Thermo-viscoplastic analysis of hypersonic structures subjected to severe aerodynamic heating

Abstract

A bst rnct A tliermo-viscoplaatic computational method for hypersonic structures is presented. The method employs a unified viscoplastic constitutive niotlel implemented i n a finite elcment approach lor quasi-static tlicrinal-strrictiiral analysis. Applications ol the approach to conveclively cooled hypersonic structures illiistrate the eflcctiveness of the approach and provide insight into the transient inelastic structural behavior at elevated teniperatures.

Hp-Meshless Cloud Method for Dynamic Fracture in Fluid Structure Interaction

“…For the materials considered in this project, the constitutive equations are defined by a linear relationship between the Cauchy stress and strain tensors. It can be shown, using standard arguments of Continuum Mechanics [22,49], that for large deflections / small strains problems this is equivalent to a linear relationship between the second Piola-Kirchhoff stress tensor and a Green-Lagrange strain tensor:…”

“…Flow-Structure Interaction (FSI) has been the topic of many research efforts, especially in application to hypersonics [49] and aeroelasticity [1,8,55]. Historically, most of the software development efforts in this area have been focused on selected applications and, accordingly, utilized some specific flow-structure coupling schemes (one-way, staggered one-way, two-way, etc.).…”

Experimental Study of Plate Buckling Induced by Spatial Temperature Gradients

“…Finite element analysis with unified constitutive models have been under development for about 15 years. Thornton et al [3] describe these efforts and present a thermoviscoplastic finite element computational method for hypersonic structures. Applications of the approach to convectively cooled hypersonic structures illustrate the approach and provide insight into the transient viscoplastic behavior at elevated temperatures.…”

“…To determine the critical buckling temperature, small transverse bending displacements of the plate are assumed. The stresses obtained from the solution of the uncoupled plane stress problem is used to define the in-plane stress resultants N x, Ny, N xy, which are obtained by multiplying the stresses by the plate thickness h. The displacement w(x, y) of the buckled plate is governed by the linear differential equation (3) where D is the flexural rigidity of the plate, D = Eh 3/12(1 -v 2 ) where v is Poisson's ratio. In [6] the critical buckling temperature was obtained for simple supports by the principle of minimum potential energy using a series of trigonometric functions for the transverse displacement.…”

“…3 The initial deformation of the test plate was measured with a coordinate measuring machine at NASA Langley Research Center. The initial transverse deflection of the plate is shown greatly exaggerated in Figure A.I.…”