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

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 thickness and 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.Highlights Simplified quasi-static elastic Abaqus model identified the largest in-plane normal (axial and transversal) and shear interlaminar stresses; Four thin veils were used to validate interleaving strategies adopted; All laminates were produced using the same conditions to minimize process influence on experimental tests; Under low velocity impact (LVI) tests, interleaving laminates in the largest shear stress interlaminar can prevent external damage and mitigate internal damage up to 59%, comparing to the reference; No correlation between the veils and damage demonstrates the relevance of the interleaving strategy over the veil type. Strategic interleaving methodology to improve composite laminates' low velocity impact (LVI) damage resistance. image