Strength prediction of epoxy adhesively bonded scarf joints of dissimilar adherends

Abstract

In this study, strength of epoxy adhesively bonded scarf joints of dissimilar adherends, namely SUS304 stainless steel and YH75 aluminium alloy is examined on several scarf angles and various bond thicknesses under uniaxial tensile loading. Scarf angle, θ = 45º, 60º and 75º are employed. The bond thickness, t between the dissimilar adherends is controlled to be ranged between 0.1 mm and 1.2 mm. Finite element (FE) analysis is also executed to investigate the stress distributions in the adhesive layer of scarf joints by ANSYS 11 code. As the results, the apparent Young's modulus of adhesive layer in scarf joints is found to be 1.5 ~ 5 times higher than those of bulk epoxy adhesive, which has been obtained from tensile tests. For scarf joint strength prediction, the existing failure criteria (i.e. maximum principal stress and Mises equivalent stress) can not satisfactorily estimate the present experimental results. Though the measured stress multiaxiality of scarf joints proportionally increases as the scarf angle increases, the experimental results do not agree with the theoretical values. From analytical solutions, stress singularity exists most pronouncedly at the steel/adhesive interface corner of joint having 45º to 75º scarf angle. The failure surface observations confirm that the failure has always initiated at this apex. This is also in agreement with stress-y distribution obtained within FE analysis. Finally, the strength of scarf joints bonded with brittle adhesive can be best predicted by interface corner toughness, Hc parameter.

Numerical Analysis of Effect of Cohesive Parameters on Mixed-Mode Failure of Double-Scarf Adhesive Joint Subjected to Uniaxial Tensile Loadings

“…).Moreover, as mentioned before, the damage of the joint is a progressive process instead of a sudden transition [1][2][3]. Thus, the damage level D of the adhesive layer varies from 0 to 1 according to the evolution of the crack propagation [4,6].…”

“…From previous investigations, it is well known that the failure of adhesive joint, which is accompanied by the energy dissipates gradually at the crack tip, is a gradual process rather than a sudden transition [1][2][3]. In addition, the influential factors to the joint failure can be divided into two categories, the stress state of the adhesive layer and mechanical properties of the adhesive [4][5][6].…”

“…In addition, the influential factors to the joint failure can be divided into two categories, the stress state of the adhesive layer and mechanical properties of the adhesive [4][5][6]. For the interface stress state, it is decided by the geometrical configurations [2] and constraint effects [3] together.…”

“…Pardoen et al [2] analyzed the influential factors, such as the material properties and the geometry, on the responses during the wedge opening process through dimensional analysis. The results showed that the increment of the adhesive thickness will lead to the plastic dissipation increases.…”

Strength analysis of adhesive joints of riser pipes in deep sea environment loadings

“…Adhesive bonded joints are also widely used in riser pipes because of their light weight, high strength, and high corrosion resistance [1]. With the wide use of adhesive joints, many research works have been done to evaluate their strength including experimental and analytical methods [2][3][4][5][6][7][8].…”