Inverse Calculation of Timber-CFRP Composite Beams Using Finite Element Analysis

This study focuses on the flexural behavior of timber beams externally reinforced using carbon fiber-reinforced polymers (CFRP). Linear and non-linear finite element analysis were proposed and validated by experimental tests carried out on 44 timber beams to inversely determine the material properties of the timber and the CFRP. All the beams have the same geometrical properties and were loaded under four points bending. In this paper the general commercial software ANSYS was used, and three- and two-dimensional numerical models were evaluated for their ability to describe the behavior of the solid timber beams. The linear elastic orthotropic material model was assumed for the timber beams in the linear range and the 3D nonlinear rate-independent generalized anisotropic Hill potential model was assumed to describe the nonlinear behavior of the material. As for the CFRP, a linear elastic orthotropic material model was introduced for the fibers and a linear elastic isotropic model for the epoxy resin. No mechanical model was introduced to describe the interaction between the timber and the CFRP since failure occurred in the tensile zone of the wood. Simulated and measured load-mid-span deflection responses were compared and the material properties for timber-CFRP were numerically determined.