@article{labarbera_zikry_2015, title={Heterogeneous thermo-mechanical behavior and hot spot formation in RDX-estane energetic aggregates}, volume={62}, ISSN={["1879-2146"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84928274530&partnerID=MN8TOARS}, DOI={10.1016/j.ijsolstr.2015.02.007}, abstractNote={Hot spot formation has been investigated in energetic aggregates with a viscoelastic binder and crystalline grains that has been subjected to dynamic thermo-mechanical loading conditions. A dislocation-density based crystalline plasticity, finite viscoelasticity, and specialized finite-element formulations were used to predict hot spot formation due to dynamic thermo-mechanical loading conditions in RDX–estane energetic aggregates. The interrelated effects of grain boundary (GB) misorientations, porosity, grain morphology, dislocation densities, polymer binder relaxation, and crystal–binder interactions were coupled with adiabatic plasticity heating, thermal decomposition, viscous dissipation heating, and thermal conduction to analyze aggregate behavior and hot spot formation. The predictions indicate that hot spot formation occurs when temperatures become unbounded in localized regions at the peripheries of RDX crystals where RDX–estane interfacial incompatibilities result in crystal sliding and localized plastic deformation at RDX crystal edges and interfaces.}, journal={INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES}, author={LaBarbera, D. A. and Zikry, M. A.}, year={2015}, month={Jun}, pages={91–103} }
 @article{labarbera_zikry_2015, title={Interfacial effects on fracture nucleation and propagation in crystalline-amorphous energetic material systems}, volume={104}, ISSN={["1879-0801"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84927732379&partnerID=MN8TOARS}, DOI={10.1016/j.commatsci.2015.03.038}, abstractNote={Local failure modes, such as the nucleation and propagation of a pre-existing crack, have been investigated for energetic materials with a viscoelastic binder and crystalline grains subjected to dynamic thermal and mechanical loading conditions. A crystalline plasticity with dislocation density, finite viscoelasticity, dynamic fracture nucleation and propagation methods, and finite element methods were used to study crack nucleation and propagation due to dynamic thermal and mechanical loading conditions. The interrelated effects of dislocation densities, grain boundary (GB) misorientations, polymer binder relaxation, and interactions between crystal and binder were coupled to material thermal decomposition, adiabatic inelastic heating, viscous dissipation heating, and thermal conduction to analyze interfacial fracture behavior in RDX–estane systems. The predictions indicate that cracks propagated toward the binder and were arrested due to the viscous nature of the polymer binder and plasticity buildup. For low angle misorientations, the pre-existing crack propagated toward the binder with increasing crack tip speed until it reaches the binder, at which point the crack was arrested. For high angle misorientations, the crack propagated toward the binder and was arrested, adjacent to the binder, due to plastic deformation and lattice rotations. A secondary crack eventually nucleated and propagated to the interface, where it was arrested.}, journal={COMPUTATIONAL MATERIALS SCIENCE}, author={LaBarbera, D. A. and Zikry, M. A.}, year={2015}, month={Jun}, pages={10–22} }
 @article{brown_labarbera_zikry_2014, title={Laser interaction effects of electromagnetic absorption and microstructural defects on hot-spot formation in RDX-PCTFE energetic aggregates}, volume={22}, ISSN={["1361-651X"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84903137725&partnerID=MN8TOARS}, DOI={10.1088/0965-0393/22/5/055013}, abstractNote={Hot-spot formation in energetic aggregates subjected to dynamic pressure loading and laser irradiation has been investigated. Specialized finite-element techniques with a dislocation-density-based crystalline plasticity constitutive formulation and thermo-mechanical coupling of heat conduction, adiabatic heating, laser heating and thermal decomposition were used to predict hot-spot formation in RDX–polymer aggregates subjected to dynamic pressures and laser energies. The effects of the electromagnetic absorption coefficient coupled with void distribution and spacing, grain morphology, crystal–binder interactions and dislocation densities were analyzed to determine their influence on the time, location and mechanisms of hot-spot formation. Four different mechanisms for hot-spot initiation under dynamic laser and pressure loads were identified, which depend on the localization of plastic shear strain and laser heat absorption within the aggregate. The predictions indicate that hot-spot formation is accelerated by higher absorption coefficients and by localized plastic deformations that occur in areas of significant laser heating.}, number={5}, journal={MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING}, author={Brown, Judith A. and LaBarbera, Darrell A. and Zikry, Mohammed A.}, year={2014}, month={Jul} }
 @article{pearson_labarbera_prabhugoud_peters_zikry_2013, title={Experimental and Computational Investigation of Low-Impact Velocity and Quasi-Static Failure of PMMA}, volume={53}, ISSN={["1741-2765"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84872276475&partnerID=MN8TOARS}, DOI={10.1007/s11340-012-9650-0}, number={1}, journal={EXPERIMENTAL MECHANICS}, author={Pearson, J. D. and LaBarbera, D. and Prabhugoud, M. and Peters, K. and Zikry, M. A.}, year={2013}, month={Jan}, pages={53–66} }
 @article{labarbera_zikry_2013, title={The effects of microstructural defects on hot spot formation in cyclotrimethylenetrinitramine-polychlorotrifluoroethylene energetic aggregates}, volume={113}, ISSN={["0021-8979"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84879877008&partnerID=MN8TOARS}, DOI={10.1063/1.4811684}, abstractNote={Shock initiation due to hot spot formation has been investigated in energetic aggregates subjected to dynamic thermo-mechanical loading conditions. A dislocation-density based crystalline plasticity and specialized finite-element formulations were used to predict hot spot formation due to dynamic thermo-mechanical loading conditions in cyclotrimethylenetrinitramine-polymer energetic aggregates. The effects of grain boundary misorientations, porosity, grain morphology, dislocation densities, and crystal-binder interactions were coupled with adiabatic plasticity heating, thermal decomposition, and dissipated heat to analyze hot spot formation. The predictions indicate that hot spot formation occurs when temperatures become unbounded in localized regions between voids. The time to hot spot formation decreases with increases in dynamic pressure loads, which is consistent with experimental results.}, number={24}, journal={JOURNAL OF APPLIED PHYSICS}, author={LaBarbera, D. A. and Zikry, M. A.}, year={2013}, month={Jun} }