Geometrical nonlinearity of high aspect ratio wing arises from large tip deflection. This deflection then can no more be modeled by linear theories because of the geometric stiffening effect This large tip deflection not only effects the static characteristics like tip bending, tip twist, lift distribution over wing span but also on the dynamic characteristics like flutter, limit cycle oscillation and stability of aircraft. Static as well dynamic aeroelastic analyses need nonlinear structure and nonlinear aerodynamic modeling for high aspect ratio wing. In present work, strip theory has been used to model aerodynamic force while commercial FE package ANSYS has been used to model structure. Any structure can be modeled by considering its important mode shapes. Patil's high aspect ratio wing has been selected and modeled using shell and mass elements. In this model first three bending and 1st torsion modes are sufficient to simulate structure. Results are compared with published work and are in close agreement in tip deflection, tip twist.

static aeroelasticity; bending mode; torsion mode; modal analysis; high aspect ratio wing; nonlinear structure

Beihang University