Parametric study of load transfer in two-bolted single lap hybrid (bonded/bolted) shear joints

Abstract

A composite material can be defined as two or more materials combined to form another material with enhanced properties. A composite material shows high strength to weight ratio, light weight, tailored properties, high stiffness, high corrosion resistance and high fatigue life. In the recent past, the usage of composite materials in the aviation industry has been increasing and most of the lap joints are being used in aircraft fuselage. This study mainly focuses on the load transfer in hybrid (bonded/bolted) joints when they are subjected to tensile load. It is difficult to calculate the load transfer in hybrid (bonded/bolted) joints because of the difference in stiffness of the varied loads. A three dimensional Finite Element (FE) model has been developed to compute the load transfer in hybrid composite single lap joint. This model has been validated by comparing the results of FE model with experimental results for single bolted hybrid lap joint. A parametric study is done next to investigate the effects of various parameters such as material properties, tensile load, adherend thickness, bolt diameter and overlap length on load transfer by bolt. It is observed that hybrid joining (the combination of mechanical fastening and adhesive bonding) can provide enhanced structural performance, when compared to adhesive bonding. This study also discusses the modeling of contact between the bolt and hole and nonlinear material behavior of the model. The parametric study also quantifies relationship between the load transfer and adherend thickness, bolt diameter, tensile load, material properties and overlap length.