Failure analysis of high aspect ratio flexible wing aeroelastic loading

Abstract

Treatment of aerodynamics with structural dynamics is an interdisciplinary area and poses its added complexity when geometrical nonlinearities are considered while performing aeroelastic computation of high aspect ratio wing. Complexity is further added when failure criteria of composite materials are also studied under aeroelastic loading. This rear area in literature has been attempted in the present work. High aspect ratio wing geometry from the available literature has been considered. Strip theory, appropriate for 2D aerodynamics, has been utilized to model lift force. This theory considers geometry to be composed of elemental chord-wise “strips” and it assumes that the lift coefficient on each chord-wise strip is proportional to the local angle of attack. Downwash velocity at one elemental strip is assumed to be independent to that at adjacent strip. High aspect ratio wing structure has been modeled by considering first three bending and 1st torsion modes. APDL ANSYS code is written to perform analysis. MASS and SHELL elements have been used. Steady state deflection and twist are iteratively computed at each velocity value. Nonlinear static Aeroelastic loads are considered only. Failure criteria for bending and torsion are then used to check the integrity of the wing structure. Node positions are plotted on wing geometry indicating the failure under specified velocity value and specified laminate structure. This concept can then be extended to any geometry and any laminate structure.