Damage Repair Simulation of a Tension Panel and Pressurized Cylindrical Shell Using Adhesively Bonded Patches

Abstract

The bonded patch repair performance of a cracked tension panel, and a pressurized cylindrical shell with longitudinal through-crack, is simulated using a commercially available boundary element code. Three-dimensional, quadrilateral-shaped, reduced-quadratic order, boundary elements are used to model the panel, cylindrical shell, and repair patch. The adhesive layer is modeled using a continuously distributed system of linear springs. A special boundary element is used to model the crack. The tension panel analysis is based on a single-sided repair configuration. The relationship between crack length and stress intensity factor (SIF) for both the unrepaired and repaired panel is presented. The reduction in SIF and change in stress field, for the repaired panel compared to the unrepaired panel, determined from the present analysis, are compared with FME and analytical results. The occurrence of out-of-plane bending and its impact on the through-thickness SIF variation in the panel is discussed. Crack growth simulation results show the crack front becoming curvilinear as the crack advances below the patch. The reduction in SIF for a pressurized cylindrical shell with a double-sided elliptical patch repair is presented as a special case.