Static Strength Evaluation of Composite Aircraft Wing for One-Wheel Landing Case

Composite materials have been extensively employed in aircraft due to their high specific strength compared to traditional isotropic materials. In this study, the wing of a two-seater trainer aircraft, constructed using the Just-in-time Pre-preg (JIPREG) fabrication process, has been designed and developed for static strength evaluation. The wing structure includes skins, a primary load-bearing spar, two shear attachment spars, and transverse ribs. The skins, spar webs, and ribs are constructed using a sandwich design, featuring foam cores and glass bi-directional fiber composites as face sheet materials. As part of a weight optimization effort, the thicknesses of various wing components were optimized based on strength and stiffness criteria. The optimized design was then assessed through finite element analysis (FEA) using MSC NASTRAN, focusing on a critical one-wheel landing load case to estimate strains and deflections—an essential scenario for evaluating the main landing gear fittings. Subsequent to the FEA, a full-scale static strength test was conducted on the wing to meet the Joint Aviation Requirements Very Light Aircraft (JAR VLA) standards. The FEA results, including strain and deflection responses, were compared with the test outcomes under vertical and drag limit loads applied at all four landing gear attachment brackets. This work provides a detailed examination of the FEA predictions and various aspects of the full-scale static strength testing, including the design of the test rig, data monitoring via strain gauges, deflection gauges, and load cells. The testing results showed a strong correlation with the FEA predictions, confirming the safety of the landing gear attachments under the one-wheel landing scenario. The wing’s bending strength was sufficient to support the limit loads without experiencing detrimental or permanent deformation in compliance with JAR VLA regulations.