Characterizing In-Flight Temperature of Shaped Charge Penetrators in CTH

Sable, Peter; Helminiak, Nathaniel; Gullerud, Arne S.; Harstad, E. N.; Hollenshead, Jeromy T.; Hertel, Eugene S.

doi:10.1016/j.proeng.2017.09.782

Cited by 3 publications

(4 citation statements)

References 9 publications

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“…When the stress pulse reaches the bar and specimen interface, part of it ( R ) is reflected, and part of it ( T ) is transmitted to the transmission bar. According to the basic assumption of the Hopkinson dynamic compression test, the two-wave approach [48] can be used to obtain the expressions of stress, strain, and strain rate, as in Formulas (1)- (3), where A 0 is the cross-sectional area of the specimen, l 0 is the original length of the specimen, T is the strain of the transmitted wave propagating in the rod, R is the strain of the reflected wave propagating in the rod, A s and E 0 are the cross-sectional area and elastic modulus of the rod, C 0 is the sound velocity of the rod material, and t is the pulse width of the reflected wave.…”

Section: Experimental Methodsmentioning

confidence: 99%

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Comparative Study of the Dynamic Deformation of Pure Molybdenum at High Strain Rates and High Temperatures

Chen

Wang

et al. 2021

Materials

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To study the dynamic plastic properties of high-purity molybdenum materials at high temperature and high strain rate, we designed tests to compare the mechanical behaviour of two high-purity molybdenum materials with different purities and two with different processing deformation conditions under dynamic impact compression in the temperature range of 297–1273 K. We analysed the molybdenum materials’ sensitivities to the strain-hardening effect, strain rate-strengthening effect, and temperature-softening effect as well as the comprehensive response to the combined effect of the strain rate and temperature, the adiabatic impact process, and the microstructure at high temperature and high strain rate. Furthermore, based on a modified Johnson–Cook constitutive model, we quantitatively analysed the flow stresses in these materials. The calculation results strongly agree with the test results. Our findings indicate that the high-purity molybdenum materials show consistent sensitivity to the combined effect of strain rate and temperature regarding the dynamic plastic properties. The materials with higher purity are less sensitive to the combined effect of the strain rate and temperature, and those with less processing deformation experience more pronounced strain-hardening effects. Under high strain rate at room temperature, these materials are highly susceptible to impact embrittlement and decreases in dynamic plastic properties due to intergranular fracture in the internal microstructure. However, increasing the impact environment temperature can significantly improve their plastic properties. The higher the temperature, the better the plastic properties and the higher the impact toughness.

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Section: Experimental Methodsmentioning

confidence: 99%

“…Shaped charge collapse liners to EFP, JPC, and JET penetrators with ultra-high detonation pressure [1][2][3][4][5][6]. In the weapon industry, the penetrators are applied to pierce armour equipment and destroy solid targets as concrete [7][8][9][10]; the penetrators are also valuable in piercing oil exploration wells for civil application.…”

Section: Introductionmentioning

confidence: 99%

Comparative Study of the Dynamic Deformation of Pure Molybdenum at High Strain Rates and High Temperatures

Chen

Wang

et al. 2021

Materials

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“…Where 𝒗 0 ∈ ℝ 3 is a regular transport field, 𝚽 ∈ ℝ 4 the vector of the conserved variables, 𝐹 𝐸 = (𝐹 𝐸 𝛼 ) 𝛼 3 the Eulerian flux vectors, 𝑆 = (𝑆 𝑙 ) 𝑙 4 the source term and 𝐿 𝑣0 the transport operator associated to 𝒗 0 (5)…”

Section: Ale Frameworkmentioning

confidence: 99%

“…Regarding numerical modeling, two aspects are crucial to reproduce the jet generation process and its fragmentation. As the phenomenon is mainly in the field of large deformations, historical simulations have favored Eulerian approaches [1][2][3][4]. However, facing a huge compromise between accuracy and computation times particularly regarding the jet fragmentation process, Lagrangian and ALE approaches were then evaluated [3,5,6].…”

Section: Introductionmentioning

confidence: 99%

Innovative meshless approach for shaped charges applications

Collé¹,

Limido²,

Unfer³

et al. 2022

J. Phys.: Conf. Ser.

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We focus here on modelling shaped charges. Combining large deformations, numerous interfaceproductions, and strong damage mechanisms, those events are particularly challenging from a numerical point of view. Eulerian finite element methods are classically used for such modeling.However, they induce very long computation times, accuracy losses (projection algorithms), anddifficulties with opening criteria related to jet fragmentation. Among the Lagrangian approaches, the meshless method called Smoothed Particle Hydrodynamics (SPH) appears as a relevant alternative to prevent such shortcomings. Based on a set of moving interpolation points, it disregards any connectivity between its elements which makes it naturally well suited to handle material failure. Nevertheless, SPH schemes suffer from well-known instabilities questioning their accuracy and activating nonphysical processes,such as numerical fragmentation. Many stabilizing tools are available in the literature however, they either raise conservation and consistency issues or drastically increase the computation times. We propose then to use an alternative scheme called γ-SPH-ALE. Based on the ALE framework, it achieves robust and consistent stabilization through an arbitrary description of motion. Thanks to CFL-like conditions obtained through a nonlinear stability analysis, the scheme stability is ensured. By preventing spurious oscillations in elastic waves and correcting the so-called tensile instability, both stability and accuracy are increased regarding classical approaches. Also, taking advantage of GPU computing, such results are achieved in reduced computation times contrary to classical CPUimplementations. Its implementation on a “Viper” shaped charge shows that the scheme handles the jet generation process as well as its resulting interaction with a target.

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Deformation and Acceleration of Zn and Cu Liners under Explosive Shock Loading

Sutipanya

Saito

Nakashita

et al. 2019

2019 15th Hypervelocity Impact Symposium

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Shaped charge jets (SCJs) are of interest in the field of ballistics because of their excellent penetration ability. The various characteristics of an SCJ, such as density, temperature and length of the jet, are important when estimating the expected penetration depth. Therefore, these characteristics have been widely researched [1-5]. Zernow studied the density deficit associated with an in-flight jet using densitometry [1]. This prior work determined that the 15-20% density deficit of a Cu jet (as reported by Jamet [2]) includes a temperature contribution of 3.5%, an experimental error of 5% and a so-called “vacancy avalanche” contribution of 6.5%. Uhlig and Hummer measured the conductivity and temperature of in-flight Cu SCJs by employing a novel magnetic diffusion technique and five color radiometry. The resulting conductivity values indicated that the tip of the SCJ had a bulk temperature on the order of 1200 K, which is in the vicinity of the melting point of Cu (1350 K) [3]. Hertel et al. developed an analytical model for the SCJ formation process. CTH calculations utilizing their analytical model accurately predicted the thermodynamic characteristics of the SCJ [4, 5]. Huang quantified the density of an SCJ and reported the density distribution based on evaluating the x-ray absorption coefficient of a metal jet [6], and found that the density of a powder metal jet decreases toward the jet tip as the jet elongates. These prior reports indicate that observations of various jet features under high temperature conditions (close to the melting point) can be a useful means of assessing the density deficit of an SCJ.

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Characterizing In-Flight Temperature of Shaped Charge Penetrators in CTH

Cited by 3 publications

References 9 publications

Comparative Study of the Dynamic Deformation of Pure Molybdenum at High Strain Rates and High Temperatures

Comparative Study of the Dynamic Deformation of Pure Molybdenum at High Strain Rates and High Temperatures

Innovative meshless approach for shaped charges applications

Deformation and Acceleration of Zn and Cu Liners under Explosive Shock Loading

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