Abstract
An experimental investigation of static and fatigue strength of double strap joints, using thermosetting and thermoplastic adhesives, between aluminum alloy 6061-T6 and carbon fiber metal laminate (CFML) has been carried out during this research. The static properties of joints, using thermosetting adhesives, were also determined while varying the temperature values. Two types of specimens were prepared: one, using YD-128 epoxy and the other using thermoplastic polyurethane by applying hand layup method. Results of both tensile and fatigue testing indicated better strength for thermosetting double strap joint both in elongation and fatigue cycles. For experimental validation of joints, finite element modeling has also been used during this research. Furthermore, the thermosetting double strap joint with maximum shear strength has been tested under a series of high temperatures. Temperature dependence of thermosetting epoxy adhesive indicated an increase in tensile strength of joint below the service temperature. However, a 50% drop in joint’s shear strength was observed when temperature was raised from 25°C to 60°C. Similarly, an increase in tensile strength of about 8.11% was observed at temperatures between −20°C to 25°C. The mode of failure for all combinations of thermosetting joints is mixed mode and cohesive failure whereas adhesive failure was observed for thermoplastics joints.
