Comparison of Beam and Shell Theory for Mass Estimation in Preliminary Wing Design

Abstract

This paper presents a comparison between the beam and shell theory for the application on wing box mass estimation in preliminary aircraft wing design. At first, the difference between the two theories in bending, in twist around the beam axis and in twist in flight direction is analyzed for a range of different wing geometries and load cases. In addition the differences in local and integral values of the x-normal, y-normal, xy-shear and von Mises stress are analyzed. Afterwards, certain geometries are selected and a realistic aerodynamic load is applied. For those wings a sizing of the skin and spar thickness is performed using both, the beam and shell theory. The sizing is performed with constant aerodynamic loads as well as with aeroelastic loads. Finally, explanatory statements for the differences in mass estimation and for different aeroelastic behaviour between both theories are discussed.