基于热/力试验的折叠舵连接刚度与颤振分析

Connection stiffness and flutter analysis of folding fin based on thermal-mechanical test

为了适装新型发射平台和进一步提高射程能力,高速飞行器需要采用折叠翼/舵的方案。高速飞行器面临的严酷高温环境和时变气动载荷条件,使折叠舵的结构动力学特性更加复杂,给开展折叠舵极端条件下热气动弹性特性的准确分析带来严峻挑战。本文构建了综合考虑温度、载荷、机构间隙和摩擦特性等因素的折叠机构力学模型,通过非线性有限元分析获得了不同因素影响下的连接刚度,并开展常温和高温试验验证研究。基于固有模态对结构进行降维简化,基于修正的三阶活塞理论建立了气动力模型,采用准定常模型对特定飞行剖面的颤振特性进行评估。基于Abaqus结构模型和STAR-CCM+气动模型,开展了时域响应分析。结果表明:常温和高温条件下,折叠机构转动刚度的计算结果与试验结果整体相对误差小于10%,具有较好的一致性,验证了模型的准确性和可用性;采用CFD与CSD耦合计算方法获得的临界颤振速度低于采用修正的三阶活塞理论结果,CFD/CSD耦合计算方法更加保守。本文建立的方法可为飞行器舵面颤振特性进行有效预示,对新型高速飞行器设计具有重要指导作用。

To adapt to the new launch platform and further improve the range capability,the scheme of folding wing or fin is used for high-speed aircraft.Severe conditions of high temperature and time-varying aerodynamic loads faced by high-speed aircraft make the structural dynamic characteristics of the folding fin more complex,and present serious challenges to accurate analysis of the aero-thermo-elastic properties of the folding fin.In this paper,a mechanical model of the folding mechanism is constructed based on a comprehensive consideration of the factors such as tem-perature,force load,mechanism clearance,and friction characteristics.The connection stiffness under the influence of different factors is obtained through nonlinear finite element analysis.The experiments at room temperature and high temperature are conducted for verification.The dismensionality of the structure is reduced for simplification based on natural modes.The aerodynamic model is by using the modified third-order piston theory.A quasi-steady model is used to evaluate the flutter characteristics of a specific flight profile.The Abaqus-based structural model and the STAR-CCM+aerodynamic model are coupled to analyze the time-domain response.The results show that at room tempera-ture and high temperature,the overall relative error of the rotational stffness of the folding mechanism between the simulated results and the test results is less than 10%,showing a good consistency and verifying the accuracy and us-ability of the model.The critical flutter velocity calculated by coupling CFD and CSD is lower than that calculated by us-ing the modified third-order piston theory.The method based on CFD and CSD is more conservative.The method pro-posed in this paper can effectively predict the flutter characteristics of the folding fin,and has important significance for the design of new high-speed aircraft.