2013 Vol. 33, No. 1
Display Method:
2013, 33(1): 1-10.
doi: 10.11883/1001-1455(2013)01-0001-10
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Abstract:
Based on the ZWT viscoelastic constitutive relation, the governing equations which reflect high-strain-rate effects, for viscoelastic spherical waves are established, including five partial differential equations to solve five unknown variables such as v, r, , r and . By using the characteristics method, the problem is reduced to solve five ordinary differential equations along three sets of characteristics. The numerical results by the characteristics method show that the degree of attenuation and dispersion for viscoelastic spherical waves are more remarkable than those of linear elastic spherical waves. The tangential tensile stress/strain induced by the surface extension of spherical wave front plays a significant role in tensile failure of medium, while the constitutive viscosity can relieve the tensile stress/strain. An analytic expression for the attenuation of strongdiscontinuous viscoelastic spherical wave front is further derived, which analytically illustrates that the more remarkable attenuation of strongdiscontinuous viscoelastic spherical wave front is resulted from the combined effects of both the geometrical extension effect and the constitutive viscosity effect.
Based on the ZWT viscoelastic constitutive relation, the governing equations which reflect high-strain-rate effects, for viscoelastic spherical waves are established, including five partial differential equations to solve five unknown variables such as v, r, , r and . By using the characteristics method, the problem is reduced to solve five ordinary differential equations along three sets of characteristics. The numerical results by the characteristics method show that the degree of attenuation and dispersion for viscoelastic spherical waves are more remarkable than those of linear elastic spherical waves. The tangential tensile stress/strain induced by the surface extension of spherical wave front plays a significant role in tensile failure of medium, while the constitutive viscosity can relieve the tensile stress/strain. An analytic expression for the attenuation of strongdiscontinuous viscoelastic spherical wave front is further derived, which analytically illustrates that the more remarkable attenuation of strongdiscontinuous viscoelastic spherical wave front is resulted from the combined effects of both the geometrical extension effect and the constitutive viscosity effect.
2013, 33(1): 11-20.
doi: 10.11883/1001-1455(2013)01-0011-10
Abstract:
The method of characteristics was used to analyze the stress wave propagations in the brittle materials. The random nucleation and the growth of the cracks in the brittle materials were described by using the cohesive fracture model. A practical simulation tool, ExpRing was developed for simulating the fracture and fragmentation in an expanding brittle ring. The ExpRing code was briefly explained. By using this code, the fragmentations of the rings with different intrinsic defects were simulated. The calculation results show: (1) within a certain strainrate range, the equally-spaced point defects will control the final fracture sites and the fragment sizes and it can induce a defect-controlled-fragmentation (DCF) platform in the relation curve between the fragment size and the strain rate; (2) the spacing and the magnitude of the defects will alter the width and the location of the DCF platform; (3) the strength of the brittle materials with initial defects exhibit an apparent strain-rate effect. And further study displays that the materials with sinuouslydistributed defects exhibit similar fragmentation behaviors to the materials with equally-spaced point defects.
The method of characteristics was used to analyze the stress wave propagations in the brittle materials. The random nucleation and the growth of the cracks in the brittle materials were described by using the cohesive fracture model. A practical simulation tool, ExpRing was developed for simulating the fracture and fragmentation in an expanding brittle ring. The ExpRing code was briefly explained. By using this code, the fragmentations of the rings with different intrinsic defects were simulated. The calculation results show: (1) within a certain strainrate range, the equally-spaced point defects will control the final fracture sites and the fragment sizes and it can induce a defect-controlled-fragmentation (DCF) platform in the relation curve between the fragment size and the strain rate; (2) the spacing and the magnitude of the defects will alter the width and the location of the DCF platform; (3) the strength of the brittle materials with initial defects exhibit an apparent strain-rate effect. And further study displays that the materials with sinuouslydistributed defects exhibit similar fragmentation behaviors to the materials with equally-spaced point defects.
2013, 33(1): 21-28.
doi: 10.11883/1001-1455(2013)01-0021-08
Abstract:
An experimental device with an explosive-driven flyer plate was designed for shock initiation of the explosives at elevated temperatures. This device can heat up the acceptor explosives uniformly and keep the donor explosives out of the heating. Based on this device, the shock initiation tests were conducted for the HMX/TATB composite explosive heated to different temperatures: 14, 100, 140, 160 as well as 180 ℃, and the in-situ pressure histories were measured at various depths of the explosives. The ignition and growth reaction rate equation was used to numerically simulate the shock initiation of the explosive. Based on the experimental results, the parameters were determined for the ignition and growth reaction rate equation of the explosive shock initiation at different temperatures, the relationships were given between the model parameters and temperature, and the Pop relationships of the explosive at different temperatures were given. The results show that the shock sensitivity of the HMX/TATB composite explosive increases with an increase in the temperature, but its dependence on temperature is less than that of the HMX explosive in that the TATB explosive in the composite explosive has good desensitizing effect.
An experimental device with an explosive-driven flyer plate was designed for shock initiation of the explosives at elevated temperatures. This device can heat up the acceptor explosives uniformly and keep the donor explosives out of the heating. Based on this device, the shock initiation tests were conducted for the HMX/TATB composite explosive heated to different temperatures: 14, 100, 140, 160 as well as 180 ℃, and the in-situ pressure histories were measured at various depths of the explosives. The ignition and growth reaction rate equation was used to numerically simulate the shock initiation of the explosive. Based on the experimental results, the parameters were determined for the ignition and growth reaction rate equation of the explosive shock initiation at different temperatures, the relationships were given between the model parameters and temperature, and the Pop relationships of the explosive at different temperatures were given. The results show that the shock sensitivity of the HMX/TATB composite explosive increases with an increase in the temperature, but its dependence on temperature is less than that of the HMX explosive in that the TATB explosive in the composite explosive has good desensitizing effect.
2013, 33(1): 29-37.
doi: 10.11883/1001-1455(2013)01-0029-09
Abstract:
In order to avoid the difficulties of the original ghost fluid method (GFM) in simulating the interaction between shock wave and material (fluid-fluid, gas-water) interface with large density ratio, the real ghost fluid method (RGFM) was adopted to treat the ghost points near the material interface, the HLLC (Harten-Lax-Van Leer with contact discontinuities) Riemann solver was applied to solve the Euler equations, and the fifth-order weighted essentially nonoscillatory (WENO) scheme was implemented to solve the level set equation. Numerical simulations were carried out for one-dimensional and twodimensional examples, respectively. Simulated results show that the RGFM is superior to the GFM, and the images by the RGFM can display more details of the interaction between shock wave and material interface, which include the distinct deformation and fragmentation of the material interfaces with high density ratios.
In order to avoid the difficulties of the original ghost fluid method (GFM) in simulating the interaction between shock wave and material (fluid-fluid, gas-water) interface with large density ratio, the real ghost fluid method (RGFM) was adopted to treat the ghost points near the material interface, the HLLC (Harten-Lax-Van Leer with contact discontinuities) Riemann solver was applied to solve the Euler equations, and the fifth-order weighted essentially nonoscillatory (WENO) scheme was implemented to solve the level set equation. Numerical simulations were carried out for one-dimensional and twodimensional examples, respectively. Simulated results show that the RGFM is superior to the GFM, and the images by the RGFM can display more details of the interaction between shock wave and material interface, which include the distinct deformation and fragmentation of the material interfaces with high density ratios.
2013, 33(1): 38-46.
doi: 10.11883/1001-1455(2013)01-0038-09
Abstract:
The formation process of explosively formed penetrators (EFPs) with fins formed by three-point initiation was simulated by using LS-DYNA software. The structure and intensity of detonation waves in the transmitting process as well as the distortion characters of the liner formed by the composite detonation waves were theoretically studied to deeply understand the formation mechanism of EFPs with fins. The threepoint initiation device was designed and the EFP charges were tested. The results show that the designed three-point initiation device is reliable and can meet design requirements of EFP charges, and the shapes of the EFPs obtained in the experiments are stable which are in agreement with the simulations. And the speed drops of the EFPs with fins in the fly processes decrease and the stabilities increase.
The formation process of explosively formed penetrators (EFPs) with fins formed by three-point initiation was simulated by using LS-DYNA software. The structure and intensity of detonation waves in the transmitting process as well as the distortion characters of the liner formed by the composite detonation waves were theoretically studied to deeply understand the formation mechanism of EFPs with fins. The threepoint initiation device was designed and the EFP charges were tested. The results show that the designed three-point initiation device is reliable and can meet design requirements of EFP charges, and the shapes of the EFPs obtained in the experiments are stable which are in agreement with the simulations. And the speed drops of the EFPs with fins in the fly processes decrease and the stabilities increase.
2013, 33(1): 47-53.
doi: 10.11883/1001-1455(2013)01-0047-07
Abstract:
The radial impact responses of TiNi alloy cylindrical shells with phase transformation were investigated experimentally by using a modified split Hopkinson pressure bar (SHPB) apparatus and a high-speed charged-coupled device (CCD) camera. The dynamic load-displacement curves of the structure were obtained. Based on the pure bending assumption, the dynamic deformation process of the whole structure was analyzed quantitatively by adopting the digital pickup technique. The results show that a cylindrical shell with phase transition can recover its original shape after impact, its nonlinear loading-unloading behavior is related to the state of phase transition and the evolution of phase transition hinges. Meanwhile, this structure has a fine radial shock resistance effect, the impact acceleration and load can be attenuated to less than 5% and the rate of energy dissipation is 42.4%, and it is hopefully applied in the shock absorber devices subjected to multiple impacts.
The radial impact responses of TiNi alloy cylindrical shells with phase transformation were investigated experimentally by using a modified split Hopkinson pressure bar (SHPB) apparatus and a high-speed charged-coupled device (CCD) camera. The dynamic load-displacement curves of the structure were obtained. Based on the pure bending assumption, the dynamic deformation process of the whole structure was analyzed quantitatively by adopting the digital pickup technique. The results show that a cylindrical shell with phase transition can recover its original shape after impact, its nonlinear loading-unloading behavior is related to the state of phase transition and the evolution of phase transition hinges. Meanwhile, this structure has a fine radial shock resistance effect, the impact acceleration and load can be attenuated to less than 5% and the rate of energy dissipation is 42.4%, and it is hopefully applied in the shock absorber devices subjected to multiple impacts.
2013, 33(1): 54-60.
doi: 10.11883/1001-1455(2013)01-0054-07
Abstract:
To study the dynamic mechanical properties of material at high temperatures, a new high-temperature split Hopkinson pressure bar (SHPB) system was proposed by combining a self-developed temperature-controlling system and an ordinary 100-mm-diameter SHPB system. The ANSYS software was used to analyze the interface heat transfer phenomenon and its influences on the experimental results. The reliability of the experimental technique proposed was demonstrated. And the experimental technique proposed was utilized to investigate the dynamic mechanical properties of concrete at high temperatures. The results show that for the high temperature impact tests on heat-inertia materials such as concrete using the large-diameter SHPB made of alloy steels, the critical value of cold contact time (CCT) is 1.00 s, and the CCT for the experimental technique proposed does not exceed 0.50 s, the experimental technique proposed is credible; and that at invariable loading rate with temperature increasing gradually from normal temperature to 1 000 ℃, the dynamic stress-strain curves of concrete exhibit gradually plasticity properties, the dynamic compressive strength first rises, then falls, and the dynamic peak strain rises constantly.
To study the dynamic mechanical properties of material at high temperatures, a new high-temperature split Hopkinson pressure bar (SHPB) system was proposed by combining a self-developed temperature-controlling system and an ordinary 100-mm-diameter SHPB system. The ANSYS software was used to analyze the interface heat transfer phenomenon and its influences on the experimental results. The reliability of the experimental technique proposed was demonstrated. And the experimental technique proposed was utilized to investigate the dynamic mechanical properties of concrete at high temperatures. The results show that for the high temperature impact tests on heat-inertia materials such as concrete using the large-diameter SHPB made of alloy steels, the critical value of cold contact time (CCT) is 1.00 s, and the CCT for the experimental technique proposed does not exceed 0.50 s, the experimental technique proposed is credible; and that at invariable loading rate with temperature increasing gradually from normal temperature to 1 000 ℃, the dynamic stress-strain curves of concrete exhibit gradually plasticity properties, the dynamic compressive strength first rises, then falls, and the dynamic peak strain rises constantly.
2013, 33(1): 61-66.
doi: 10.11883/1001-1455(2013)01-0061-06
Abstract:
Based on the 2D Euler equations, the shock wave propagation through the tube with rectangular grooves was numerically simulated by combining the fifth-order weighted essentially nonoscillatory (WENO) scheme and the adaptive mesh refinement (AMR) technique. The numerical results display the interaction of the incident shock wave with the grooves during its propagation inside the tube as well as its evolution within every single groove, and agree with the existent experimental results by N. Gongora-Orozco, et al. In addition, the numerical results reveal that the phenomena of expansion wave induced by shock wave diffraction and reflected shock wave due to collision appear during the interaction of the incident wave with a single groove. The expansion wave attenuates the incident shock wave, the reflected wave amplifies its intensity, but the attenuation effect dominates the process, resulting in the front intensity decrease of the incident wave in a vibrating way.
Based on the 2D Euler equations, the shock wave propagation through the tube with rectangular grooves was numerically simulated by combining the fifth-order weighted essentially nonoscillatory (WENO) scheme and the adaptive mesh refinement (AMR) technique. The numerical results display the interaction of the incident shock wave with the grooves during its propagation inside the tube as well as its evolution within every single groove, and agree with the existent experimental results by N. Gongora-Orozco, et al. In addition, the numerical results reveal that the phenomena of expansion wave induced by shock wave diffraction and reflected shock wave due to collision appear during the interaction of the incident wave with a single groove. The expansion wave attenuates the incident shock wave, the reflected wave amplifies its intensity, but the attenuation effect dominates the process, resulting in the front intensity decrease of the incident wave in a vibrating way.
2013, 33(1): 67-72.
doi: 10.11883/1001-1455(2013)01-0067-06
Abstract:
A schlieren apparatus was established to experimentally evaluate the influences of the shock wave formed by the explosion of the cold shock wave extinguishing bomb on the extinguishing effect and the surrounding environment. The shock waves formed by the explosion and dispersion of the different extinguishing media and the corresponding propagations were observed based on the abovementioned schlieren apparatus. And the particle velocity behind the shock wave front at the edge of the oil pool after the explosion of the cold shock wave extinguishing bomb was calculated. Observation shows that the waterbased fireextinguishing medium can not form shock wave; and the powderbased fireextinguishing medium can form shock wave, but its strength is weak and the particle velocity is low at the edge of the oil pool. Compared with the movement of the combustible gas induced by the medium dispersion, the movement of the combustible gas induced by the shock wave may be neglected. Finally, the above conclusion was verified by a highspeed photographic experiment. So for the cold shock wave fireextinguishing system, the influences of the shock wave on the extinguishing effect and the surrounding environment are neglectable.
A schlieren apparatus was established to experimentally evaluate the influences of the shock wave formed by the explosion of the cold shock wave extinguishing bomb on the extinguishing effect and the surrounding environment. The shock waves formed by the explosion and dispersion of the different extinguishing media and the corresponding propagations were observed based on the abovementioned schlieren apparatus. And the particle velocity behind the shock wave front at the edge of the oil pool after the explosion of the cold shock wave extinguishing bomb was calculated. Observation shows that the waterbased fireextinguishing medium can not form shock wave; and the powderbased fireextinguishing medium can form shock wave, but its strength is weak and the particle velocity is low at the edge of the oil pool. Compared with the movement of the combustible gas induced by the medium dispersion, the movement of the combustible gas induced by the shock wave may be neglected. Finally, the above conclusion was verified by a highspeed photographic experiment. So for the cold shock wave fireextinguishing system, the influences of the shock wave on the extinguishing effect and the surrounding environment are neglectable.
2013, 33(1): 73-78.
doi: 10.11883/1001-1455(2013)01-0073-06
Abstract:
Four kinds of finite thickness target plates were prepared, including granite (G) plates, steel wire-mesh reinforced concrete (RC) plates, composite GRC targets composed by granite (G) plates and steel wire-mesh reinforced concrete (RC) plates, and composite GBRC targets composed by granite block (GB)masonry and steel wire-mesh reinforced concrete (RC) plates. By using a 30-mm-caliber gun to accelerate two kinds of projectiles of the same shape which differ in material strength, penetration experiments were carried out for these prepared target plates, respectively. The damage effects of the target plates subjected to projectile penetration were compared. The results show that the well-designed GBRC targets have the best resistance to perforation. And the perforation resistance of the GBRC targets is closely related with the following factors: block stone size, strength, masonry way, and reinforced concrete structure.
Four kinds of finite thickness target plates were prepared, including granite (G) plates, steel wire-mesh reinforced concrete (RC) plates, composite GRC targets composed by granite (G) plates and steel wire-mesh reinforced concrete (RC) plates, and composite GBRC targets composed by granite block (GB)masonry and steel wire-mesh reinforced concrete (RC) plates. By using a 30-mm-caliber gun to accelerate two kinds of projectiles of the same shape which differ in material strength, penetration experiments were carried out for these prepared target plates, respectively. The damage effects of the target plates subjected to projectile penetration were compared. The results show that the well-designed GBRC targets have the best resistance to perforation. And the perforation resistance of the GBRC targets is closely related with the following factors: block stone size, strength, masonry way, and reinforced concrete structure.
2013, 33(1): 79-84.
doi: 10.11883/1001-1455(2013)01-0079-06
Abstract:
Based on the molecular structural descriptors as follows: intramolecular hydrogen bond, molecular structure, symmetry, oxygen balance, activity index, crowded degree and so on, the step wise regression (SWR) and support vector regression (SVR) approaches were proposed to model the relationship between the descriptors and the impact sensitivity for 156 nitro energetic compounds. The SWR and SVR models were further validated and compared by using 8 independent test samples. The results reveal that lgH50 exhibits a strong negative correlation with the oxygen balance (OB100) and the activity index (F), the more the chemical groups linked with a carbon atom, the greater the impact sensitivity of the explosive; that the trigger bonds of -CH or -OH can cause H50 to decrease; and that the more the intra-molecular hydrogen bonds in unit mass of explosive, the lower the impact sensitivity. The modeling ability of the SVR approach surpasses that of the multiple linear regression (MLR) approach and its prediction accuracy is also superior to that of the MLR approach, which was validated by using the identical training set and test set. The above investigated results demonstrate that the SVR approach is an effective tool to predict the impact sensitivity of explosives and can provide an important theoretical guidance for the design/synthesis of insensitive high energetic explosive.
Based on the molecular structural descriptors as follows: intramolecular hydrogen bond, molecular structure, symmetry, oxygen balance, activity index, crowded degree and so on, the step wise regression (SWR) and support vector regression (SVR) approaches were proposed to model the relationship between the descriptors and the impact sensitivity for 156 nitro energetic compounds. The SWR and SVR models were further validated and compared by using 8 independent test samples. The results reveal that lgH50 exhibits a strong negative correlation with the oxygen balance (OB100) and the activity index (F), the more the chemical groups linked with a carbon atom, the greater the impact sensitivity of the explosive; that the trigger bonds of -CH or -OH can cause H50 to decrease; and that the more the intra-molecular hydrogen bonds in unit mass of explosive, the lower the impact sensitivity. The modeling ability of the SVR approach surpasses that of the multiple linear regression (MLR) approach and its prediction accuracy is also superior to that of the MLR approach, which was validated by using the identical training set and test set. The above investigated results demonstrate that the SVR approach is an effective tool to predict the impact sensitivity of explosives and can provide an important theoretical guidance for the design/synthesis of insensitive high energetic explosive.
2013, 33(1): 85-90.
doi: 10.11883/1001-1455(2013)01-0085-06
Abstract:
An experimental apparatus was developed for measuring the parameters for the blast waves produced by a high-voltage spark discharge. To investigate the variation and propagation tendency of the blast wave and the scaling law of its parameters, the pressure and arrival time of the blast wave in air were measured at different radii and initial energy using a PCB piezoelectric pressure transducer. The results show that the high-voltage spark-produced blast wave follows the Hopkinson-Sachs scaling law. The comparison between the experimental results and the numerical simulation for a spherical blast wave from a point energy source confirms that the blast wave originated from the high-voltage capacitor spark discharge follows adequately the analytical description and the amount of energy contributed to the direct blast initiation from the spark ignition can be estimated from the first 1/4 cycle current discharge. The composition of the total energy stored in the capacitors, (i.e., 1/2CU2) was further investigated. The results indicate that about 91% of the total energy wastes on the energy loss and ohmic dissipation, and only about 2% contributes to the first 1/4 cycle current discharge energy which is responsible to initiate the detonation. The energy released after the first 1/4 cycle only tends to heat up the surrounding gases.
An experimental apparatus was developed for measuring the parameters for the blast waves produced by a high-voltage spark discharge. To investigate the variation and propagation tendency of the blast wave and the scaling law of its parameters, the pressure and arrival time of the blast wave in air were measured at different radii and initial energy using a PCB piezoelectric pressure transducer. The results show that the high-voltage spark-produced blast wave follows the Hopkinson-Sachs scaling law. The comparison between the experimental results and the numerical simulation for a spherical blast wave from a point energy source confirms that the blast wave originated from the high-voltage capacitor spark discharge follows adequately the analytical description and the amount of energy contributed to the direct blast initiation from the spark ignition can be estimated from the first 1/4 cycle current discharge. The composition of the total energy stored in the capacitors, (i.e., 1/2CU2) was further investigated. The results indicate that about 91% of the total energy wastes on the energy loss and ohmic dissipation, and only about 2% contributes to the first 1/4 cycle current discharge energy which is responsible to initiate the detonation. The energy released after the first 1/4 cycle only tends to heat up the surrounding gases.
2013, 33(1): 91-97.
doi: 10.11883/1001-1455(2013)01-0091-07
Abstract:
Based on the blasting vibration monitoring data of Dahuanggou highway tunnels from Dandong to Tonghua, the FLAC-3D software was used to analyze the displacement responses of Dahuanggou tunnel surrounding rock with small clearance under blast loads. According to the monitoring data of the blasting vibration particles，the displacement responses of the surrounding rock, of which the left and right tunnels were subjected to circular blasting excavation with six times in all, were simulated by considering the coupling effect of the vertical and horizontal particle vibrations. And the acoustic wave velocities of the surrounding rock were experimentally measured. The simulated results were compared with the measured results. Comparisons show that with the progress of the circular blasting excavation, the surrounding rock is stable, and the damage and displacement offset of the surrounding rock take on certain symmetry by taking the middle column as an axis and getting rid of the effects of the blast load sequence undergone by the left and right tunnels. And with the progress of the blasting excavation, the distances of the monitoring points away from the explosion center increase, the blastinduced stress waves weaken at the monitoring points, the fatigue damage and displacement offset increment of the surrounding rock decrease and it tends to a stable state eventually.
Based on the blasting vibration monitoring data of Dahuanggou highway tunnels from Dandong to Tonghua, the FLAC-3D software was used to analyze the displacement responses of Dahuanggou tunnel surrounding rock with small clearance under blast loads. According to the monitoring data of the blasting vibration particles，the displacement responses of the surrounding rock, of which the left and right tunnels were subjected to circular blasting excavation with six times in all, were simulated by considering the coupling effect of the vertical and horizontal particle vibrations. And the acoustic wave velocities of the surrounding rock were experimentally measured. The simulated results were compared with the measured results. Comparisons show that with the progress of the circular blasting excavation, the surrounding rock is stable, and the damage and displacement offset of the surrounding rock take on certain symmetry by taking the middle column as an axis and getting rid of the effects of the blast load sequence undergone by the left and right tunnels. And with the progress of the blasting excavation, the distances of the monitoring points away from the explosion center increase, the blastinduced stress waves weaken at the monitoring points, the fatigue damage and displacement offset increment of the surrounding rock decrease and it tends to a stable state eventually.
2013, 33(1): 98-102.
doi: 10.11883/1001-1455(2013)01-0098-05
Abstract:
A metallic penetrator with the mass of 52 kg was designed by considering reasonably its structure and head shape. Based on the sub-caliber launch technology, the designed penetrator was accelerated to 1 300 m/s by a Davis gun to experimentally penetrate a six-layer reinforced concrete target with the size of 3.0 m3.0 m6.0 m. The penetration experiment displays that the sub-caliber penetrator departed distinctly from the Davis gun，its flight attitude was stable, the attack angle was less than 2, and the residual velocity was about 260 m/s after the penetration of the penetrator into the reinforced concrete of 6 m thickness. After the penetration experiment, the recovered penetrator was intact and only a little plastic deformation on the penetrator head. And the penetrator mass lost around 1.2 percent, its length shortened 0.7 percent, and the erosion phenomenon was unconspicuous.
A metallic penetrator with the mass of 52 kg was designed by considering reasonably its structure and head shape. Based on the sub-caliber launch technology, the designed penetrator was accelerated to 1 300 m/s by a Davis gun to experimentally penetrate a six-layer reinforced concrete target with the size of 3.0 m3.0 m6.0 m. The penetration experiment displays that the sub-caliber penetrator departed distinctly from the Davis gun，its flight attitude was stable, the attack angle was less than 2, and the residual velocity was about 260 m/s after the penetration of the penetrator into the reinforced concrete of 6 m thickness. After the penetration experiment, the recovered penetrator was intact and only a little plastic deformation on the penetrator head. And the penetrator mass lost around 1.2 percent, its length shortened 0.7 percent, and the erosion phenomenon was unconspicuous.
2013, 33(1): 103-107.
doi: 10.11883/1001-1455(2013)01-0103-05
Abstract:
The applications of underwater explosion in military and economic development were reviewed and its potential application in industry was explored. Based on the unique properties of underwater shock waves, the underwater explosive welding and underwater explosive compaction were advanced. The characteristic wavy morphology observed in the scanning electron microscope image of the welded sample indicates that the underwater explosive welding can be an alternative bonding method for materials with thin thickness and low formability and the corresponding suitable welding parameters can be determined. The pattern of the interfacial oscillations is an indication of the bonding strength. Powder mixtures could be densified under the action of underwater shock wave and the dispersion strengthened coating on pure copper surface was prepared by using underwater explosive welding. Micro-structural characteristics display that the coating layer has a uniform and fine-grained composite structure. And the measured high hardness shows that the coating layer has sound mechanical properties.
The applications of underwater explosion in military and economic development were reviewed and its potential application in industry was explored. Based on the unique properties of underwater shock waves, the underwater explosive welding and underwater explosive compaction were advanced. The characteristic wavy morphology observed in the scanning electron microscope image of the welded sample indicates that the underwater explosive welding can be an alternative bonding method for materials with thin thickness and low formability and the corresponding suitable welding parameters can be determined. The pattern of the interfacial oscillations is an indication of the bonding strength. Powder mixtures could be densified under the action of underwater shock wave and the dispersion strengthened coating on pure copper surface was prepared by using underwater explosive welding. Micro-structural characteristics display that the coating layer has a uniform and fine-grained composite structure. And the measured high hardness shows that the coating layer has sound mechanical properties.
2013, 33(1): 108-112.
doi: 10.11883/1001-1455(2013)01-0108-05
Abstract:
A new explosive reactive armor (ERA) structure was designed. A series of dynamic analyses were carried out on the interferences of the new ERA structure with the motion velocity and attitudes of the long-rod projectiles, the corresponding dynamic equations were obtained for the long-rod projectiles in the mass conservation condition, and the protection effectiveness of the new ERA structure was experimentally validated. Investigated results show that the new ERA can disturb effectively the motion attitudes of the long-rod projectiles with small yaw angles and induce their kinetic energy decrease markedly.
A new explosive reactive armor (ERA) structure was designed. A series of dynamic analyses were carried out on the interferences of the new ERA structure with the motion velocity and attitudes of the long-rod projectiles, the corresponding dynamic equations were obtained for the long-rod projectiles in the mass conservation condition, and the protection effectiveness of the new ERA structure was experimentally validated. Investigated results show that the new ERA can disturb effectively the motion attitudes of the long-rod projectiles with small yaw angles and induce their kinetic energy decrease markedly.
