Comparative Study of Beam and Plate Theories for Moderate Aspect Ratio Wings

The main objective of the present study is to identify the best structural model for both aeroelastic and structural analysis of unswept rectangular wings with aspect ratios between 2 to 5. The paper presents a detailed study of the similarities and differences between the classical beam and plate theories, which provides new insight into this classical problem. To perform the aeroelastic analysis, the three-dimensional Peters aerodynamic model is coupled with classical plate theory. This combination leads to a new simpler three-dimensional aeroelastic model that can reduce the computational time. The results have been evaluated using both the unpublished and highly cited experimental data. Interestingly, by performing both structural and aeroelastic analyses, a comment can be stated that, even for relatively low aspect ratios (4 < AR < 5) of thin rectangular cantilever plates, the model based on the beam theory is closer to the experimental model compared to the plate theory. This finding may be unexpected by many researchers. Also, using a novel approach, it has been shown that the most significant difference between the beam and plate theories results arises from a subtle difference in the displacement field, which has not been given attention so far.