Accession Number : AD0663154

Title :   EXPERIMENTAL AND THEORETICAL INVESTIGATION OF TEMPERATURES AND STRESSES IN ABLATING THICK-WALLED HEMISPHERES.

Descriptive Note : Research rept.,

Corporate Author : POLYTECHNIC INST OF BROOKLYN N Y DEPT OF AEROSPACE ENGINEERING AND APPLIED MECHANICS

Personal Author(s) : Parisse,Richard F. ; Nardo,S. V.

Report Date : NOV 1967

Pagination or Media Count : 97

Abstract : Hypersonic wind tunnel tests of 7 3/4 inch diameter Plexiglas and Nylon hemispheres were designed and conducted at the Preston R. Bassett Laboratory of the Polytechnic Institute of Brooklyn. A shrouded model technique was utilized to simulate Mach 15 to 20 flight. The models were instrumented with thermocouples and strain gages from which continuous time histories of temperature and strain were recorded. In addition, ablation measurements were made after the models were tested. The experimental results were compared with theoretical calculations of strain, temperature and ablation. A point-symmetric ablation and temperature analysis was conducted using a heat balance technique. The assumed temperature profiles were used in a point-symmetric thermal stress analysis in which a variation of the modulus of elasticity with temperature was approximated by using a concentric layer technique. The relative accuracy of this latter technique was determined by comparison with a perturbation solution for continuously varying modulus of elasticity. The effect of axisymmetric pressure distributions, as well as the boundary condition imposed by the model support, was considered in an axisymmetric layer analysis. A comparison between theory and experiment indicates good qualitative results and good to poor quantitative results. The details of the analyses, and the comparison between the theoretical predictions and experiment are discussed. (Author)

Descriptors :   (*ABLATION, *THERMOPLASTIC RESINS), THERMAL STRESSES, HEMISPHERICAL SHELLS, TEMPERATURE, ACRYLIC RESINS, NYLON, HYPERSONIC FLOW, WIND TUNNEL MODELS, MODEL TESTS, HEAT TRANSFER, STRAIN(MECHANICS)

Subject Categories : Plastics
      Air Condition, Heating, Lighting & Ventilating
      Thermodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE