Wing Fuselage Butt Joint Design

The design of wing-fuselage connection joint is one of the major parts in an aircraft design. The quality of the joints plays an important role in the safe operation and performance of an aircraft. The purpose of this paper is to investigate and design a interconnection joint between fuselage airframe and major wing spar for an improved version of certain type of aircraft. Although traditional load factors had been introduced in the determination of external loads imposed on the joints, the author still suggested the safety factors based on reliability analysis should be used, with a review of the concept of load factors and their history of developments. Numerical analysis has been firstly made on the original joint design by means of the software CATIA and PATRAN/NASTRAN, which served as the basis of the design and analysis of the new joints. Be aware of the restriction that overall change can not be made on the structural configuration ,and based on the requirement of structure design ,the author suggested two kinds of modifications -enhanced plan and improved plan for the new joint design. Much effort was made on the design consideration and 3D solid modeling of the joints. Each calculation reaches up to 70 thousands solid elements and over 20 thousands nodes. According to analytical results, both design schemes were compared each other on the dimensions, weight, stress level, fitting and outer shape, and both schemes have shown improvements to certain extent about the original design. In addition to the static strength analysis, of the fuselage frame relevant to the joint was also evaluated by crack propagation analysis.