Weight-Effect of Buckled Composite Stiffened Panels Under Static Compression

High strength-to-weight and stiffness-to-weight ratio materials, such as laminated composites, are advantageous for modern aircraft. With growing use throughout the industry, there is a need for high-fidelity digital tools to predict composite structure performance under compressive loading. Progressive damage analysis tools help enhance the industry’s understanding of damage initiation and growth mechanisms in composite structures while assisting in the design, analysis, and sustainment methods. A weight effect study was conducted on representative hat-stiffened panels to investigate the effect of varying skin thickness and hat design for the multi-stringer panel. Both single and multi-hat stiffened panels made of IM7-8552 carbon-reinforced epoxy were studied to identify optimal design solutions for initially pristine configurations. This work uses the Enhanced Schapery Theory to capture the effect of various damage mechanisms as the weight increases or decreases. The results suggest that for the configurations and loadings considered in this work, weight can be reduced by up to 16% and still avoid damage initiation reaching compressive loads up to two times because the damage is shown well into the post-buckled regime for the optimal configurations.