Studies On The Impact Response Of Hypersonic Flow Over A Blunt Wedge And Structure

The design of hypersonic vehicle is a complex problem based on hypersonic aerodynamics and involving multidisciplinary and multi-domain.Problems of hypersonic aerodynamics and aerodynamic heating,structures and materials technology are the main technological difficulties.Under such technology background,considering,on one hand,there may be pulse disturbance in the flight environment of hypersonic vehicle,such as explosive shock wave,non-uniform of incoming flow and so on,and all this will significantly affect the flow characteristic and structural mechanical properties of the vehicle;on the other hand,the hypersonic vehicle may also suffer impacting from solid object especially during the flight,for example,in the take-off stage of space shuttle Columbia,the impact of the foam insulation on the leading edge of the wing caused the failure of the carbon-carbon panel;for another example,when intercepted by air-defense missiles,the vehicle will not only suffer the shock wave but also the impact of shrapnel;in addition,the flight track of the supersonic vehicle means that encounter with space debris is possible.To sum up,whether the disturbance of shock wave or the impacts of solid object are subsistent threatens to hypersonic vehicles.Especially,when the skin of the vehicle aerodynamic heated,the influence of the impact on the flow field and the structure are more significant and complex.In view of this,this paper studies the response of hypersonic flow filed and the structure to the influence of the impact of shock wave and solid object.Basically has the following several aspects:(1)The method which adopts high order accuracy finite difference scheme direct solution of complete Navier-Stokes equation to simulate unsteady flow was introduced.That is,using S-W flux vector splitting method to split the inviscid terms of the Navier-Stokes equation into positive flux terms and negative flux terms,and the two terms was discretized using five order upwind WENO scheme.Using six order central difference scheme to discrete viscosity term.The third order explicit TVD Runge-Kutta scheme was used for time advancement solution.The reliability of the constructed direct numerical simulation(DNS)method was verified.Simultaneously,the analytical method that based on Abaqus user subroutine to solve the structural thermal mechanical coupling problem under impact load was introduced,including Johnson-Cook model and three-dimensional composite progressive damage simulation method and so on.(2)Based on theconstructed high order DNS method solving Navier-Stokes equation,the response of hypersonic flow filed to freestream pulse wave and the stability characteristic of the boundary layer were researched;the mutual interference between frestream pulse wave and shock wave as well as boundary layer,and the generation and evolution characteristics of the wave disturbance in the hypersonic boundary layer were analyzed.Simultaneously,the effect of wall temperature,disturbance frequency and the type of the pulse wave were studied;the response characteristic of the hypersonic flow filed and boundary layer under different wall temperature,different disturbance frequency and different types of pulse wave were analyzed,the effect of all the conditions to the generation and evolution characteristics of the disturbance waves in the hypersonic boundary layer were obtained.(3)Based on the result of the DNS of the hypersonic unsteady flow over a blunt wedge under pulse wave,individual analyzed the effect of a mixture of freestream pulse wave and slow acoustic wave on the aerothermodynamics parameters of the blunt wedge surface including pressure,friction coefficient of wall,temperature,density and heat flux and so on.The response regularity of wall parameters to freestream pulse wave was given,the effect of the disturbance of freestream parameters to the local flow parameters of blunt wedge.Based on the wall pressure result obtained from DNS,the finite element software ABAQUS was instroduced to simulate the transient mechanical response of the structure under freestream pulse wave,the change rule of stress,strain and displacement of the structure under the impact of freestream pulse wave were given,the effect of wall pressure load changes to the structural response was investigated.(4)Based on Abaquse/Explicit,user subroutine VUMAT and Johnson-Cook model were used to simulate the high velocity impact response of Carbon Fiber Metal Laminates(FMLs)under different temperature load.The impact dynamic response and progressive damage of the FMLs was analyzed,focused on the effect of temperature load on their impact property.The failure models of the FMLs under different temperature were compared,and the effect of temperature load to the failure model of FMLs was discussed.Simultaneously,based on transient heat transfer and thermal mechanical coupling theory,the transient heat transfer of corrugated sandwich thermal protection system was analyzed,the thermal mechanical coupling mechanism of the corrugated sandwich thermal protection system was researched,the factors that can influence the thermal protective performance and thermodynamic response of the thermal protection system were discussed.The impact responses of thermal protection system panel under different aerodynamic heating conditions were simulated,the effect of thermal load to the impct resistance properties of thermal protection system panel was analyzed,and the impact response characteristics of the thermal protection system panel under different thermal environment was given.