Dynamic Analysis of Multi-Bolted FRP Composite Joints Using a Virtual Material Interface and Viscoelastic Behaviour

Abstract

The uses of Fiber Reinforced Plastic (FRP) composite materials have grown vastly in modern day engineering because they exhibit a greater strength-to-weight ratio, resistance to corrosion, and tailored mechanical properties. Bolted joints are commonly employed in FRP structures due to their ease of assembly and disassembly. However, their structural integrity and vibration performance directly affect the serviceability and safety of these structures. In this study, a three-dimensional (3D) numerical model is developed in ABAQUS, considering the frequency dependent complex moduli of composite materials and virtual material contact interfaceby user-defined subroutine UMAT, and has been used to model the dynamic responses of a single lap multi-bolted composite joint with varying bolt torque and support conditions using the elastic viscoelastic correspondence principle. The study systematically compares the joints with different torque levels, highlighting their influence on the modal properties. Results demonstrate that even a small change in torque and support conditions can significantly change vibration modes and modify the free vibrations characteristics. These multiscale modeling provide new insights into the dynamic analysis and design of engineering structures.