Numerical Studies On The Battle Damage Repair Technique For Aircraft Panels

Aircraft structural battle damage repair technique, as one of the important contents of aircraft battle damage assessment and repair (BDAR) technique, has been drawn wide attentions by industrial and academic world. Especially, the battle damage repair (BDR) for aircraft panel, which acts as one of the main components of aircraft and so is prone to external damage, is very important. At present, the most studies on this aspect focus on single planar plates such as a cracked metallic plate at present, a metallic or composite plate with hole. Generally, The BDR for these structures adopts adhesive bonding patch repair and some computational models are used to solve this problem by finite element method (FEM), such as "twin plate-spring" model or its modified type, or three dimensional elements directly. Also, the BDR methods for stiffeners of aircraft panel have got less attention on literatures up to the present.This paper, based on the existing computational models and finite element method (FEM) technique, presents a model named "double shell-spring", in which the calculation of stiffness coefficients of spring element is simplified and rigid element is used to acts as the interface constraints. Based on the model and APDL of ANSYS software, the repair ultimate strength of single plate with various material properties is studied. Furthermore, the influence of adhesively bonded length and patch thickness on the repair ultimate strength of bonding patch repaired stiffener is calculated and analyzed. The repair ultimate strength of stiffened panel in which the battle damage is assumed locate on the stiffener is also calculated and analyzed. Some conclusions valuable in engineering are obtained in the paper from the results.