超声速飞行器磁流变液夹层壁板振动与颤振特性研究

Study of vibration and flutter characteristics of sandwich panel with a magnetorheological fluid core in supersonic airflow

摘要:

现代超声速飞行器采用大面积蒙皮壁板以提升气动性能和隐身特性，然而在复杂恶劣的力学环境下，壁板发生颤振的风险日益增加。引入磁流变液夹层结构来提高壁板的颤振稳定性，并研究其在超声速气流中的振动与颤振特性。利用 MIN3 板单元结合考虑气流偏角的一阶活塞理论气动力建立三维磁流变液夹层壁板的气动弹性方程，在简支边界条件下，利用求解特征值方法，研究磁场强度、磁流变液层和上下表面层厚度、气流偏角等参数对壁板结构模态频率及颤振临界动压的影响规律。结果表明：磁流变液夹层壁板模态频率及颤振临界动压随磁场强度的增大而增大，但当磁场强度增加到一定值后，模态频率及颤振临界动压受磁场强度增大而减小；在磁场强度不变时，模态频率随磁流变液层厚度的增大而减小，随上表面层厚度的增大而增大；壁板颤振临界动压随磁流变液层厚度的增大先减小后增大，随上表面层厚度的增大而增大；在其他参数都不变时，夹层壁板的颤振动压随着气流偏角的增大而逐渐减小。

Abstract:

Modern supersonic aircraft employ large-area skin panels to enhance aerodynamic performance and stealth characteristics. However, in complex and harsh mechanical environments, the risk of panel flutter is increasing. This paper aims to improve the flutter stability of the panels by introducing a magnetorheological fluid (MRF) sandwich structure, and to investigate its vibration and flutter characteristics in supersonic airflow. The three-node mindlin plate element (MIN3) and first-order piston theory aerodynamic force with an airflow yawed angle have been employed to establish the aeroelastic equation of three-dimensional MRF sandwich panel. Under the simply supported boundary condition, the influence of parameters such as magnetic field strength, thicknesses of MRF layer and upper and lower surface layers, and airflow yawed angle on the modal frequency and critical flutter dynamic pressure of the sandwich panel is studied by solving the eigenvalue. The results indicate that the modal frequency and flutter critical dynamic pressure of MRF sandwich panel increase with the increase of magnetic field strength. However, when the magnetic field strength increases to a certain value, they will decrease by the increase in magnetic field strength. When the magnetic field strength is constant, the modal frequency decreases with the increase of the MRF layer thickness, and increases with the increase of upper surface layer thickness. The flutter critical dynamic pressure of the panel decreases first and then increases with the increase of the MRF layer thickness, and increases with the increase of the upper surface layer thickness. When other parameters remain unchanged, the flutter critical dynamic pressure of the panel gradually decreases with the increase of the airflow yawed angle.