Some Studies on the Shimming Process for an Advanced Composite Structural Assembly of a Typical Fighter Aircraft

Abstract

Technologically advanced Fighter aircrafts of four and above generation use carbon newlinepreimpregnated composites of epoxy matrix material for primary Fighter aircraft structures newlinebuild like fuselage, wing and control surfaces for weight reduction, high specific strength, newlinearrest of crack propagation and desired operational performance like stealth features and newlineeasy to tailor parts due to product upgrades.However, it poses manufacturing challenges newlinearising out of part design requirement, assembly process, part manufacturing process and newlineother existing grey area of the composite material knowhow. newlineThe extensive study carried out and literature references have reflected that composite part newlinemanufacturing is a challenge for achieving of outer aerodynamic and inner contour within newlinedesign tolerance at part level and assembly stage. The existing wing assembly process uses newlinesuit on assembly method of shim preparation and bonding to the wing structure, hence the newlinemotivation of the research work is to eliminate the existing suit on assembly shimming newlinemethod, which is manual work affecting Fighter aircraft structure build quality as newlinereferenced in company internal documents of Manufacturing Process Sheet (MPS) and the newlinemanagement concern. newlineThis research work has studied on standard shim concept model which eliminates suit on newlineassembly of shims and the requirement of shims shall be known in advance before assembly newlinestage. The objective of the research is to design and experimentally validate the standard newlinecomposite shims of the required thickness for the gaps during assembly process of various newlinecomposite and metal parts. The research work is carried out with the collection and newlinemeasurement of shim gap data on Prototypes specimens of Left hand wing (LH), Right newlinehand wing (RH) and Naval prototype (NPR and NPL) of Fighter aircraft and further studied newlinethe pattern of shim thickness variation. Standard shim concept is used to know the standards newlineshim of various thickness, length and width requirement for the filling of gaps at wing newlineasse