Equivalent Asymmetric Bernoulli-Euler Beam for Aeroelastic Ground Vibration Test Model

Abstract

One of the challenges associated with aeroelastic stability of air vehicle is to develop or adjust finite element model (FEM) to the result of ground vibration test (GVT) prior to flight flutter test as required by air vehicle requirement. Directly adjusting huge degrees of freedom of detailed FEM model is usually not recommended due to the large number of variables to tune. In the present paper, an indirect approach is presented to find FEM beam model which is equivalent to the detailed FEM model. To better represent the structure required for aeroelastic analysis, the proposed FEM beam model is developed to handle bending properties of asymmetric cross section as well as torsional properties. Since the resulting equivalent beam model is much simpler than the detailed FEM model, therefore it is easier to adjust to the GVT result. Validation of the method by comparing to NASTRAN result is presented and shows a good agreement. The results show that the present procedure gives an analytical solution for a Bernoully-Euler type beam.