Industrially Inspired Gust Loads Analysis of Various-Aspect-Ratio Wings Featuring Geometric Nonlinearity 机翻标题: 具有几何非线性的不同展弦比机翼工业阵风载荷分析

2020-02-10

This paper considers the effect of geometric nonlinearity on gust load analyses of high-aspect-ratio commercial aircraft. Three variants of a conceptual aircraft, featuring wing aspect ratios of 10, 18, and 26, are sized using an industrially inspired procedure to obtain realistic structures of existing and future designs. These aircraft are modeled in a nonlinear aeroelastic framework, featuring a geometrically exact beam formulation coupled with unsteady aerodynamics, and subjected to a gust loads process adapted for nonlinear systems. The gust analysis is also carried out using a linear approach (linearizing the equations of motion about an undeformed or trimmed geometry) to understand how nonlinearities influence the loads and dynamic behavior of aircraft as the aspect ratio increases. Load envelopes show that vertical shear and bending moments are predicted well by the linear analyses, even for the aspect-ratio-26 case, providing that the linearization is performed about the trimmed geometry. In contrast, the in-plane and axial loads are significantly underestimated using linear analyses. Torque behavior is problem specific and therefore difficult to generalize. Even on the aspect-ratio-10 case, which would traditionally be considered as a linear problem, it can be shown that the torque loads are considerably affected by nonlinearity.

考虑几何非线性对高展弦比商用飞机阵风载荷分析的影响。概念飞机的三种变型,机翼展弦比分别为10、18和26,采用工业设计的方法来确定尺寸,以获得现有和未来设计的真实结构。这些飞机是在一个非线性气动弹性框架中建模的,具有几何上精确的梁公式和非定常空气动力学耦合,并承受适应于非线性系统的阵风载荷过程。阵风分析也使用线性方法(线性化未变形或修剪几何体的运动方程)来了解非线性如何随着展弦比的增加影响飞机的载荷和动态特性。荷载包络线表明,即使在展弦比为26的情况下,只要对修剪后的几何结构进行线性化,线性分析也能很好地预测垂直剪力和弯矩。相比之下,使用线性分析法,显著低估了面内和轴向载荷。转矩特性是问题特有的,因此难以推广。即使在展弦比为10的情况下(传统上被认为是一个线性问题),也可以证明转矩负载受到非线性的很大影响。

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