Experimental Modal Analysis of a Simple Rectangular Wing with Varying Rib’s Orientation

Three oriented rib profiles of a simple rectangular wing model were considered for the experimental modal analysis (EMA). They were namely the best individual, best parallel and best overall oriented rib profiles. The wing was setup as a cantilever-like condition with a roving hammer technique was employed for the testing. Modal properties with respect to natural frequency and mode shape were measured and the results were then compared against the baseline configuration. From the results, the impact towards the bending modes were found very minimal and can be negligible for all the considered oriented rib profiles. Nevertheless, significant increases in torsional frequencies was found for the best overall oriented rib profile when compared with the baseline configuration, showing that the wing becomes much stiffer in twisting direction without any increase in weight. Hence, this offer a possibility in flutter improvement or in weight reduction if the flutter performance to be kept similarly as the baseline configuration.