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| 适用于几何非线性气动弹性分析的结构动力学降阶模型方法研究 |
| Study on structural dynamics reduced-order model for geometrically nonlinear aeroelastic analysis |
| 投稿时间：2022-05-20 修订日期：2022-07-05 |
| DOI： |
| 中文关键词: 几何非线性 降阶模型 极限环振荡 气动弹性 |
| 英文关键词:Geometric nonlinearity Reduced order model Limit cycle oscillation Aeroelasticity |
| 基金项目:国家自然科学(12172116),国家自然科学基金项目（面上项目，重点项目，重大项目） |
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| 中文摘要: |
| 几何非线性是壁板颤振、大展弦比机翼气动弹性等问题的一个主要特征,在进行数值仿真分析时往往需要采用商业非线性有限元求解器,存在计算量大、耦合迭代策略不易控制等问题。本文发展了一种适用于几何非线性的结构动力学降阶模型(CSD-ROM),利用广义坐标的非线性多项式表征非线性内力,采用参数识别方法获取多项式系数,并通过增加额外的线性模态来改善模型预测精度。基于此方法,分别针对壁板颤振、切尖三角翼的CFD/CSD-ROM非线性颤振问题开展了时域响应分析。计算结果表明,通过CSD-ROM计算出的壁板颤振速度为590m/s,颤振频率为174Hz,与有限元结果误差分别为0.8%、1.7%。马赫数0.879时切尖三角翼的颤振动压预测结果为2.25psi,与非线性有限元相比的误差为3.8%。本文采用的非线性和线性模态基底组合方法,在保证计算精度的基础上可有效降低训练样本数量,一定程度上可替代非线性有限元开展气动弹性分析。 |
| 英文摘要: |
| Geometric nonlinearity is one of the main characteristics of panel flutter and wing aeroelasticity problems with high aspect ratio, in numerical simulation analysis, commercial nonlinear finite element solvers are often required, which have many problems such as large computation and difficult control of coupled iterative strategy. In this paper, a structural dynamics reduced order model (CSD-ROM) for geometric nonlinearity is developed, the nonlinear internal forces are represented by nonlinear polynomials in generalized coordinates, polynomial coefficients are obtained by parameter identification method, and the prediction accuracy of the model is improved by adding additional linear modes. Based on this method, time-domain response analysis are carried out for the CFD/CSD-ROM nonlinear flutter problems of panel flutter and cropped delta wing respectively. The results show that the flutter velocity and flutter frequency calculated by CSD-ROM are 590m/s and 174Hz, respectively, with the errors of 0.8% and 1.7% compared with the finite element results. When the Mach number is 0.879, the predicted flutter vibration pressure of the cropped delta wing is 2.25psi, and the error is 3.8% compared with the nonlinear finite element method, the amplitude and frequency errors of limit cycle oscillation are within 11% in many working conditions. It shows that the method presented in this paper has good computational accuracy and can replace nonlinear finite element method for aeroelastic analysis to some extent. |
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