Experimental and numerical investigation of unbalanced boron/epoxy-aluminum single lap joints subjected to a corrosive environment

Abstract

The present study focusses on the experimental and analytical investigation of unbalanced Boron/Epoxy-Aluminum 2024 T3 single lap joints subjected to tensile loading, after being exposed to a corrosive environment (salt spray chamber) in order to study its effects on their strength and failure. FM94, high strength adhesive, was used for bonding. Different overlap lengths have been tested and an extensive experimental analysis has been executed. A geometrically nonlinear, two-dimensional finite element analysis has been employed to determine the hydrostatic stress and the shear strain distribution across the two interfaces of the single-lap joints, for four different overlap lengths. The results mainly prove that the overlap length and the aging conditions directly affect the joint tensile strength, while an optimum value of the overlap length can be defined. The maximum shear and normal stresses are found to increase as the overlap length increases, but the lap shear strength is not proportional to the overlap length. A good agreement between finite element results and experimental findings was found.

The Effect of Nanoparticles in Single Lap Joints Studied by Numerical Analyses

“…5a-c, it can be observed that stresses are symmetric about the center of the overlap and reach a maximum at the ends of the overlap [95], [96]. It should be noted that interfaces are also critical regions and must be studied deeply [89], [90].…”

“…That means, the area is mainly loaded in shear, especially as the overlap length increases. In other words, there is a large portion of the bond length which is mainly loaded in shear [89], [90].…”

“…1. The main objective is to transfer the load smoothly from one adherent to the other, while increasing the overlap length the maximum peel and shear stresses were minimized in the middle of the overlap region [89], [90].…”

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“…Although, both composite materials shown Fickian diffusion behavior with the mass increasing with the exposure time, until composites become saturated with water. Generally, moisture increases the flexibility and ductility of resin/adhesive [47] and decreases elastic modulus and strength [48][49][50][51].Therefore, it is not allowed to confer the high compression strength of carbon fiber composite. However, in certain polymers, positive moisture effect could be observed.…”

Comparison of different adhesively-bonded joint types for mechanical structures

“…A large number of authors presented studies on different joint configurations, and some of these are purely experimental. The study of Papanicolaou et al [20] focuses on an experimental and analytical investigation of unbalanced boron/epoxy-aluminium (2024-T3 alloy) SLJ subjected to a tensile loading, after being exposed to a corrosive environment, in order to study this effect on the maximum load (P m ) and failure mode. A high strength adhesive (FM94) was used for bonding and different L O were tested.…”