<div style="text-align:justify;"> As a basic component of engineering fields such as aeronautics, astronautics and shipbuilding, panel structure has been widely used in engineering and scientific resea...<div style="text-align:justify;"> As a basic component of engineering fields such as aeronautics, astronautics and shipbuilding, panel structure has been widely used in engineering and scientific research. It is of great theoretical and practical significance to study the vibration of panels. The panel flutter problem has caused widely concerned by researchers at home and abroad during to the emergence of high-speed aircrafts. With regard to the eigenvalue problem of rectangular panels, it is generally believed that it is difficult to obtain a closed form eigen solution in the case of an adjacent boundaries clamped-supported or a free boundary that cannot be decoupled. Aiming at the problem, this paper studies the two-dimensional symmetric orthogonal laminated plate structure in the hypersonic flow in the thermal environment, and combines the first-order piston aerodynamic theory to study a high-precision separation variable method. Through this method, analytical solution to the closed form of the thermal flutter problem of rectangular panels can be obtained under any homogeneous boundary conditions. </div>展开更多
Spacecraft flexible appendages may experience thermally induced vibrations(TIV)under sudden heating loads,which in consequence will be unable to complete their intended missions.Isogeometric analysis(IGA)utilizes,in a...Spacecraft flexible appendages may experience thermally induced vibrations(TIV)under sudden heating loads,which in consequence will be unable to complete their intended missions.Isogeometric analysis(IGA)utilizes,in an isoparametric concept,the same high order and high continuity non-uniform rational B-splines(NURBS)to represent both the geometry and the physical field of the structure.Compared to the traditional Lagrange polynomial based finite element method where only C0-continuity across elements can be achieved,IGA is geometrically exact and naturally fulfills the C1-continuity requirement of Euler–Bernoulli(EB)beam elements,therefore,does not need extra rotational degrees-of-freedom.In this paper,we present a thermally induced vibration analysis framework based on the isogeometric method where thermal and structural behaviors are coupled.We fully exploited the higher order,higher continuous and geometric exactness of the NURBS basis with both benchmarks and sophisticated problems.In particular,we studied the thermally induced vibrations of the Hubble Space Telescope(HST)solar panel where main factors influencing thermal flutters are studied,and where possible improvements of the analytical reference methods are discussed.Additionally,thermally induced vibrations of the thin-walled lenticular tubes are studied and two new configurations of the tube are proposed to effectively suppress the thermally induced vibrations.Numerical examples of both benchmarks and sophisticated problems confirm the accuracy and efficiency of the isogeometric analysis framework for thermally induced vibration analysis of space structures.展开更多
The flexible attachments of spacecraft may undergo Thermally Induced Vibration(TIV)on orbit due to the suddenly changed solar heating. The unstable TIV, called thermal-flutter, can cause serious damage to the spacecra...The flexible attachments of spacecraft may undergo Thermally Induced Vibration(TIV)on orbit due to the suddenly changed solar heating. The unstable TIV, called thermal-flutter, can cause serious damage to the spacecraft. In this paper, the coupled bending-torsion thermal vibration equations for an open thin-walled circular cantilever beam are established. By analyzing the stability of these equations based on the first Lyapunov method, the thermal-flutter criterion can be obtained. The criterion is very different form that of closed thin-walled beams because the torsion has great impact on the stability of the TIV for open thin-walled beams. Several numerical simulations are conducted to demonstrate that the theoretical predictions agree very well with the finite element results, which mean that the criterion are reliable.展开更多
针对高超声速飞行器飞行过程中颤振边界变动范围大、试验测试难的问题,本文开展了考虑气动热效应的翼面结构地面颤振试验技术研究。首先基于工程法对结构所受的气动加热进行了分析,在此基础上开展了结构的热颤振特性评估并作为地面颤振...针对高超声速飞行器飞行过程中颤振边界变动范围大、试验测试难的问题,本文开展了考虑气动热效应的翼面结构地面颤振试验技术研究。首先基于工程法对结构所受的气动加热进行了分析,在此基础上开展了结构的热颤振特性评估并作为地面颤振试验结果的参考标准。考虑实际飞行中结构温升效应影响,建立了基于多工况点的气动力综合优化降阶算法,确保了整个温升过程的气动力模拟的精度。通过建立基于模糊逻辑比例、积分和微分(Proportional integral derivative,PID)控制的多点协调控制系统,实现了温升过程中时变系统的激振力控制器设计。最终搭建了地面颤振试验系统,按照典型飞行状态对结构的热颤振特性进行了测试,试验测试结果与仿真结果对比相对误差约10%。展开更多
文摘<div style="text-align:justify;"> As a basic component of engineering fields such as aeronautics, astronautics and shipbuilding, panel structure has been widely used in engineering and scientific research. It is of great theoretical and practical significance to study the vibration of panels. The panel flutter problem has caused widely concerned by researchers at home and abroad during to the emergence of high-speed aircrafts. With regard to the eigenvalue problem of rectangular panels, it is generally believed that it is difficult to obtain a closed form eigen solution in the case of an adjacent boundaries clamped-supported or a free boundary that cannot be decoupled. Aiming at the problem, this paper studies the two-dimensional symmetric orthogonal laminated plate structure in the hypersonic flow in the thermal environment, and combines the first-order piston aerodynamic theory to study a high-precision separation variable method. Through this method, analytical solution to the closed form of the thermal flutter problem of rectangular panels can be obtained under any homogeneous boundary conditions. </div>
基金Y.Guo would like to thank the National Natural Science Foundation of China(Grant No.11972187)and Priority Academic Program Development of Jiangsu Higher Education Institutions for their support.
文摘Spacecraft flexible appendages may experience thermally induced vibrations(TIV)under sudden heating loads,which in consequence will be unable to complete their intended missions.Isogeometric analysis(IGA)utilizes,in an isoparametric concept,the same high order and high continuity non-uniform rational B-splines(NURBS)to represent both the geometry and the physical field of the structure.Compared to the traditional Lagrange polynomial based finite element method where only C0-continuity across elements can be achieved,IGA is geometrically exact and naturally fulfills the C1-continuity requirement of Euler–Bernoulli(EB)beam elements,therefore,does not need extra rotational degrees-of-freedom.In this paper,we present a thermally induced vibration analysis framework based on the isogeometric method where thermal and structural behaviors are coupled.We fully exploited the higher order,higher continuous and geometric exactness of the NURBS basis with both benchmarks and sophisticated problems.In particular,we studied the thermally induced vibrations of the Hubble Space Telescope(HST)solar panel where main factors influencing thermal flutters are studied,and where possible improvements of the analytical reference methods are discussed.Additionally,thermally induced vibrations of the thin-walled lenticular tubes are studied and two new configurations of the tube are proposed to effectively suppress the thermally induced vibrations.Numerical examples of both benchmarks and sophisticated problems confirm the accuracy and efficiency of the isogeometric analysis framework for thermally induced vibration analysis of space structures.
文摘The flexible attachments of spacecraft may undergo Thermally Induced Vibration(TIV)on orbit due to the suddenly changed solar heating. The unstable TIV, called thermal-flutter, can cause serious damage to the spacecraft. In this paper, the coupled bending-torsion thermal vibration equations for an open thin-walled circular cantilever beam are established. By analyzing the stability of these equations based on the first Lyapunov method, the thermal-flutter criterion can be obtained. The criterion is very different form that of closed thin-walled beams because the torsion has great impact on the stability of the TIV for open thin-walled beams. Several numerical simulations are conducted to demonstrate that the theoretical predictions agree very well with the finite element results, which mean that the criterion are reliable.
文摘针对高超声速飞行器飞行过程中颤振边界变动范围大、试验测试难的问题,本文开展了考虑气动热效应的翼面结构地面颤振试验技术研究。首先基于工程法对结构所受的气动加热进行了分析,在此基础上开展了结构的热颤振特性评估并作为地面颤振试验结果的参考标准。考虑实际飞行中结构温升效应影响,建立了基于多工况点的气动力综合优化降阶算法,确保了整个温升过程的气动力模拟的精度。通过建立基于模糊逻辑比例、积分和微分(Proportional integral derivative,PID)控制的多点协调控制系统,实现了温升过程中时变系统的激振力控制器设计。最终搭建了地面颤振试验系统,按照典型飞行状态对结构的热颤振特性进行了测试,试验测试结果与仿真结果对比相对误差约10%。
