Impact analysis of embedded delamination growth in stiffener of hybrid laminated composite stiffened panel

Abstract

Modern aerostructures are predominantly of curved construction characterized by a skin and stiffeners. The latest generation of large passenger aircraft also mostly uses composite materials in their primary structure and there is trend toward the utilization of bonding of subcomponents. A stiffener is a simple beam attached to the skin to support the applied load. The stiffeners are provided to improve the bending stiffness of the panel which then improves the structural efficiency. Metals, unlike composites, offer plasticity effects to evade high stress concentrations during postbuckling. Under compressive load, composite structures show a wide range of damage mechanisms. A pre-damaged configuration is loaded to study the effect of delamination location and mode for delamination initiation and propagation. A parametric study is conducted to investigate the effect of the location of the delamination propagation when delamination is embedded inbetween plies of the stiffener, with the cases (i) delamination embedded at front and inbetween plies of the stiffener, (ii) delamination embedded at middle and inbetween plies of the stiffener, (iii) delamination embedded at the end and inbetween plies of the stiffener. Further, the influence of the location of the delamination in between plies of stiffener on load carrying capacity of the panel is investigated. The effect of delamination location on crack growth and collapse behavior is analyzed using analysis tool. The effect of delamination location on crack growth and collapse behavior is analyzed with numerical method of Virtual Crack Closure Technique.