HIGH ENERGY WIDE AREA BLUNT IMPACT OF COMPOSITE AIRCRAFT STRUCTURES—PART A: DESIGN AND ANALYSIS METHODOLOGY OF REPRESENTATIVE SUBSTRUCTURE
Large test structures, common in the aerospace industry, offer a challenge to model, manufacture and test, with high cost associated with computational as well as materials, specimen fabrication, test planning/setup, and instrumentation resources. In this paper, a methodology is presented to demonstrate use of a smaller-sized substructure to produce equivalent response to the original, larger structure. The structure under study is a quarter barrel of typical commercial aircraft fuselage section made of carbon fiber reinforced polymer (CFRP), initially consisting of two circumferential structural members (C-frames and shear ties), and 12 stringers cocured to the skin. Through a series of finite element analyses and a modified specimen design, a substructure representing the quarter barrel was validated for loading conditions generated by high energy wide area blunt impacts (HEWABI) which are potentially caused by accidental contact from moving ground service equipment (GSE). The substructure is made of one circumferential member (C-frame and shear tie), and 6 stringers co-cured to skin and is shown to have similar stiffness and stresses in the region of interest. Finite element analysis (FEA) with progressive damage analysis demonstrates the equivalent response between the substructure and full quarter barrel. This methodology can be used in a wide range of applications, as long as the loading area is distant enough from the modified structure end and the correct boundary conditions/fixtures are defined to represent the omitted portions of the structure of interest.