The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
Xinke Xiao - One of the best experts on this subject based on the ideXlab platform.
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An investigation into horizontal water entry behaviors of Projectiles with different nose shapes
International Journal of Impact Engineering, 2012Co-Authors: Zitao Guo, Wei Zhang, Xinke Xiao, Gang Wei, Peng RenAbstract:Abstract In the present study, high-speed horizontal water entry behaviors of flat, ogival and hemispherical-nose Projectiles were studied experimentally and theoretically. Particular attention is given to characterizing the Projectile dynamics and the cavity evolution before a deep pinching starts. An analytical cavity model based on the solution to the Rayleigh–Besant problem was developed to describe the cavity dynamics of Projectile water entry. Three parameters in the cavity model were discussed and determined theoretically and experimentally. Numerical simulations using the AUTODYN-2D Lagrange–Euler coupling techniques were conducted to specially study the drag coefficients of Projectiles. Based on the experimental and numerical results, a drag coefficient model independent on the cavitation number was proposed. The results indicated that there are two variation laws for the three parameters in the cavity model; Additionally, the drag coefficients increase with the impact velocities with holding the Projectile nose constant and decrease with an increase in the Projectile nose coefficient (CRH) value. Good agreements were observed between analytical results and experimental observations.
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effect of Projectile hardness on deformation and fracture behavior in the taylor impact test
Materials & Design, 2010Co-Authors: Xinke Xiao, Wei Zhang, Zhongcheng MuAbstract:Abstract The ballistic perforation performance of a kinetic energy Projectile would be much more influenced by the Projectile’s deformation during the impact process. A Projectile may suffer from large deformation and even fracture as more and more advanced materials are used as resistant components. A comparison investigation was presented in this study concerning the deformation and fracture behavior of kinetic energy Projectiles manufactured from 38CrSi steel of two different hardness values. Flat-nosed Projectiles were fired in a two-stage compressed gun test facility against hard steel plates within the velocity range of 200–600 m/s. The impact process was monitored by a high-speed camera. Experimental results showed that, for the soft Projectiles there are three deformation and fracture modes, i.e., mushrooming, shear cracking and petalling, and that for the hard Projectiles there are also three modes, mushrooming, shearing cracking and fragmentation.
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NUMERICAL STUDY ON THE HIGH‐SPEED WATER‐ENTRY BEHAVIORS OF CYLINDRICAL, HEMISPHERICAL AND CONICAL ProjectileS
2009Co-Authors: Zitao Guo, Wei Zhang, Shuping Luan, Xinke XiaoAbstract:The water entry problem is considered as a classic problem which has a research history of more than 70 years, the water‐entry process for Projectiles with different nose will be significant for related application and experimental design. In this paper, a series of numerical simulations were conducted to study the water‐entry behaviors of cylindrical, hemispherical and conical Projectiles using the coupled Lagrange‐Euler technology in the non‐linear finite element code AUTODYN‐2D. The detailed cavity expansion process and the cavity characteristics of three Projectiles in the early stages of water‐entry were obtained. The effects of the Projectile nose shape and the Projectile velocity on the cavity shapes were studied. Simultaneously, the laws of velocity attenuations for three Projectiles were also proposed in this study. The results show that cylindrical Projectile has the minimum ratio of the cavity length to the cavity half thickness among the three Projectiles when they have identical impact veloci...
Wei Zhang - One of the best experts on this subject based on the ideXlab platform.
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An investigation into horizontal water entry behaviors of Projectiles with different nose shapes
International Journal of Impact Engineering, 2012Co-Authors: Zitao Guo, Wei Zhang, Xinke Xiao, Gang Wei, Peng RenAbstract:Abstract In the present study, high-speed horizontal water entry behaviors of flat, ogival and hemispherical-nose Projectiles were studied experimentally and theoretically. Particular attention is given to characterizing the Projectile dynamics and the cavity evolution before a deep pinching starts. An analytical cavity model based on the solution to the Rayleigh–Besant problem was developed to describe the cavity dynamics of Projectile water entry. Three parameters in the cavity model were discussed and determined theoretically and experimentally. Numerical simulations using the AUTODYN-2D Lagrange–Euler coupling techniques were conducted to specially study the drag coefficients of Projectiles. Based on the experimental and numerical results, a drag coefficient model independent on the cavitation number was proposed. The results indicated that there are two variation laws for the three parameters in the cavity model; Additionally, the drag coefficients increase with the impact velocities with holding the Projectile nose constant and decrease with an increase in the Projectile nose coefficient (CRH) value. Good agreements were observed between analytical results and experimental observations.
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effect of Projectile hardness on deformation and fracture behavior in the taylor impact test
Materials & Design, 2010Co-Authors: Xinke Xiao, Wei Zhang, Zhongcheng MuAbstract:Abstract The ballistic perforation performance of a kinetic energy Projectile would be much more influenced by the Projectile’s deformation during the impact process. A Projectile may suffer from large deformation and even fracture as more and more advanced materials are used as resistant components. A comparison investigation was presented in this study concerning the deformation and fracture behavior of kinetic energy Projectiles manufactured from 38CrSi steel of two different hardness values. Flat-nosed Projectiles were fired in a two-stage compressed gun test facility against hard steel plates within the velocity range of 200–600 m/s. The impact process was monitored by a high-speed camera. Experimental results showed that, for the soft Projectiles there are three deformation and fracture modes, i.e., mushrooming, shear cracking and petalling, and that for the hard Projectiles there are also three modes, mushrooming, shearing cracking and fragmentation.
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NUMERICAL STUDY ON THE HIGH‐SPEED WATER‐ENTRY BEHAVIORS OF CYLINDRICAL, HEMISPHERICAL AND CONICAL ProjectileS
2009Co-Authors: Zitao Guo, Wei Zhang, Shuping Luan, Xinke XiaoAbstract:The water entry problem is considered as a classic problem which has a research history of more than 70 years, the water‐entry process for Projectiles with different nose will be significant for related application and experimental design. In this paper, a series of numerical simulations were conducted to study the water‐entry behaviors of cylindrical, hemispherical and conical Projectiles using the coupled Lagrange‐Euler technology in the non‐linear finite element code AUTODYN‐2D. The detailed cavity expansion process and the cavity characteristics of three Projectiles in the early stages of water‐entry were obtained. The effects of the Projectile nose shape and the Projectile velocity on the cavity shapes were studied. Simultaneously, the laws of velocity attenuations for three Projectiles were also proposed in this study. The results show that cylindrical Projectile has the minimum ratio of the cavity length to the cavity half thickness among the three Projectiles when they have identical impact veloci...
N K Gupta - One of the best experts on this subject based on the ideXlab platform.
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experimental and numerical studies of double nosed Projectile impact on aluminum plates
International Journal of Impact Engineering, 2013Co-Authors: M A Iqbal, Sanan H Khan, Raisuddin Ansari, N K GuptaAbstract:Abstract Experiments and numerical simulations were performed to study the failure modes and ballistic resistance of aluminum targets subjected to normal impact of double-nosed Projectiles. Three such Projectiles used in this study were designated according to their front and second nose shapes as conico–blunt, blunt–blunt and blunt–conico. Each Projectile was hit normally on 0.82 and 1.82 mm thick circular plate targets of 1100-H14 aluminium at different velocities. The deformation, failure mode and ballistic limit of both targets were obtained through experiments and reproduced through simulations using ABAQUS/Explicit finite element code. The ballistic limit of target was found to be highest against blunt–blunt followed by conico–blunt and blunt–conico Projectile respectively. The results of target response thus obtained due to the impact of the double-nosed Projectiles were compared with those of the single-nosed blunt and conical Projectiles, and typical features of the plate response have been discussed for both double and single-nosed Projectiles.
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energy absorption capability of thin laminates subjected to heavy mass Projectile impact of varying nose geometries
International Journal of Crashworthiness, 2008Co-Authors: M G Babu, R Velmurugan, N K GuptaAbstract:Abstract This study evaluates the energy absorption, perforation and damage evolution created by cylindrical Projectile of different nose geometries in woven roving mat/epoxy laminates with 0.45° orientation. A series of ballistic impact tests have been carried out on the laminate with Projectile nose geometries representing hemispherical, conical, and conical with round nose and truncated tip. A gas gun Projectile launcher set-up was employed to impact the target at different speeds. The damage pattern, perforation mechanism and ballistic limit for each type of Projectiles have been studied. Truncated-nose Projectile shows the highest ballistic limit while sharp-nose shows the lowest. A quasi-static punch test was carried out on targets with Projectiles of above-mentioned nose geometries to assess the damage evolution at a constant strain rate. The maximum load required to cause perforation during punch test was noted for hemispherical-nose Projectile. An in-depth layerwise analysis was carried out to an...
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effect of Projectile nose shape impact velocity and target thickness on deformation behavior of aluminum plates
International Journal of Solids and Structures, 2007Co-Authors: N K Gupta, M A Iqbal, G S SekhonAbstract:The present study deals with the experimental and numerical investigations of aluminum target plates impacted by blunt, ogive and hemispherical nosed steel Projectiles. The Projectiles were normally impacted on the target plates of 0.5, 0.71, 1, 1.5, 2, 2.5 and 3 mm thicknesses at different velocities with the help of a pneumatic gun. Effect of Projectile nose shape, impact velocity and plate thickness on the deformation of the target plates was studied. Hemispherical nosed Projectile caused highest global deformation (dishing) of the target plates. Ogive nosed Projectiles were found to be the most efficient penetrator for the case of plates of thicknesses 0.5, 0.71, 1.0 and 1.5 mm. For the case of plates of thicknesses 2.0, 2.5 and 3.0 mm however, blunt nosed Projectiles required least energy to perforate the target plates. The ballistic limit velocity of hemispherical nosed Projectiles was found to be highest as compared to the other two Projectiles. Finite element analysis of the problem was carried out using ABAQUS finite element code. Results of the numerical analysis were compared with the experiments and good correlation between the two was found.
Zitao Guo - One of the best experts on this subject based on the ideXlab platform.
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An investigation into horizontal water entry behaviors of Projectiles with different nose shapes
International Journal of Impact Engineering, 2012Co-Authors: Zitao Guo, Wei Zhang, Xinke Xiao, Gang Wei, Peng RenAbstract:Abstract In the present study, high-speed horizontal water entry behaviors of flat, ogival and hemispherical-nose Projectiles were studied experimentally and theoretically. Particular attention is given to characterizing the Projectile dynamics and the cavity evolution before a deep pinching starts. An analytical cavity model based on the solution to the Rayleigh–Besant problem was developed to describe the cavity dynamics of Projectile water entry. Three parameters in the cavity model were discussed and determined theoretically and experimentally. Numerical simulations using the AUTODYN-2D Lagrange–Euler coupling techniques were conducted to specially study the drag coefficients of Projectiles. Based on the experimental and numerical results, a drag coefficient model independent on the cavitation number was proposed. The results indicated that there are two variation laws for the three parameters in the cavity model; Additionally, the drag coefficients increase with the impact velocities with holding the Projectile nose constant and decrease with an increase in the Projectile nose coefficient (CRH) value. Good agreements were observed between analytical results and experimental observations.
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NUMERICAL STUDY ON THE HIGH‐SPEED WATER‐ENTRY BEHAVIORS OF CYLINDRICAL, HEMISPHERICAL AND CONICAL ProjectileS
2009Co-Authors: Zitao Guo, Wei Zhang, Shuping Luan, Xinke XiaoAbstract:The water entry problem is considered as a classic problem which has a research history of more than 70 years, the water‐entry process for Projectiles with different nose will be significant for related application and experimental design. In this paper, a series of numerical simulations were conducted to study the water‐entry behaviors of cylindrical, hemispherical and conical Projectiles using the coupled Lagrange‐Euler technology in the non‐linear finite element code AUTODYN‐2D. The detailed cavity expansion process and the cavity characteristics of three Projectiles in the early stages of water‐entry were obtained. The effects of the Projectile nose shape and the Projectile velocity on the cavity shapes were studied. Simultaneously, the laws of velocity attenuations for three Projectiles were also proposed in this study. The results show that cylindrical Projectile has the minimum ratio of the cavity length to the cavity half thickness among the three Projectiles when they have identical impact veloci...
Anand Sarma - One of the best experts on this subject based on the ideXlab platform.
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Projectile penetration into sand: Relative density of sand and Projectile nose shape and mass
International Journal of Impact Engineering, 2017Co-Authors: Siau Chen Chian, Beng Chye Vincent Tan, Anand SarmaAbstract:Abstract Compacted granular materials, like sand, have a tendency to dilate and expand under shear loading. Such tendency of dilation is beneficial to inhibit Projectile penetration. Furthermore, the higher the striking velocity of a given Projectile, the higher is the peak strength of the sand sample. Different nose shapes (spherical, flat, hemispherical, conical and ogival) and mass (7 g, 15 g and 20 g) of Projectiles were fired into sand samples of relative densities ranging from medium dense to very dense state (60%, 75% and 90%). Results showed that the pointed ogival head Projectile had the lowest ballistic limit, whereas the blunt flat head Projectile required the highest ballistic energy to defeat the sand block. Despite visible effect of nose shape, the mass of Projectile has a larger influence on the amount of absorbed energy. On the other hand, initial compaction of the sand alters the depth of penetration marginally. This is attributed to the Projectile impact which compacts the sand as the Projectile penetrates through the sand sample. A strong linear correlation between Projectile nose shape, mass and ballistic impact energy was established in this study, which allows protective engineers to easily design sand barriers to defeat a range of Projectiles. Furthermore, it was found that the energy absorption of sand remains high even when subjected to striking velocities way beyond its ballistic limit. This opens up avenues for sand barriers to be used as sacrificial layer of a composite lightweight protective barrier.
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Reprint of: Projectile penetration into sand: Relative density of sand and Projectile nose shape and mass
International Journal of Impact Engineering, 2017Co-Authors: Siau Chen Chian, Beng Chye Vincent Tan, Anand SarmaAbstract:Abstract Compacted granular materials, like sand, have a tendency to dilate and expand under shear loading. Such tendency of dilation is beneficial to inhibit Projectile penetration. Furthermore, the higher the striking velocity of a given Projectile, the higher is the peak strength of the sand sample. Different nose shapes (spherical, flat, hemispherical, conical and ogival) and mass (7 g, 15 g and 20 g) of Projectiles were fired into sand samples of relative densities ranging from medium dense to very dense state (60%, 75% and 90%). Results showed that the pointed ogival head Projectile had the lowest ballistic limit, whereas the blunt flat head Projectile required the highest ballistic energy to defeat the sand block. Despite visible effect of nose shape, the mass of Projectile has a larger influence on the amount of absorbed energy. On the other hand, initial compaction of the sand alters the depth of penetration marginally. This is attributed to the Projectile impact which compacts the sand as the Projectile penetrates through the sand sample. A strong linear correlation between Projectile nose shape, mass and ballistic impact energy was established in this study, which allows protective engineers to easily design sand barriers to defeat a range of Projectiles. Furthermore, it was found that the energy absorption of sand remains high even when subjected to striking velocities way beyond its ballistic limit. This opens up avenues for sand barriers to be used as sacrificial layer of a composite lightweight protective barrier.
