Technique computes stresses resulting from axisymmetric transient thermal loading in circular solid-propellant grain section with circular ports. Propellant is assumed to be linear, thermal rheologically simple, viscoelastic material; material properties are represented by exponential series in time

Chen, J. C.

English

NASA Technical Reports Server

July 1973	 B73-10301 
NASA TECH BRIEF 
NASA Pasadena Office
	 C 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
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Structural Analysis of Viscoelastic Materials under

Thermal and Pressure Loading 
The designer of a solid-propellant rocket motor 
system must consider the structural problems that 
will arise because of thermal loading and pressure 
loading resulting from the burning of fuel and the 
stresses of the space environment. In order to predict 
the maximum imposed loading at which either exces-
sive deformation or fracture threshold is reached, es-
timates must be made of the stresses or strains in a 
viscoelastic propellant material caused by applied 
is loads. 
A technique has been developed for computing 
the stresses resulting from an axisymmetric transient 
thermal loading in a circular solid-propellant grain 
section with circular ports. The propellant is assumed 
to be a linear, thermal rheologically simple, viscoelas-
tic material; material properties are represented by 
an exponential series in time. In the expansion of the 
series, the relaxation time of each term is selected to 
provide the best fit of experimental data. The series 
expansion leads to a recurrence relation, which elfin-
mates the problem of recalculating the history of 
material response at each time step. Finally, the re-
currence matrix is used with a finite-difference general 
computer code to determine the effect of internal 
pressure on the stresses.. 
Note: 
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NASA Pasadena Office 
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Pasadena, California 91103 
Reference: TSP 78-10301 
Source: Jay C. Chen of 
Caltech/JPL
under contract to

NASA Pasadena Office 
(NPO-11727) 
Category 09 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
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Structural analysis of viscoelastic materials under thermal and pressure loading

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