Formulation of a truss element for modelling the tensile response of FRCM strips

Modelling the tensile behaviour of Fabric Reinforced Cementitious Matrix (FRCM) is not a straightforward task due to the inner complexity of the mechanics of this kind of composite materials. In fact, after that the matrix is cracked, the compatibility between the fibre and the surrounding mortar is lost and the system behaves as two separate elements connected by a brittle interface. For this reason, several research studies proposed computational approaches for evaluating the tensile behaviour of FRCM composites, usually referring to brick-based 3D Finite Element Models (FEM) or to complex numerical procedures. This paper shows the formulation of a simplified coupled truss element for modelling the tensile behaviour of FRCM composites. The proposed element includes the interface slip between fibre and matrix and the brittle failure of the fabric and allows to describe the response of the system between the cracks in closed form. The proposed element is also adopted for assessing the tensile constitutive response of FRCMs through a simplified assembly procedure, proving to be reliable and computationally efficient.