PROGRESSIVE FAILURE ANALYSIS ON COMPOSITE SINGLE LAP BOLTED JOINTS USING XFEM

• Main Author: Anh Tuan, Nguyen
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/39247
• Institution: Institut Teknologi Bandung

The unrelenting passion of aerospace and automotive industry to enhance the performance of aircraft and automotive are constantly driving the development of improved high-performance structural material. Composites material are one such class of material that play a significant role in current and future aerospace and automotive component. One of the main attractions to composite materials is that they’re extremely lightweight, 30% lighter than aluminum and 25% the weight of steel. Carbon-Fiber-Reinforced plastic (CFRP) and Glass-Fiber-Reinforced plastic (GFRP) are usually used to make a component. Both of which are stiff and strong. Bolted joints are common mechanical fastened joint use for joining the composite part. It is unavoidable in complex structures because of their low cost, simplicity and facilitation of disassembly for repair. Bolted joints require holes in the composite structure. These holes cause large stress concentrations, decrease the load holding capacity and increase the complexity of the numerical analysis In this study, the composite CFRP woven fabric single-lap bolted joint is taken into account to analyze the failure mechanisms and failure load of composite structures. Experiments of single-lap bolted joints is conducted to study the progressive failure behavior of bolted joint structure. To validate experiment results, a traction – separation law is used as a constitutive model and is implemented within Extended Finite Element Method (XFEM) approach to predict bearing stress at failure and track the propagation of the crack. The approach is based on an assumption that damage in composite hole structure initiates and propagates from the hole in a selfsimilar fashion. To analyze the influence of parameters of composite plate on the failure, the three parameters to be considered are: width, thickness and stacking sequence. Effect of clamp-up torque in bolted joint also conduct to study the influence of this value to the strength of joint structure. Good agreement of bearing strength prediction of single-lap bolted joints can be seen at most of geometric configuration between experimental and simulation results (below 20 percent) and the bearing failure observed in experiments could not be treated in current study.