Assessment of geometrically-nonlinear effects in aircraft loads

目前对飞机载荷的做法是基于线性结构动力学建模。对于相对僵硬的机翼来说，这是一个有效的假设，但随着机翼的展宽比变得更高，它无法捕捉到一些关键效果。它们包括机翼的几何刚性，气动力跟随变形几何的旋转，以及由于大的几何变化而引起的气动和惯性特性的变化等。为了调查这在未来更轻和更灵活的机翼设计中的相关性，该项目将解决以下问题：-开发能够在阵风和操纵载荷的复杂情况下纳入几何非线性的分析工具-在大展弦比机翼设计中计算有和没有几何非线性的载荷，包括对设计的主要影响的分析。分析方法应该应用于现有的飞机有限元模型，这些模型是为线性分析而设计的，并有效地捕捉由于大变形而引起的气动形状的任何相关变化。最后，该项目将对与非线性(时间域)分析相关的计算成本进行评估，并提出生成可用于生产的计算解决方案的战略

Current practice on aircraft loads is based on linear structural dynamics modelling. This is a valid assumption for relatively stiff wings, but it fails to capture some key effects as the aspect ratio of the wings becomes higher. They include the geometric stiffening of the wings, the rotation of the aerodynamic forces as they follow the deforming geometry, and changes on both the aerodynamic and the inertia characteristics due to large geometrical variations, among others. To investigate the relevance that this could have in the design of future lighter and more flexible aircraft wings, this project will address the following problems:- Development of analysis tools capable of incorporate geometric nonlinearity on complex for gust and manoeuvre loads - Computation of loads with and without geometric nonlinear on high aspect ratio wing design, including an analysis of the main implications on design.The analysis methods should apply to existing aircraft finite-element models, which are designed for linear analysis, and efficiently capture any relevant changes on the aerodynamic shapes due to the large deformations. Finally, the project will carry out an assessment of the computational costs associated to nonlinear (time-domain) analysis and propose strategies to generate production-ready computational solutions