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Force chains based mesoscale simulation on the dynamic response of Al-PTFE granular composites

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Defence Technology（防务技术） 2021年第1期17卷 56-63页

作者： Le Tang Chao Ge Huan-guo Guo qing-bo yu Hai-fu Wang Beijing Institute of Technology China

Force chains based mesoscale simulation is conducted to investigate the response behavior of aluminumpolytetrafluoroethylene(Al-PTFE)granular composites under a low-velocity impact.A two-dimensional model followed the randomly normal distribution of real Al particles size is *** dynamic compressive process of Al-PTFE composites with varied Al mass fraction is simulated and validated against the *** results indicate that,force chains behavior governed by the number and the size of agglomerated Al particles,significantly affects the impact response of the *** failure mode of the material evolves from shear failure of matrix to debonding failure of particles with increasing density.A high crack area of the material is critical mechanism to arouse the initiation *** damage maintained by force chains during large plastic strain builds up more local stresses concentration to enhance a possible reaction *** addition,simulation is performed with identical mass fraction but various Al size distribution to explore the effects of size centralization and dispersion on the mechanical properties of *** is found that smaller sized Al particle of composites are more preferred than its bulky material in ultimate *** dispersed degree is facilitated to create stable force chains in samples with comparable particle *** simulation studies provide further insights into the plastic deformation,failure mechanism,and possible energy release capacity for Al-PTFE composites,which is helpful for further design and application of reactive materials.

关键词： Al-PTFE Granular composites Mesoscale simulation Dynamic response Force chains

Behind-plate overpressure effect of steel-encased reactive material projectile impacting thin aluminum plate

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Defence Technology（防务技术） 2022年第5期18卷 723-734页

作者： qing-bo yu Jia-hao Zhang Hong-wei Zhao Yan-wen Xiao Hai-fu Wang Beijing Institute of Technology State Key Laboratory of Explosion Science and TechnologyBeijing100081China Academy of the Rocket Force Beijing100094China Equipment Project Management Center Army Equipment DepartmentBeijing100072China

Ballistic impact and sealed chamber tests were performed on the steel-encased reactive material projectile(SERMP)to understand its behind-plate overpressure effect when impacting the thin aluminum *** reactive material encased with a 1.5 mm thick 30CrMnSiNi2A steel shell was launched onto the initially sealed test chamber with a 3 mm thick 2024-T3 thin aluminum cover ***,the overpressure signals in the test chamber were recorded by pressure *** experimental results indicate an unusual behind-plate overpressure effect:as the density of the projectile increases from 6.43 g/cm^(3) to 7.58 g/cm^(3) by increasing the content of tungsten powder,although its total chemical energy decreases,it produces a higher behind-target overpressure at a lower impact velocity.A theoretical model is proposed to predict the reaction length of reactive material inside the projectile based on one-dimensional shock wave theory to understand this unexpected *** addition,the deviation between the actual energy release and the theoretical calculation results,also the variation of overpressure rise time are analyzed and *** the analyses show,when the SERMP successfully penetrates the cover plate,an increasing density of the reactive material inside the projectile always means that the delaying rarefaction wave effect,an increase of its internal pressure and strain rate *** factors lead to the increase of the overpressure limit velocity and reaction extent of the reactive material,while the overpressure rise time decreases.

关键词： Reactive materials Steel-encased reactive material projectile Over-pressure effect Overpressure limit velocity Energy release

Chain damage effects of multi-spaced plates by reactive jet impact

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Defence Technology（防务技术） 2021年第2期17卷 393-404页

作者： yuan-feng Zheng Cheng-hai Su Huan-guo Guo qing-bo yu Hai-fu Wang State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China

Chain damage is a new phenomenon that occurs when a reactive jet impacts and penetrates multispaced *** reactive jet produces mechanical perforations on the spaced plates by its kinetic energy(KE),and then results in unusual chain rupturing effects and excessive structural damage on the spaced plates by its deflagration *** the present study,the chain damage behavior is initially demonstrated by *** reactive liners,composed of 26 wt%Al and 74 wt%PTFE,are fabricated through a pressing and sintering *** reactive liner thicknesses of 0.08 CD,0.10 CD and 0.12 CD(charge diameter)are chosen to carry out the chain damage *** results show a chain rupturing phenomenon caused by reactive *** constant reaction delay time and the different penetration velocities of reactive jets from liners with different thicknesses result in the variation of the deflagration position,which consequently determines the number of ruptured plates behind the ***,the finite-element code AUTODYN-3D has been used to simulate the kinetic energy only-induced rupturing effects on plates,based on the mechanism of behind armor debris(BAD).The significant discrepancies between simulations and experiments indicate that one enhanced damage mechanism,the behind armor blast(BAB),has acted on the ruptured ***,a theoretical model is used to consider the BAB-induced enhancement,and the analysis shows that the rupturing area on aluminum plates depends strongly upon the KE only-induced pre-perforations,the mass of reactive materials,and the thickness of plates.

关键词： Reactive materials Reactive jet Chain damage Behind armor blast

Penetration and internal blast behavior of reactive liner enhanced shaped charge against concrete space

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Defence Technology（防务技术） 2022年第6期18卷 952-962页

作者： Hao Zhang yuan-feng Zheng qing-bo yu Chao Ge Cheng-hai Su Hai-fu Wang State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081PR China

Penetration and internal blast behavior of reactive liner enhanced shaped charge against concrete space were investigated through experiments and *** volume of the enclosed concrete space is about 15 m^(3).The reactive liner enhanced shaped charge utilizes reactive copper double-layered liner,which is composed of an inner copper liner and an outer reactive liner,while the reactive material liner is fabricated by PTFE/Al(Polytetrafluoroethylene/Aluminum)powders through cold-pressing and *** explosion experiments show that,compared with the shaped charge which utilizes copper liner,the penetration cavity diameter and spalling area of concrete by the novel shaped charge were enlarged to 2 times and 4 times,***,the following reactive material had blast effect and produced significant overpressure inside the concrete closed *** analysis indicates concrete strength and detonation pressure of reactive material both affect the penetration cavity *** the blast behavior of reactive material inside the concrete space,developing TNT equivalence model and simulated on AUTODYN-3 D for *** results reproduced propagation process of the shock wave in concrete space,and revealed multi-peaks phenomenon of overpressure-time ***,the empirical relationship between the peak overpressure and relative distance for the shock wave of reactive material was proposed.

关键词： Shaped charge Penetration Blast Concrete Numerical simulation

Reaction characteristic of PTFE/Al/Cu/Pb composites and application in shaped charge liner

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Defence Technology（防务技术） 2022年第9期18卷 1578-1588页

作者： Huan-Guo Guo yuan-feng Zheng Suo He qing-bo yu Chao Ge Hai-fu Wang Beijing Institute of Technology Institution China

In this paper, the reaction characteristic and its application in shaped charge warhead of a novel reactive material, which introduced copper(Cu) and plumbum(Pb) into traditional polytetrafluoroethylene/aluminum(PTFE/Al), are studied. The thermal analysis and chemical reaction behavior of the PTFE/Al/Cu/Pb mixture are investigated by Differential Scanning Calorimetry(DSC),Thermo-gravimetry(TG), and Xray Diffraction(XRD) techniques. Then, the shaped charge liners with PTFE/Al/Cu/Pb reactive materials are fabricated, and the X-ray experiments show that they could form reactive jets with excellent performance under the detonation effects of the shaped charge. Based on that, the penetration experiments of shaped charge with PTFE/Al/Cu/Pb reactive liner against steel plates are carried out, and the results demonstrate that the PTFE/Al/Cu/Pb reactive jets could produce a deeper penetration depth compared to the traditional PTFE/Al reactive jets. Meanwhile, the PTFE/Al/Cu/Pb reactive jets also show significant inner-blast effects, leading to dramatically cracking or fragmentation behavior of the penetrated steel plates. This new PTFE/Al/Cu/Pb reactive liner shaped charge presents enhanced penetration behavior for steel targets that incorporates the penetration capability of a high-density and ductility jet, and the chemical energy release of PTFE-matrix reactive materials.

关键词： Reactive materials Shaped charge Reactive liner Jet formation Penetration behavior

Reactive jet density distribution effect on its penetration behavior

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Defence Technology（防务技术） 2023年第6期24卷 190-202页

作者： Huan-guo Guo Cheng-hai Su Yi-qiang Cai Suo He qing-bo yu Haifu Wang State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China

In this paper,the penetration mechanism of reactive jet with non-uniform density distribution is *** simulations show that the density deficit occurs in the whole reactive jet,and the density increases from the jet tip to *** density of jet tip is approximately 1.5 g/cm3,which is lower than that of the reactive liner *** X-ray experiments show similar results with the *** density decreasing effect of jet tip has a significant influence on the penetration behavior when the reactive jet impacts steel *** to the simulation results,this paper assumes that the density gradient in the jet section has linear ***,the deflagration pressure generated by each jet element at the bottom of crater is introduced into the Bernoulli *** on the virtual origin model and Szendrei-Held equation,the analytical models for penetration depth and radial cratering of reactive jet with the density reduction are ***,to further prove the validity of analytical models,the penetration experiments of the reactive liner shaped charge against steel plate under different standoffs are carried *** is a convergence between the analytical crater profiles and experimental results when reactive jets penetrate steel plates under different standoffs,especially at standoff of 1.5 and 2.0charge diameters.

关键词： Shaped charge Reactive jet Density distribution Jet penetration Virtual origin

The effect of sintering and cooling process on geometry distortion and mechanical properties transition of PTFE/Al reactive materials

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Defence Technology（防务技术） 2020年第3期16卷 720-730页

作者： Hai-fu Wang Bao-qun Geng Huan-guo Guo yuan-feng Zheng qing-bo yu Chao Ge State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China

In this research,the effect of the sintering and cooling process on geometry distortion and mechanical properties of PTFE/Al reactive material is *** particularly selected sintering temperatures,three different cooling modes(annealing cooling,normalizing cooling and rapid cooling),three different initial cooling temperature s,as well as six different final cooling temperatures were designed to compare the effects of sintering temperature,cooling rate,initial cooling temperature and final cooling temperature on the properties of reactive *** distortion was quantitatively analyzed by a statistic on the dimensional changes of the specimens and microscopic morphology.A mechanical response properties transition from brittle to ductile was found and *** combining the thermodynamic properties of PTFE and unsteady heat conduction theory,mechanisms of cooling induced morphology change,temperature induced distortion and strength decrease were *** results showed that the cooling rate has the most significant effect on the morphology transformation,while initial cooling temperature has more significant effect on the dimensional distortion than final cooling *** to the mechanical properties transition from brittle to plastic,a more prominent effect of initial cooling temperature than cooling rate and final temperature was revealed.

关键词： Reactive material Sintering Cooling Geometry distortion Mechanical properties

Effect of wave shaper on reactive materials jet formation and its penetration performance

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Defence Technology（防务技术） 2019年第4期15卷 495-505页

作者： Huan-guo Guo yuan-feng Zheng Le Tang qing-bo yu Chao Ge Hai-fu Wang Beijing Institute of Technology

Wave shaper effect on formation behavior and penetration performance of reactive liner shaped charge(RLSC)are investigated by experiments and *** reactive materials liner with a density of2.3 g/cm^3 is fabricated by cold pressing at a pressure of 300 MPa and sintering at a temperature of 380℃.Experiments of the RLSC with and without wave shaper against steel plates are carried out at standoffs of0.5,1.0,and 1.5 CD(charge diameter),*** experimental results show that the penetration depths and structural damage effects of steel plates decrease with increasing the standoff,while the penetration depths and the damage effects of RLSC without wave shaper are much greater than that with wave shaper at the same *** understand the unusual experimental results,numerical simulations based on AUTODYN-2 D code are conducted to discuss the wave shaper effect,including the propagation behavior of detonation wave,the velocity and temperature distribution of reactive jet,and penetration depth of reactive *** simulations indicate that,compared with RLSC without wave shaper,there is a higher temperature produced inside reactive jet with wave *** unusual temperature rise effects are likely to be an important mechanism to cause the initiation delay time of reactive jet to decline,which results in significantly decreasing its penetration performance.

关键词： Shaped charge Reactive materials liner Wave shaper Reactive jet Penetration performance

Shock-induced reaction behaviors of functionally graded reactive material

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Defence Technology（防务技术） 2021年第5期17卷 1687-1698页

作者： Ying yuan Zhen-yang Liu Suo He Chao Ge qing-bo yu yuan-feng Zheng Hai-fu Wang Beijing Institute of Technology State Key Laboratory of Explosion Science and TechnologyBeijing100081China

In this paper,the ballistic impact experiments,including impact test chamber and impact double-spaced plates,were conducted to study the reaction behaviors of a novel functionally graded reactive material(FGRM),which was composed of polytetrafluoroethylene/aluminum(PTFE/Al)and PTFE/Al/bismuth trioxide(Bi_(2)O_(3)).The experiments showed that the impact direction of the FGRM had a significant effect on the *** the same impact velocity,when the first impact material was PTFE/Al/Bi_(2)O_(3),compared with first impact material PTFE/Al,the FGRM induced higher overpressure in the test chamber and larger damaged area of double-spaced *** theoretical model,which considered the shock wave generation and propagation,the effect of the shock wave on reaction efficiency,and penetration behaviors,was developed to analyze the reaction behaviors of the *** model predicted first impact material of the FGRM with a higher shock impedance was conducive to the reaction of reactive *** conclusion of this study provides significant information about the design and application of reactive materials.

关键词： Functionally graded reactive material PTFE/Al Reaction behavior Ballistic impact experiments Reaction efficiency