Finite element analysis of bending behaviour of glulam beams reinforced with CFRP plates

Abstract

Timber structures can effectively be reinforced using externally or internally bonded fibre reinforced polymer (FRP) composites. This paper presents numerical analysis of bending behaviour of glulam beams reinforced with carbon fibre reinforced polymer (CFRP) plates. Nonlinear 3-dimensional finite element model was developed and validated by experimental tests carried out on beams with CFRP plates strategically located in the tension zone between the bottom two laminations. The numerical analysis was performed using the software package ABAQUS. Glulam beams were modelled using solid elements, while membrane elements were used for CFRP plates. Suitable constitutive relations for each material were utilised in the model. The theory of anisotropic plasticity was applied to include plastic behaviour of timber laminations in the compression zone. The Hill’s criterion for orthotropic materials was used as a condition for transition to the plastic state. The progressive damage model was introduced to effectively tackle the softening behaviour of wood. The numerical results have shown good agreement with the experimental results in relation to load-deflection relationship, ultimate load and elastic stiffness. Nonlinear behaviour of reinforced beams was achieved in the numerical analysis, confirming the finite element model to be accurate past the linear-elastic range.