Thermostructural concepts for hypervelocity vehicles

Shih, Peter K.; Prunty, Jack; Mueller, Richard

doi:10.2514/3.46032

Cited by 19 publications

(9 citation statements)

References 4 publications

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“…7 and 8, respectively. A survey of the literature revealed a wide range of design strategies for mitigating the high temperatures experienced in hypersonic flight [53][54][55][56][57][58][59][60]. This study considers a TPS consisting of an outer heat shield and middle insulation layer on top of the structure, as shown in Fig.…”

Section: Control Surface Modelmentioning

confidence: 99%

Reduced-Order Aerothermoelastic Framework for Hypersonic Vehicle Control Simulation

Falkiewicz¹,

Cesnik²,

Crowell³

et al. 2011

AIAA Journal

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Hypersonic vehicle control system design and simulation require models that contain a low number of states. Modeling of hypersonic vehicles is complicated due to complex interactions between aerodynamic heating, heat transfer, structural dynamics, and aerodynamics. Although there exist techniques for analyzing the effects of each of the various disciplines, these methods often require solution of large systems of equations, which is infeasible within a control design and evaluation environment. This work presents an aerothermoelastic framework with reducedorder aerothermal, heat transfer, and structural dynamic models for time-domain simulation of hypersonic vehicles. Details of the reduced-order models are given, and a representative hypersonic vehicle control surface used for the study is described. The methodology is applied to a representative structure to provide insight into the importance of aerothermoelastic effects on vehicle performance. The effect of aerothermoelasticity on total lift and drag is found to result in up to an 8% change in lift and a 21% change in drag with respect to a rigid control surface for the four trajectories considered. An iterative routine is used to determine the angle of attack needed to match the lift of the deformed control surface to that of a rigid one at successive time instants. Application of the routine to different cruise trajectories shows a maximum departure from the initial angle of attack of 8%.corresponding to ith column of A C = correlation matrix c = modal coordinate of thermal proper orthogonal decomposition basis vector Cx = correlation model for kriging c p = specific heat at constant pressure d = structural modal coordinates, kriging sample point E = modulus of elasticity F = thermal load vector of full system in physical space f = generalized thermal load vector of reduced system in modal space F s = structural load vector of full system in physical space f s = generalized structural load vector of reduced system in modal space H i = coefficient matrices for integration of equations of motion h i = thickness of ith layer of thermal protection system K = thermal conductivity matrix of full system in physical space k = generalized thermal conductivity matrix of reduced system in modal space K G = geometric stiffness matrix K s = structural stiffness matrix k s = generalized stiffness matrix of reduced system in modal space k T = thermal conductivity of material K s = modified structural stiffness matrix L = aerodynamic lift, length M = thermal capacitance matrix of full system in physical space, Mach number m = generalized thermal capacitance matrix of reduced system in modal space M s = structural mass matrix of full system in physical space m s = generalized mass matrix of reduced system in modal space n = number of proper orthogonal decomposition snapshots n e = number of snapshots for kriging evaluation cases n k = number of kriging snapshots n s = number of structural parameters in reduced-order aerothermodynamic model n t = number of thermal parameters...

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Section: Control Surface Modelmentioning

confidence: 99%

Reduced-Order Aerothermoelastic Framework for Hypersonic Vehicle Control Simulation

Falkiewicz¹,

Cesnik²,

Crowell³

et al. 2011

AIAA Journal

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“…Structural components have played a major role in the development and design of hypersonic vehicles [7,[30][31][32][33][34][35][36][37]. The structure experiences high-temperature gradients and intense pressure and heat loading, which can cause local buckling or flutter.…”

Section: Structural Modelmentioning

confidence: 99%

“…These challenges require innovative solutions: new high-temperature materials, a thermal protection system (TPS), and possibly coated leading edges with active cooling. The maximum operating temperature of titanium-based alloys varies between 800 and 1300 K [36,37]. Such materials were studied for potential application in the National Aerospace Plane (NASP) program.…”

Section: Structural Modelmentioning

confidence: 99%

Uncertainty Propagation in Integrated Airframe–Propulsion System Analysis for Hypersonic Vehicles

Lamorte

Friedmann

Dalle

et al. 2015

Journal of Propulsion and Power

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Air-breathing hypersonic vehicles are based on an airframe-integrated scramjet engine. The elongated forebody that serves as the inlet of the engine is subject to harsh aerothermodynamic loading, which causes it to deform. Unpredicted deformations may produce unstart, combustor chocking, or structural failure due to increased loads. An uncertainty quantification framework is used to propagate the effects of aerothermoelastic deformations on the performance of the scramjet engine. A loosely coupled airframe-integrated scramjet engine is considered. The aerothermoelastic deformations calculated for an assumed trajectory and angle of attack are transferred to a scramjet engine analysis. Uncertainty associated with deformation prediction is propagated through the engine performance analysis. The effects of aerodynamic heating and aerothermoelastic deformations at the cowl of the inlet are the most significant. The cowl deformation is the main contributor to the sensitivity of the propulsion system performance to aerothermoelastic effects.across thickness of skin h 1 , h 2 = thickness of thermal protection system layers h 3 = thickness of structural layer k = thermal conductivity M = Mach number m f = expected value of f _ m air = air mass flow rate _ m f = fuel mass flow rate P = pressure q aero = aerodynamic heat flux q ∞ = dynamic pressure Re = Reynolds number based on length of 1 m T = temperature T r = recovery temperature t = flight time u = axial displacement v = lateral displacement w = transverse displacement w j = weight in numerical integration x 0 ; y 0 ; z 0 = coordinate system for corrugated panel x = coordinate along vehicle, from leading edge, positive aft y = coordinate in spanwise direction, from centerline of vehicle z = coordinate normal to vehicle, from leading edge point, positive up α = angle of attack α T = thermal expansion coefficient α f = angle of attack of trajectory γ = specific heat ratio, c p ∕c v ξ 1 , ξ 2 = uncertain variables ν = Poisson ratio ϵ = emissivity ρ = density of air ρ M = density of material σ f = standard deviation of f ϕ j = interpolation function Subscripts i = initial value st = stoichiometric condition wall = at wall 0 = total condition 4 = condition at exit of combustor ∞ = freestream condition

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“…A survey of the literature reveals a wide range of design strategies for mitigating the high temperatures experienced in hypersonic flight. [21][22][23][24] This study considers a thermal protection system consisting of an outer heat shield and middle insulation layer on top of the skin as shown in Fig. 7.…”

Section: Iiib Control Surface Modelmentioning

confidence: 99%

“…(21). Once d (n+1) is obtained, the total motion of the unconstrained degrees of freedom in physical space is computed via Eqs.…”

mentioning

confidence: 99%

Effect of Control Surface-Fuselage Inertial Coupling on Hypersonic Vehicle Flight Dynamics

Falkiewicz

Frendreis

Cesnik

2011

AIAA Atmospheric Flight Mechanics Conference

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A simulation framework is developed for assessing the effect of control surface inertial loads on hypersonic vehicle response. The framework is based on a partitioned, timemarching approach in which the fuselage and control surface equations of motion are integrated independently and forces/motion at the interface are exchanged between the two systems at pre-determined time intervals. This approach is advantageous in that it does not require direct coupling of the fuselage and control surface models, and therefore allows for the models to be of dissimilar form. Equations of motion for both the fuselage and control surface are presented and a formulation for coupling the two systems is outlined which includes iterations within each aeroelastic time step. The methodology is applied to a representative hypersonic vehicle elevator control surface model which includes aerothermoelastic effects and is attached to a single degree of freedom oscillator representing the fuselage. Results show that control surface inertial effects lead to a departure of the instantaneous control surface lift force by up to a factor of eight with respect to the static value. Investigation of the system response under a commanded change in control surface deflection angle shows that control surface inertia results in departure of the instantaneous control surface pitching moment by up to a factor of 500 with respect to the static value. Nomenclature B= body-fixed reference frame c = generalized damping matrix c p = specific heat d = control surface elastic modal coordinates E = modulus of elasticity, Earth-fixed reference frame F = physical load vector f = generalized load vector f i = fuselage ordinary natural frequencies g = gravitational acceleration H(t) = Heaviside step function H i = coefficient matrices in control surface integration scheme h = altitude h i = thickness of i-th layer of thermal protection system I i = coefficient matrices in fuselage integration scheme

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Thermostructural concepts for hypervelocity vehicles

Cited by 19 publications

References 4 publications

Reduced-Order Aerothermoelastic Framework for Hypersonic Vehicle Control Simulation

Reduced-Order Aerothermoelastic Framework for Hypersonic Vehicle Control Simulation

Uncertainty Propagation in Integrated Airframe–Propulsion System Analysis for Hypersonic Vehicles

Effect of Control Surface-Fuselage Inertial Coupling on Hypersonic Vehicle Flight Dynamics

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