引用本文: 邱智勇, 王轲. 基于模态振型的载荷转换计算方法. 力学与实践, 2023, 45(3): 607-614.
Qiu Zhiyong, Wang Ke. The method of load conversion based on the modal vibration pattern. Mechanics in Engineering, 2023, 45(3): 607-614.
 Citation: Qiu Zhiyong, Wang Ke. The method of load conversion based on the modal vibration pattern. Mechanics in Engineering, 2023, 45(3): 607-614.

## THE METHOD OF LOAD CONVERSION BASED ON THE MODAL VIBRATION PATTERN

• 摘要: 在航空领域，将翼面载荷准确施加到结构有限元模型上是有限元响应计算的必要步骤之一，但计算流体力学 (computational fluid dynamics，CFD) 得到的气动载荷通常无法直接施加至有限元模型。目前翼面载荷的转换计算方法依然存在计算效率不高的问题。由于翼面载荷分布具有连续、光滑的特点，理论上可用合理的基函数加权叠加进行拟合。本文试用模态振型作为基函数拟合载荷，先针对气动与结构两种网格构建同一翼面的两个结构模型，这两个结构模型理论上具有相同的模态。再用气动网格构建的翼面模型的模态振型作为基函数，并基于模态截断理论近似拟合CFD端的翼面载荷，得到拟合函数的权系数。最后，利用该权系数并根据结构网格构建的翼面模型的模态振型，拟合得到气动性能计算和有限元法（finite element method，FEM）端的翼面载荷。通过一个算例进行计算验证，以合力与压心来评价载荷转换的精度，结果表明，此法具有较高的计算精度与速度。

Abstract: 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.

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