Accession Number : ADA114345

Title :   An Analysis of Solid Propellant Transient Viscoelastic Response under Motor Ignition Conditions.

Descriptive Note : Final rept. 9 Jul 80-15 Apr 81,


Personal Author(s) : Thrasher,Durwood I ; Corbett,Eileen

PDF Url : ADA114345

Report Date : Jan 1982

Pagination or Media Count : 37

Abstract : Programmable calculator programs were written to calculate stress responses for stepwise and rampwise approximations to a given strain history. These programs were tailored to calculate the error relative to the exact-history result and also to investigate different techniques of applying stepwise approximations and different techniques for selecting stress output times within each step or ramp. The optimum rampwise approximation produced one-tenth the rms error in stress produced by the optimum stepwise approximation for the same number of time intervals. Using only 10 time intervals to approximate a fourth-order polynomial strain history, the rms error in stress with the rampwise approximation was only 0.5%. The rampwise approximation program was then rewritten for analysis of an arbitrary input strain history (up to 35 ramps). A dynamic pressurization-strain test reported in AFRPL-TR-78-68 was analyzed using the rampwise strain history approximation as well as a polynomial approximation. For both strain history approximations, the stress history calculated using relaxation data agreed well with the measured stress history up to the peak stress point.

Descriptors :   *Solid propellants, *Ignition, *Viscoelasticity, *Response, Approximation(Mathematics), Calculators, Strain(Mechanics), Stress analysis, Peak values, Stresses, Computer programming, Motors, Polynomials, Transients, Relaxation, History

Subject Categories : Acoustics
      Solid Rocket Propellants

Distribution Statement : APPROVED FOR PUBLIC RELEASE