Time-temperature superposition applied to PBX mechanical properties

Abstract

Low strain rate compression measurements of PBXN-9, PBX 9501, and mock 9501 AIP Conference Proceedings 429, 587 (1998) Abstract. The use of plastic-bonded explosives (PBXs) in weapon applications requires that they possess and maintain a level of structural/mechanical integrity. Uniaxial tension and compression experiments are typically used to characterize the mechanical response of materials over a wide range of temperatures and strain rates, providing the basis for predictive modeling in more complex geometries. After many years of data collection on a variety of PBX formulations, we have here applied the principles of time-temperature superposition to a mechanical properties database which includes PBX 9501, PBX 9502, and HPP (propellant). Consistencies are demonstrated between the results of quasi-static tension and compression, dynamic Split-Hopkinson Pressure Bar (SHPB) compression, and cantilever Dynamic Mechanical Analysis (DMA). Timetemperature relationships of maximum stress and corresponding strain values are analyzed, in addition to the more conventional analysis of modulus. The extensive analysis shows adherence to the principles of time-temperature superposition and correlations of mechanical response to binder glasstransition temperature (T g ) and specimen density. Direct ties exist between the time-temperature analysis and the underlying basis of a useful existing PBX mechanical model (ViscoSCRAM). Results give confidence that, with some limitations, mechanical response can be predicted at conditions not explicitly measured.

High strain rate characterization of polymers

“…The first use of this technique to interpret rate dependence of yielding behavior was probably by Rinde, Bauwens and Bouwens-Crowet [124][125][126]: a master curve of rate dependence extending outside the range of experimentally accessible rates was calculated. More recently this approach has been applied to a number of materials: PC and PVDF [5], PTFE [127], PE [128], Polymer bonded explosives [4,129] and PVC [17] (see also a recent discussion of different shifting methods [130]). It should be noted that for rubbery materials with a glass transition close to room temperature, the effect of this transition would be expected to be seen, and is seen, in the rate dependence.…”

Experimentally simulating high-rate behaviour: rate and temperature effects in polycarbonate and PMMA

“…As expected, in materials which have no lower order transition, or if the transitions occur at sufficiently low temperatures, a linear dependence on log(ε) is observed [14]. Time-temperature superposition has been applied in this context to polymers [15,16], composites [17,18] and polymer-based foams [19]. Furthermore, authors have successfully applied two process models to describe rate and temperature dependence, and this forms the basis of recent constitutive model development [12,15,16,[20][21][22][23][24][25].…”

Experimentally Simulating High Rate Composite Deformation in Tension and Compression: Polymer Bonded Explosive Simulant

“…Over the past 15 years, a wide range of investigations of the mechanical properties of polymer bonded explosives (PBXs), and their simulants (PBSs), under high rate deformation have been seen in literature [3,[16][17][18][19][20][21][22][23][24][25], often using Brazilian testing to study tensile behavior (e.g. [26,27]).…”