Aerothermoelastic Analysis of a Hypersonic Vehicle Based on Thermal Modal Reconstruction

Abstract

Hypersonic vehicles operate in a severe aerodynamic heating environment, which has a significant impact on their structural dynamic characteristics. Therefore, aerodynamic heating effects cannot be ignored when performing an aeroelastic analysis for a hypersonic vehicle. However, incorporating aerodynamic heating effects into the fluid-structural coupling analysis will result in extreme computational costs. Actually, after experiencing a sustained flight in a fixed state, the vehicle will eventually reach the thermodynamic equilibrium. Thus, the aeroelastic analysis can be efficiently performed by using the structural dynamic characteristics of the heated vehicle operating in each equilibrium state. The effects of aerodynamic heating show that the modal frequencies and modal shapes of the flexible structure are bound to change significantly in comparison with the unheated structure. In this paper, a method of thermal modal reconstruction is developed in order to directly generate the structural mode shapes and frequencies within the given parameter space without having to solve a high-fidelity thermal and structural problem. Once the modal data are available, the multivariate interpolation in a tangent space to Grassmann manifold is used to generate the modal matrix at the arbitrary selected parameter point. Besides, the Kriging interpolation method is used to establish the approximate relationships between natural frequencies and sampling points. Finally, an example of an aerodynamic heated control surface structure is used to validate the effectiveness of the proposed aerothermoelastic framework. It is demonstrated that the developed thermal modal reconstruction method has good robustness, very high computational efficiency, and sufficient accuracy over a wide parametric domain.

Flutter Optimization of Large Swept-Back Tri-Wing Flight Vehicles

“…Therefore, only 6 modes were used in the flutter ana Table 1 shows the frequencies of the first bend of the fuselage, the symmetric rotation o aileron, the anti-symmetric rotation of the aileron, the symmetric torsion of the aileron anti-symmetric torsion of the aileron, and the second bend of the fuselage. During flutter analysis, it is necessary to reasonably select the key mode shapes, so as to obtain an accurate judgment of the flutter modes [29]. There can be one or more combinations of different mode shapes from the frequency spectrum of the aircraft, which are the most likely relation to the lower critical flutter velocity [30].…”

“…Because the flutter mode consists of two or more modes, in order to further judge the flutter mode, the mode selection method was adopted to analyze the flight flutter behavior. During flutter analysis, it is necessary to reasonably select the key mode shapes, so as to obtain an accurate judgment of the flutter modes [29]. There can be one or more combinations of different mode shapes from the frequency spectrum of the aircraft, which are the most likely relation to the lower critical flutter velocity [30].…”

Calibrating hypersonic turbulence flow models with the HIFiRE-1 experiment using data-driven machine-learned models

“…Surrogate models have also been used in compressible aerothermodynamics (hypersonic flows), often to approximate temperatures, pressures and heating on wings and control surfaces [39,40]. They have been used within the context of aerothermoelasticity studies [41,42,43,44,45] or to design thermal protective systems [46]. In these surrogate models, the spatial variation of the fields are captured using POD bases, though a few studies have used kriging [41,40,45].…”

A Two-Level Optimization Method for Hypersonic Periodic Cruise Trajectory

“…Hypersonic vehicle generally refers to the aircraft flying at Mach number above 5 [1], which has a series of advantages such as high flight altitude, fast speed, and strong penetration ability, and it has a far-reaching impact on the development of aerospace technology in the foreseeable future [2]. Therefore, the research on hypersonic technology has been widely concerned by researchers all over the world [3,4].…”