Load case selection technique for combined modal finite element approach of high aspect ratio wing models

High aspect ratio wing is known to exhibit high deflection even though at relatively low aerodynamic loading, hence it is susceptible to geometric nonlinearity. Since an integration between the finite element analysis (FEA) of linear and nonlinear static solutions is a time-consuming process, therefore there is much effort to employ the nonlinear reduced order model (NROM) for computational efficiency. One of the options to enable this is by utilising the combined modal finite element (CMFE) approach. However, to date, there are limited guidelines on the generation of load cases to develop the NROM. Therefore, the present work comprehensively proposed a load case selection method as part of the CMFE procedure. The procedure is initiated with a normal mode selection and continued with loading profile selection technique either using individual or combined modes. The result found that the CMFE approach could predict the deflection with reasonable accuracy compared with FEA with small mean error and low standard deviation. The development of loading profile based on combined modes is exceptionally more accurate with relatively less computational time. Therefore, the proposed methodology can be considered as a way forward in developing NROMs via CMFE approach for future works related to highly flexible wing.