Fracture model for cemented aggregates

Abstract

A mechanisms-based fracture model applicable to a broad class of cemented aggregates and, among them, plastic-bonded explosive (PBX) composites, is presented. The model is calibrated for PBX 9502 using the available experimental data under uniaxial compression and tension gathered at various strain rates and temperatures. We show that the model correctly captures inelastic stress-strain responses prior to the load peak and it predicts the post-critical macro-fracture processes, which result from the growth and coalescence of micro-cracks. In our approach, the fracture zone is embedded into elastic matrix and effectively weakens the material's strength along the plane of the dominant fracture

Quasistatic mechanical behavior of HMX- and TATB-based plastic-bonded explosives

“…The DMA test performed by Thompson et al (2012) shows that the viscosity of the PBX-9502 increases significantly from +25°C. For this material, temperature tends to make it more ductile while the strain rate 10 -3 and 10 -5 s -1 has very little influence on its behavior at -52°C (Zubelewicz et al, 2013). Asymmetry of the behavior between tension and compression is also observed.…”

“…Let us note that the ratchet growth phenomenon (cycles of temperature without mechanical loading yields irreversible strain) has never been observed for this material. For other TATB-based PBXs, the experimental database mainly includes monotonic uniaxial compression tests performed between 10 -5 s -1 and 10 -3 s -1 for temperatures from -52°C to 74°C (Blumenthal et al, 1999;Skidmore et al, 1998;Thompson et al, 2010;Zubelewicz et al, 2013), with creep phase (Gagliardi and Cunningham, 2007) or with load-unload cycles (Browning et al, 1984). There are also data on the tension behavior, in monotonic loading from 10 -5 s -1 to 10 -3 s -1 for temperatures from -52°C to 74°C (Thompson, 2002;Thompson et al, 2010;Zubelewicz et al, 2013) and two papers provide tension failure data for different temperatures and strain rates (Idar et al, 2000;Thompson et al, 2012a).…”

“…A review of the various tests carried out on these materials is proposed in section 2 of this paper. Published experimental data on PBXs are essentially limited to uniaxial compression or tension tests, at various temperatures, in which only longitudinal strains are measured (Blumenthal et al, 1999;Browning et al, 1984;Buechler, 2012aBuechler, , 2012bBuechler et al, 2013;Ellis et al, 2005;Funk et al, 1996;Gagliardi and Cunningham, 2007;Gray et al, 1998;Skidmore et al, 1998;Thompson, 2002;Thompson et al, 2010;Zubelewicz et al, 2013). Some compression tests on an HMX-based PBX under various confinement pressures can be mentioned (Wiegand et al, 2011) as well as a torsion test on PBX-9501 (Gagliardi and Cunningham, 2009).…”

Numerical Simulation of Crack Initiation and Growth in PBX High Explosive Subject to Compression

“…Polymer-bonded explosives (PBXs), highly particle filled composite materials comprised of 90-95% by weight of powerful explosive crystals held together by a polymeric binder (5-10% by weight), have been used in a wide variety of applications ranging from rocket propellants to the main explosive charge in conventional munitions for civil and defence fields [1][2][3][4]. In recent decades, the safety and reliability of structures under low-speed impact have been highly valued by governments and engineering fields, and so the failure of PBX explosives has attached great attention by academic circles [5][6][7][8][9][10][11][12].…”

A mechanisms-based model for dynamic behavior and fracture of geomaterials

“…The proposed approach utilizes results obtained in [12,13], where the tensor representation theory is shown to be a very useful tool in the hands of a modeler [14]. First, we determine the dominant deformation and fracture mechanisms in a geomaterial.…”