extremely tough adhesive achieve much higher strength and ductility. However, tough adhesives are not developed for the construction industry and their cost may question the...

Identifying interfacial failure mode in aerospace adhesive bonds by broadband dielectric spectroscopy

The most widely accepted test for bond durability analysis in aerospace metal-bonded structures is the bondline corrosion test introduced in the late 90s. Little progress has been made however on non-destructive testing methods that allow determining the bond quality after years of use. Here, a non-destructive method based on dielectric...

Effect of surface morphology on the Ti–Ti adhesive bond performance of Ti6Al4V parts fabricated by selective laser melting

Surface morphology of adherends is an important factor to take into consideration when studying and improving the performance of an adhesive bonded joint. In this study, the adhesion performance three different surface morphologies of Selective Laser Melted (SLM) Ti6Al4V was studied. The three surface morphologies were created by manufacturing...

Design of adhesively bonded lap joints with laminated CFRP adherends: Review, challenges and new opportunities for aerospace structures

Adhesive bonding is one of the most suitable joining technologies in terms of weight and mechanical performance for current carbon fiber reinforced polymer aircraft fuselage structures. However, traditional joint topologies such as single overlap joints induce high peel stresses, resulting in sudden failure and low joint strength when...

On the influence of overlap topology on the tensile strength of composite bonded joints: Single overlap versus overlap stacking

The goal of this study is to explore new topologies for adhesively bonded composite overlap joints in order to improve their strength under tensile loading. Multiple stacked overlaps, also referred as finger joints, are compared with single overlap topologies. The quasi-static tensile behaviour of single lap joints with two overlap lengths 12...

Co-cure joining of epoxy composites with rapidly UV-irradiated PEEK and PPS composites to achieve high structural integrity

Efficient joining of hybrid thermoset/thermoplastic composite joints is critical to produce high performance lightweight structures while keeping the cost low. Herein, a high-power UV-irradiation technique was proposed to rapidly active the surfaces of PEEK and PPS composites for the following co-cure joining with epoxy composites. A single...

The effect of bond-line thickness on fatigue crack growth rate in adhesively bonded joints

The effect of adhesive thickness on fatigue crack growth in an epoxy film adhesive (FM94) was investigated, using a combination of experiments and numerical modelling. For the range of thicknesses investigated an increased thickness led to an increased crack growth rate. It was found that the energy required per unit of crack growth did not...

Using acoustic emission to understand fatigue crack growth within a single load cycle

Current methods for prediction of fatigue crack growth are based on empirical correlations which do not take the crack growth behaviour within a single cycle into account. To improve these prediction methods, more understanding of the physical mechanisms of crack growth is required. In this research the acoustic emission technique was used to...

Susceptor-assisted induction curing behaviour of a two component epoxy paste adhesive for aerospace applications

The curing behaviour and the mechanical behaviour of susceptor-assisted induction-cured adhesively bonded joints has been investigated. Induction Heating (IH) was established by mixing Iron particles into a two component epoxy paste adhesive. The effect of different process parameters, such as particle content, coupling distance and coil...

Experimental and numerical analysis of a beam made of adhesively bonded tailor-made blanks

For aircraft structures, it is clear that the design and the selection of materials play an important role in the performance of the aircraft. The production costs are also important. The concept of tailor-made blanks (TMBs) is based on the use of dedicated blanks, made of different alloys and/or thickness in order to satisfy different demands...