Modelling, analysis and simulation of hard body impact damge in laminated composite structures

Panels made with composites are used commonly, especially in automotive and aerospace structures due to their high strength/weight and stiffness/ weight ratio. Lateral impacts by hard body can cause delamination in significant amount, even though the external indication of damage may be a very small surface indentation. This type of damage is called as BVID (barely visible impact damage), and it can cause significant degradation of structural integrity (stiffness, strength, durability). In this paper, a computationally efficient finite element model is presented for predicting low-velocity impact damage in laminated composite structure impacted by hard body. Finite Element (FE) modeling is defined here as the material models with analyst's choice, elements, meshes, constraints, analysis procedures, governing matrix equations and their solution methods. For reviewing the analysis results pre and post processing options available in the chosen commercial FEA program for the intended analysis has been used. In the present case Abaqus/Explicit has been chosen for the analysis. The developed FE model is validated using benchmarks which are set of test results with known target solutions in the form of formulae, graphs and tables. The validated analysis procedure can then be applied with confidence to typical aircraft structures. The objectives of impact analysis are to determine (a) Impact damage resistance (contact force-time history), (b) Impact response (Impact displacement-time history),(c) Layer wise stress at specified instance of time, (d) Interlaminar stress,(e) Ply by ply impact damage(onset and growth, nature and extent),(f) Delamination onset. Significant results of this exhaustive study are graphically presented and discussed in this paper.