Parallel Plate Plastometry of Plastic Propellant. Part 2. Determination of Plastoviscosity and the Flow Curve Equation
Abstract
The use of the parallel-plate plastometer has been extended to measure the plastoviscosity of a representative plastic propellant over a wide strain-rate range (about 10(exp -5) to 10 s -1). The experimental technique is to compress a cylindrical specimen but the results can be analyzed in two ways, yielding either zero-strain or finite-strain plasto- viscosities respectively. Both plastoviscosities are, within experimental scatter, inversely proportional to the square root of the strain-rate, and range from about 100 to 0.1 MN s/m squared (1 GP to 1 MP). The plastoviscosity decreases rapidly and exponentially with increasing strain. When the finite-strain measurements are extrapolated to zero strain, there is good agreement with the zero-strain measurements. The flow curve for a given strain, relating strain-rate with stress, is parabolic. The yield stress and shear-hardening coefficient (measured separately) have been taken into account, resulting in a complete flow equation linking stress, strain and strain-rate, corresponding to a family of flow curves.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1972
- Accession Number
- ADA473686
Entities
People
- Virginia M. Gledhill
- W. A. Dukes