柔性飞机大变形状态飞行载荷分析

飞行载荷分析中综合考虑了结构大变形的几何非线性效应以及曲面气动力效应.飞机结构由相互连接的可以表征任意变形的几何非线性欧拉梁表示,升力面由展向以及弦向分布的涡环网格表示.计算时通过曲面网格动态跟踪结构的变形不断修改气动力影响系数矩阵,反复迭代求解气动力和结构变形直至结构变形收敛.给出了风洞试验机翼模型以及无约束定常平飞模型算例.计算结果表明:在小变形阶段该方法与线性计算方法的结果基本一致,非线性效应不明显;大变形阶段由于曲面气动力的非线性效应,计算结果与线性方法的有显著差别.分析表明该方法在大变形阶段的计算结果比线性结果更为合理,数值计算时间短,适合于工程快速分析.

Flight loads analysis of flexible aircraft under large deformations

A flight loads analysis framework was devised to consider the geometrical nonlinear effect and the surface aerodynamic effect for flexible aircraft. The structure consisted of joined nonlinear Euler beams allowing arbitrarily large deformations, while the lifting surface model employed span-wise and chord-wise vortex ring lattice. The core algorithms were to dynamically modify the aerodynamic influence coefficient matrix by the surface lattice associated with deformations, and to iterate the computation until the deformations converged. The proposed method was applied to two models. The results for small deformations agree with the linear method, whereas for large deformations, a significant variation has arisen due to the surface aerodynamics. This approach proved to be more accurate than the conventional linear method under large deformations, and feasible for engineering analysis.