The investigation of viscoelastic mechanical behaviors of bolted GLARE joints: Modeling and experiments

The viscoelastic properties of bolted GLARE joints, which are rarely reported, also play a significant role in the mechanical performance, especially for long-term services. Glass fiber reinforced resin matrix composite layers of GLARE show temperature dependence and viscoelastic response in thermal environments. Thus, a novel viscoelastic model based on the spring-based method is proposed to predict the relaxation behavior of bolted GLARE joint in this work. The Maxwell–Wiechert model with n dashpots in parallel is introduced into this model, and the specific meaning of each parameter in the model is discussed in detail. This model is established to link the viscoelastic theory to the macroscale relaxation behavior of bolted GLARE joints, which matches well with the experimental results. It is observed that the long-term relaxation results of bolted GLARE joints under uniaxial tension deformation present obvious differences at different experimental temperatures illustrating that the relaxations of bolted GLARE joints have strong temperature dependence. Finally, the time-temperature superposition principle (TTSP) is incorporated into this model to predict the long-term relaxation effect on the bolted GLARE joints according to the relaxation experiments at different temperatures. This work provides a guideline for the design bolted GLARE joint used in the extreme environment for a long-term service.