A Method for the Determination of the Viscoelastic Relaxation Modules of PBX by Confined SHPB Measurements

Heider, N.; Steinbrenner, A.; Aurich, H.

doi:10.1007/s40870-017-0100-z

Cited by 5 publications

(2 citation statements)

References 19 publications

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“…The Visco-SCRAM model developed by Bennett et al [12] has been widely applied to study the mechanical response of PBXs under dynamic loads [20,21]. PBXs are highly filled particulate composite materials that show macroviscoelastic behavior [22,23] and heterogeneous microcrack evolution [24,25]. This model combines a multi-Maxwell viscoelasticity material model with a statistical crack mechanics model to well simulate material behaviors.…”

Section: Constitutive Materials Modelmentioning

confidence: 99%

Effect of Continuous Damage Accumulation on Ignition of HMX‐Based Polymer Bonded Explosives under Low‐Velocity Impact

Liu

Chen

Zhang

2020

Propellants Explo Pyrotec

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The ignition phenomena of polymer-bonded explosives (PBXs) due to hotspot formation from grit/friction, shear band formation, and friction between microcrack surfaces have not yet been clarified. Microcracks are known to play a critical role in PBX ignition under low-velocity impacts. Further, microcrack evolution determines whether or not a specimen ignites because of complex mechanicalthermal-chemical coupled processes. Although many studies have investigated the multiphysics processes of ignition under single impacts, few have investigated multiple-impact scenarios that are more likely in reality. The present study focuses on the influence of continuous damage accumulation during multiple impacts on the safety assessment of octahydro-1,3,5,7-Tetranitro-Tetrazocine (HMX)-based PBXs. The Visco-SCRAM model combined with restart technology is applied to conduct simulations with the standard confined Steven test. By controlling the first impact velocity, the damage accumulation could be designed. When the first impact velocity increases from 5 to 20 m/s, the second impact velocity threshold decreases from 34 to 22 m/s and specific mechanical energy decreases from 600 to 240 m 2 /s 2. Multiple impacts change the temperature distribution and ignition position. Further, different projectile shapes influence multiple impacts differently. Owing to continuous damage accumulation, the second impact velocity threshold decreases for flat and pin projectiles. Dimensionless analysis reveals that the trends of critical dimensionless parameters for flat and pin projectiles are similar, whereas oval projectiles show a different response.

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Section: Constitutive Materials Modelmentioning

confidence: 99%

Effect of Continuous Damage Accumulation on Ignition of HMX‐Based Polymer Bonded Explosives under Low‐Velocity Impact

Liu

Chen

Zhang

2020

Propellants Explo Pyrotec

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“…The visco-SCRAM was first proposed by Bennett et al [7] and has been widely applied to analyze the mechanical response of PBXs under different strain rates . The model considers that PBXs are subjected to viscoelastic mechanical effects under dynamic loadings [27][28], which can be described based on the Maxwell viscoelasticity model. Moreover, the microcrack evolution is combined with the Maxwell viscoelasticity model to give a complete description of the mechanical behavior of PBXs [29].…”

Section: Constitutive Materials Modelmentioning

confidence: 99%

Non‐Shock Ignition Probability of Octahydro‐1,3,5,7‐Tetranitro‐Tetrazocine‐Based Polymer Bonded Explosives Based on Microcrack Stochastic Distribution

Chen

Zhang

et al. 2019

Propellants Explo Pyrotec

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We investigate stochastic microcracks of a heterogeneous microstructure as the primary mechanism determining the non‐shock ignition probability of octahydro‐1,3,5,7‐tetranitro‐1,2,3,5‐tetrazocine‐based polymer‐bonded explosives. To quantify the ignition probability, we modify the viscoelastic cracking constitutive model by considering randomly distributed microcracks and combine this model with the hot‐spot model and the Monte Carlo method. This method is validated by using a standard Steven test simulation, and we quantify how the microcrack stochasticity affects the ignition probability. The high‐temperature region clearly changes compared with the case of single microcrack size. The discrepancy in the mechanical response of each element due to the heterogeneous microcracks causes a shear deformation, which increases the temperature. The difference between a uniform distribution and a normal distribution in microcrack size is also discussed. For a given impact velocity, the ignition probability for the normal microcrack size distribution exceeds that for the uniform microcrack size distribution. Although the two distributions have the same mean and variance, the real range in microcrack size corresponding to the normal distribution exceeds that for the uniform distribution. The results show that the sample radius does not significantly affect the ignition probability, whereas the opposite is true for the sample thickness. The ignition‐probability curve is obtained in these cases. For sample dimensions of φ70 mm×13 mm, φ98 mm×13 mm, φ140 mm×13 mm, and φ98 mm×26 mm, the impact velocity thresholds corresponding to ignition probabilities in the range 0 %–99 % are 41.0–43.7, 41.0–44.3, 40.0–44.6, and 62.0–67.2 m/s, respectively, which is consistent with experimental results.

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Macro‐Micromechanics‐Based Ignition Behavior of Explosives Under Low‐Velocity Impact

Chen

et al. 2023

Nano and Micro‐Scale Energetic Materials

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A Method for the Determination of the Viscoelastic Relaxation Modules of PBX by Confined SHPB Measurements

Cited by 5 publications

References 19 publications

Effect of Continuous Damage Accumulation on Ignition of HMX‐Based Polymer Bonded Explosives under Low‐Velocity Impact

Effect of Continuous Damage Accumulation on Ignition of HMX‐Based Polymer Bonded Explosives under Low‐Velocity Impact

Non‐Shock Ignition Probability of Octahydro‐1,3,5,7‐Tetranitro‐Tetrazocine‐Based Polymer Bonded Explosives Based on Microcrack Stochastic Distribution

Macro‐Micromechanics‐Based Ignition Behavior of Explosives Under Low‐Velocity Impact

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