Investigating the Influence of FRP Layering Orientation on the Structural Behaviour of Timber Members

Abstract

This research adopts an integrated experimental and numerical approach to evaluate the structural performance of timber beams reinforced with carbon fibre-reinforced polymer (CFRP). A series of four-point bending tests were conducted on three configurations: unreinforced control, unidirectional CFRP-reinforced, and cross-ply CFRP-reinforced specimens. The experimental programme assessed deflection behaviour, peak load capacity, modulus of elasticity, and failure modes. Following the experimental phase, finite element analysis (FEA) was conducted using Abaqus to simulate the stress distribution and structural response under equivalent loading conditions. The comparative analysis between experimental and simulation outcomes offered insight into the modelling accuracy and the limitations associated with current adhesive and interface assumptions. The results demonstrated that cross-ply CFRP reinforcement significantly enhanced bending capacity, stiffness, and energy absorption relative to both the control and unidirectional specimens. However, discrepancies in peak load prediction were noted across configurations, underscoring the complexity of accurately modelling timber–FRP bonding interfaces—particularly when idealised assumptions are employed. The findings emphasize the crucial role of fibre orientation, bonding integrity, and material property representation in predicting the real-world behaviour of CFRP-reinforced timber. This thesis contributes to narrowing the gap between experimental understanding and practical implementation by offering data-driven insights into optimal CFRP reinforcement strategies for structural timber systems, particularly in applications requiring durability, energy dissipation, and enhanced flexural resilience.