APPROPRIATE BOUNDARY CONDITION FOR FINITE ELEMENT ANALYSIS OF STRUCTURAL MEMBER ISOLATED FROM GLOBAL MODEL

Abstract

The wing of a fighter aircraft has various structural members which support aerodynamic and inertial loads, and transmit these loads to the fuselage. As a foremost step to evaluate the structural behaviour of the wing assembly, component contribution analysis is carried out. A finite element analysis of wing tulip of fighter aircraft isolated from the wing was performed under the design load case. Since aircraft wing is a statically indeterminate structure, reaction forces and moments at the supports depend upon the stiffness characteristics of the wing itself. In addition, stiffness of wing also affects the distribution of load and resulting deformation of the wing. These require that support structure of tulip isolated from the global wing model is represented by appropriate boundary conditions for the analysis. A comparative study for three boundary conditions (fixed support, nodal displacements and elastic support) was carried out to determine the representative boundary condition for the analysis of structural members isolated from the global model. It was found that elastic support represents the stiffness of the global model and is a more appropriate boundary condition for the analysis of local models which are isolated from a global model.