Experimental Determination of Stress Concentrations in Composite Laminates and their Effects on Damage Evolution

Abstract

Composite laminates are used for the construction of a wide range of products; from civil infrastructure to aeronautical or space structures. Since all these structures cannot be built at once, but they are composed by several structural elements connected in various patterns, the problem of stress concentrations strikes importantly. Additionally, the structures are often designed in a “fail safe” manner, which bespeaks the damage tolerance of the material. This means that the structural element and the structure are called to operate in the presence of various forms of damage. Damage locations within a structural element or a structure cause stress rising. In the present paper experimental investigation of the stress concentration arising in composite laminates, (a) around a circular notch and (b) due to damage onset and growth during their lifetime, is presented. The experimental results are compared to analytical model predictions.