Quasi–static studies of the deformation and failure of PBX 9501

Abstract

This paper examines the influence of microstructure on the quasi-static failure of PBX 9501, a polymer-bonded explosive (PBX) manufactured for the Los Alamos National Laboratory in America. Optical microscopy has been used to examine qualitatively cracked and pristine material. Consequent on the manufacturing process, the explosive crystals display angular features and natural facets. In addition, considerable growth twinning, internal defects and voidage has been observed. These defects are found significantly to alter the failure path. In common with other PBXs, failure paths tend to run around the long straight edges of the explosive filler and avoid regions of fine filler and binder. Explosive crystals were found to fracture due either to cracks propagating from another region or internal defects. These observations are confirmed by the use of high-resolution moiré interferometry. This sensitive optical technique allows the deformation of the sample to be measured up to and including the point of failure. By taking white-light micrographs that are in exact registration with the measured displacement maps, the influence of the underlying microstructure can be seen.

Microstructure, deformation and failure of polymer bonded explosives

“…The Brazilian test, or diametrical compression, in which a disc of material is loaded diametrically in compression, has been used to generate tensile stress and estimate the tensile failure stress of a material without the inconvenience of uniaxial dumbbell testing [8]. Application of this method to explosives has been undertaken by some researchers [3,5,6,[9][10][11]. The researchers at Cavendish Laboratory, Cambridge, UK have done extensive work in this field by introducing some sophisticated techniques [12][13][14][15].…”

“…Optical and electronic microscopic examinations are effective methods to study the microstructure and its evolution and to reveal the mesomechanical deformation and failure mechanisms of explosive materials. Different microscopic methods including scanning electron microscopy (SEM), environmental scanning electronic microscopy (ESEM) [5,6] and polarized light microscopy (PLM) [7] have been successfully used in this regard. The Brazilian test, or diametrical compression, in which a disc of material is loaded diametrically in compression, has been used to generate tensile stress and estimate the tensile failure stress of a material without the inconvenience of uniaxial dumbbell testing [8].…”

Macro-Micro Mechanical Behavior of a Highly-Particle-Filled Composite Using Digital Image Correlation Method

“…The quasi-static deformation fields were measured by this technique. The influence of particles microstructure was found to be significant for its fracture behavior 438 [6][7][10][11][12]. Rae et al [13] used DIC to investigate the effect of thermal aging on a UK PBX containing nitrocellulose.…”

“…The mechanical properties of PBX subjected to a range of conditions are important criteria to determine a safe working life. The study on the mechanical properties and the failure mechanisms of PBX has drawn much attention in recent years [1][2][3][4][5][6][7][8][9]. Low strengths and safety concerns bring additional difficulties in preparing samples and conducting mechanical tests of PBX.…”

Study on the State of Internal Stress and Strain of TATB-based Polymer Bonded Explosive Using Strain Markers and Cone-Beam Computed Tomography

“…Dai et al [13] investigated the micro-macro behaviour of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) granules by X-ray tomography and the discrete element model during the compacting process, and the results showed that the marginal region had the largest side pressure, finally forming a region with a large stress. Furthermore, real-time online monitoring technology has also been applied in some studies to investigate the mechanical properties of explosives and the distribution of the stress-strain field [19][20]. Zhou et al [21] conducted real-time microscopic examination to observe the process of deformation and failure of PBX material by a semi-circular bend test using a scanning electron microscope equipped with a loading stage.…”