Predicting Failure Loads of Impact Damaged Honeycomb Sandwich Panels - A Refined Model

Previous works [1] used nonlinear finite element models to investigate the effects of barely visible impact damage (BVID) in sandwich structures. Through a comprehensive numerical study it was found that sandwich honeycomb panels with BVID fail due to wrinkling or core crushing at significantly lower loads than undamaged panels. The critical load is controlled by the depth and size of damage, both of which control the foundation support and the resistance to wrinkles forming. In this article a simplified, closed-form analytical model is developed to predict critical stresses through a complete range of damage sizes and depths. This model extends previous work [1] by finding an expression for the critical wrinkling wavelength in a closed-form solution. A further expression is developed to account for rotational support at the edge of the damage site, as the wrinkle approaches the critical wrinkling wavelength. This article concludes by comparing numerical and analytical models against experimental values. Very good agreement is seen in all cases.