A novel strategical approach to mitigate low velocity impact damage in composite laminates

Abstract

This paper describes a new interleaving methodology to improve composite laminates' low velocity impact (LVI) damage resistance. The approach relies on analyzing interlaminar stress in a conventional aircraft laminate to determine the appropriate interleaving strategy. A model was built to identify the larges interlaminar stress, and two interleaving strategies were defined, normal and shear stress. Four thin interleaving veils were used to validate strategies. Non- and interleaved laminates were submitted to LVI tests at 13.5, 25 and 40 (J) of energy. Despite interleaved laminates revealed an increase in thicknessnand resin volume fraction compared to the reference, they were limited to 10% and 7.6% on shear stress interleaved layups. Interleaved laminates also demonstrated an improved external and internal LVI damage resistance, especially when shear stress interleaving strategy was adopted, preventing external damage and mitigating internal damage up to 59%. No correlation between the veil's type and impact damage demonstrates the importance of interleaving strategies over the veil's characteristics.