Analytical Investigation on the Stress Distribution in Structural Elements Reinforced with Laminates Subjected to Axial Loads

The present paper investigates the stress distribution in structural elements reinforced with laminates and subjected to axial loads. The proposed analysis provides an analytical solution for the shear stress distribution between the substrate and the reinforcement, and for the normal stresses in the cross-section of the reinforcement. The stress analysis assumes a linear elastic mechanical behaviour of the adherents. The solutions obtained are applied to the problem of the elastic stability of a beam/column supported at its ends. The manifestation of the buckling phenomena leads to the failure of the structural element for loads lower than the characteristic strengths of the materials. In particular, the critical load represents the watershed value between the purely compressive and flexural behaviour of the element considered. In the case of stiff substrate, the buckling phenomenon leads to delamination of the reinforcement in the compressed area. Since buckling is an elastic problem, the stress distribution in the elastic range is used here to determine the value of the delamination length of the reinforcement at the critical load. In this way an analytical analysis which may be useful in the design phase of the reinforcement is proposed.