THE METHOD OF LOAD CONVERSION BASED ON THE MODAL VIBRATION PATTERN

Within the aviation field, precisely applying the aerodynamic load of the airfoil to the structural finite element model could be a vital step for the restricted component response calculation. However, the aerodynamic load obtained by CFD (computational fluid dynamics) cannot be applied to the the node of the finite element model directly. At present, the conversion calculation method of aerodynamic load still has the problem of low calculation efficiency. Since the distribution of the aerodynamic load of the airfoil has the characteristics of continuous and smooth, theoretically, a reasonably weighted superposition of basis functions can be utilized to fitting. In this paper, the modal vibrations as the basis functions are used to fit the aerodynamic load. First, two structural models of the same airfoil for both aerodynamic and structural grids were constructed with the same modalities in theory. Then, the modal vibrations of the airfoil model constructed by the aerodynamic mesh are used as the basis function, and the aerodynamic load of the airfoil calculated by CFD is approximated based on the modal truncation theory to obtain the weight coefficients of the fitting function. Finally, the airfoil aerodynamic load which is based on the structural mesh is obtained by using these weight coefficients and fitting the modal vibration patterns of the airfoil model constructed from the structural mesh. An arithmetic example is used for computational validation to evaluate the accuracy of load transformation in terms of the combined force and the center of pressure. The results show that this method has high computational accuracy and speed.