2014 Vol. 34, No. 5
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2014, 34(5): 513-520.
doi: 10.11883/1001-1455(2014)05-0513-08
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Abstract:
In order to meet the demands of transient high temperature measurement in explosive field, an infrared colorimetric temperature measurement system was established based on the theory of light radiation.The experiments with a blackbody furnace were carried out to calibrate the working parameters of the Si/Ge colorimetric pyrometer including wavelength, bandwidth, and photoelectric conversion coefficient, measurement range.And the upper limit of the colorimetric pyrometer reached 3 500℃.The response time of the colorimetric pyrometer was not more than 10μs, which was determined by calibration experiments using spark discharge.The temperature formulas were given for the standard and transfinite pyrometers.And the colorimetric pyrometer was applied to measure the real temperatures in TNT and FAE explosive fields.The outstanding features of the colorimetric pyrometer in the engineering applications indicate that the colorimetric pyrometer can be used to diagnose explosion processes and evaluate heat radiation damage effects.
In order to meet the demands of transient high temperature measurement in explosive field, an infrared colorimetric temperature measurement system was established based on the theory of light radiation.The experiments with a blackbody furnace were carried out to calibrate the working parameters of the Si/Ge colorimetric pyrometer including wavelength, bandwidth, and photoelectric conversion coefficient, measurement range.And the upper limit of the colorimetric pyrometer reached 3 500℃.The response time of the colorimetric pyrometer was not more than 10μs, which was determined by calibration experiments using spark discharge.The temperature formulas were given for the standard and transfinite pyrometers.And the colorimetric pyrometer was applied to measure the real temperatures in TNT and FAE explosive fields.The outstanding features of the colorimetric pyrometer in the engineering applications indicate that the colorimetric pyrometer can be used to diagnose explosion processes and evaluate heat radiation damage effects.
2014, 34(5): 521-526.
doi: 10.11883/1001-1455(2014)05-0521-06
Abstract:
To investigate the water-entry process of an airborne torpedo, the forces encountered by the water-entry airborne torpedo were analyzed and calculated by using MATLAB.A finite element model for the torpedo entry into water was established by using the finite element code MSC/DYTRAN.Thereby, by considering different water-entry angles and velocities, the impact forces encountered by the water-entry torpedoes were calculated as well as their corresponding pressure at the surfaces of the torpedoes for the torpedoes with different warhead shapes.The effects of water-entry angles, velocities and warhead shapes were analyzed on the maximum force and the peak pressure encountered by the water-entry torpedoes.And the water-entry trajectories of the torpedoes were discussed.The investigated results are helpful for forecasting the impact forces of water entry about the torpedoes.
To investigate the water-entry process of an airborne torpedo, the forces encountered by the water-entry airborne torpedo were analyzed and calculated by using MATLAB.A finite element model for the torpedo entry into water was established by using the finite element code MSC/DYTRAN.Thereby, by considering different water-entry angles and velocities, the impact forces encountered by the water-entry torpedoes were calculated as well as their corresponding pressure at the surfaces of the torpedoes for the torpedoes with different warhead shapes.The effects of water-entry angles, velocities and warhead shapes were analyzed on the maximum force and the peak pressure encountered by the water-entry torpedoes.And the water-entry trajectories of the torpedoes were discussed.The investigated results are helpful for forecasting the impact forces of water entry about the torpedoes.
2014, 34(5): 527-533.
doi: 10.11883/1001-1455(2014)05-0527-07
Abstract:
By considering acoustic－structure coupling, the strains, velocities and accelerations were calculated by the finite element method for the sandwich cylindrical shells as well as the common cylindrical shells having the same mass.The calculated results for the common cylindrical shells are consistent with the existent experimental results.Comparisons show that the sandwich protective layer can greatly reduce the intensity of the explosion shock wave.Resulted from the plastic deformation of the sandwich core, the explosion shock energy endured by the sandwich cylindrical shells are mostly dissipated.So the cylindrical shells in the sandwich layers can be protected.Compared with the common cylindrical shells, the sandwich layers can make the sandwich cylindrical shells endure stronger shock waves for the cylindrical shells with the same mass.Therefore, the outer sandwich layers can give a protection for the inner structures, and the sandwich cylindrical shells have good shock－resistance characteristics.
By considering acoustic－structure coupling, the strains, velocities and accelerations were calculated by the finite element method for the sandwich cylindrical shells as well as the common cylindrical shells having the same mass.The calculated results for the common cylindrical shells are consistent with the existent experimental results.Comparisons show that the sandwich protective layer can greatly reduce the intensity of the explosion shock wave.Resulted from the plastic deformation of the sandwich core, the explosion shock energy endured by the sandwich cylindrical shells are mostly dissipated.So the cylindrical shells in the sandwich layers can be protected.Compared with the common cylindrical shells, the sandwich layers can make the sandwich cylindrical shells endure stronger shock waves for the cylindrical shells with the same mass.Therefore, the outer sandwich layers can give a protection for the inner structures, and the sandwich cylindrical shells have good shock－resistance characteristics.
2014, 34(5): 534-538.
doi: 10.11883/1001-1455(2014)05-0534-05
Abstract:
Based on the large-scale finite element analysis software ANSYS/LS-DYNA, the dynamic analysis model was established for the movement of a three-dimensional rectangular high-velocity fragment in water medium.The multi-material arbitrary Lagrangian Eulerian method was used to simulate the underwater movement process of the high-velocity fragment.And the velocity attenuation curve of the fragment was given.The velocity attenuation, the mushrooming rule and the shock wave propagation process were studied.The penetration performance of the high-velocity fragment was obtained by considering its velocity change.When the initial velocity is 910-1 115m/s, the mushrooming is definite, which will increase the penetration resistance for the fragment sufficiently.When the initial velocity is low, the penetration distance of the underwater fragment will increase with the increasing of its initial velocity.When the initial velocity arrives at some critical value, the penetration distance will decrease as the initial velocity of the fragment increases.
Based on the large-scale finite element analysis software ANSYS/LS-DYNA, the dynamic analysis model was established for the movement of a three-dimensional rectangular high-velocity fragment in water medium.The multi-material arbitrary Lagrangian Eulerian method was used to simulate the underwater movement process of the high-velocity fragment.And the velocity attenuation curve of the fragment was given.The velocity attenuation, the mushrooming rule and the shock wave propagation process were studied.The penetration performance of the high-velocity fragment was obtained by considering its velocity change.When the initial velocity is 910-1 115m/s, the mushrooming is definite, which will increase the penetration resistance for the fragment sufficiently.When the initial velocity is low, the penetration distance of the underwater fragment will increase with the increasing of its initial velocity.When the initial velocity arrives at some critical value, the penetration distance will decrease as the initial velocity of the fragment increases.
2014, 34(5): 539-546.
doi: 10.11883/1001-1455(2014)05-0539-08
Abstract:
Based on ANSYS/LS＿DYNA, the multi-material fluid-solid coupling method was adopted to numerically simulate the dynamic responses of an underground straight-wall-arch tunnel to the penetration and explosion of a guided bomb GBU-28.The explosion of the guided bomb GBU-28was initiated at the critical collapse distance of the straight-wall-arch tunnel.The criterions were obtained for evaluating the dynamic stability of the surrounding rock and the dynamic strength of the lining concrete.The obtained criterions were used to analyze the simulated results and explore the interaction between the tunnel lining and the surrounding rock.When the guided bomb explodes at the critical collapse distance of the straight-wall-arch tunnel, the investigated results display the followings:(1)the surrounding rock is in the critical damage state, and the concrete lining is stable and safe; (2)the effective stress peak at the vault is obvious, and under the strip charge condition, the effective stress in the near field of the explosion is higher than that under the group charge condition; (3)the spandrel takes on a stress concentration phenomenon; (4)at the characteristic positions, the interaction pressures between the surrounding rock and the concrete lining are coupled with the vibration speeds of the particles.
Based on ANSYS/LS＿DYNA, the multi-material fluid-solid coupling method was adopted to numerically simulate the dynamic responses of an underground straight-wall-arch tunnel to the penetration and explosion of a guided bomb GBU-28.The explosion of the guided bomb GBU-28was initiated at the critical collapse distance of the straight-wall-arch tunnel.The criterions were obtained for evaluating the dynamic stability of the surrounding rock and the dynamic strength of the lining concrete.The obtained criterions were used to analyze the simulated results and explore the interaction between the tunnel lining and the surrounding rock.When the guided bomb explodes at the critical collapse distance of the straight-wall-arch tunnel, the investigated results display the followings:(1)the surrounding rock is in the critical damage state, and the concrete lining is stable and safe; (2)the effective stress peak at the vault is obvious, and under the strip charge condition, the effective stress in the near field of the explosion is higher than that under the group charge condition; (3)the spandrel takes on a stress concentration phenomenon; (4)at the characteristic positions, the interaction pressures between the surrounding rock and the concrete lining are coupled with the vibration speeds of the particles.
2014, 34(5): 547-553.
doi: 10.11883/1001-1455(2014)05-0547-07
Abstract:
Circular arc indentations were introduced into metal thin-walled cylinders.And a multi-objective optimization model was built by taking the number and the radius of the indentations as optimization parameters, as well as the specific energy absorption and the crushing force efficiency as evaluation indexes.The effects of the circular arc indentations introduced with uniform intervals were analyzed on the structural energy absorption, the maximum crushing force and the smoothness of the crushing force curve.The collision responses of different geometrical models were obtained by using the finite element software LS-DYNA.The objective functions were constructed based on the radial basis function.The multi-objective optimization for the thin-walled cylinders with the induced indentations was presented by using the ideal point method.The number and the radius of the optimal indentations were obtained.So the optimization design was achieved for the ideal indentations.
Circular arc indentations were introduced into metal thin-walled cylinders.And a multi-objective optimization model was built by taking the number and the radius of the indentations as optimization parameters, as well as the specific energy absorption and the crushing force efficiency as evaluation indexes.The effects of the circular arc indentations introduced with uniform intervals were analyzed on the structural energy absorption, the maximum crushing force and the smoothness of the crushing force curve.The collision responses of different geometrical models were obtained by using the finite element software LS-DYNA.The objective functions were constructed based on the radial basis function.The multi-objective optimization for the thin-walled cylinders with the induced indentations was presented by using the ideal point method.The number and the radius of the optimal indentations were obtained.So the optimization design was achieved for the ideal indentations.
2014, 34(5): 554-559.
doi: 10.11883/1001-1455(2014)05-0554-06
Abstract:
The deflection angle formula was derived based on the neutral axis equation with the tall chimney blasting cut section under the action of both along-wind load and across-wind resonance.Then a series of wind load cases were considered as follows:different wind Beaufort scales (grade 4-grade 6), different blasting incision angles (190°-220°) and different wind load directions (0°-180°).Their influences were achieved on the directional blasting demolition.In addition, the maximum deflection angle of the tall chimney and its existence condition were discussed.The corresponding conclusion was verified by taking the 210 mhigh chimney in Nanchang power plant as an example.The results showed that the deflection angle considering the across-wind resonance was 4-6 times as big as that considering the along-wind load.Furthermore, there existed the most unfavorable wind direction angle which would cause the maximum deflection angle under certain conditions.The maximum deflection angle would increase with the increasing wind Beaufort scale and would decrease with the decreasing blasting incision angle.
The deflection angle formula was derived based on the neutral axis equation with the tall chimney blasting cut section under the action of both along-wind load and across-wind resonance.Then a series of wind load cases were considered as follows:different wind Beaufort scales (grade 4-grade 6), different blasting incision angles (190°-220°) and different wind load directions (0°-180°).Their influences were achieved on the directional blasting demolition.In addition, the maximum deflection angle of the tall chimney and its existence condition were discussed.The corresponding conclusion was verified by taking the 210 mhigh chimney in Nanchang power plant as an example.The results showed that the deflection angle considering the across-wind resonance was 4-6 times as big as that considering the along-wind load.Furthermore, there existed the most unfavorable wind direction angle which would cause the maximum deflection angle under certain conditions.The maximum deflection angle would increase with the increasing wind Beaufort scale and would decrease with the decreasing blasting incision angle.
2014, 34(5): 560-566.
doi: 10.11883/1001-1455(2014)05-0560-07
Abstract:
To provide the key data for evaluating the launch safety of propellant charge, dynamic compression fracture experiments were carried out for the propellant charges with different original packing modes.And the corresponding compression stresses at the bottoms of the propellant beds were obtained under the same loadings.By using the discrete element method, a dynamics model was proposed to simulate the compression fracture of the propellant charges.And the simulated compression stresses were in agreement with the experimental ones.The random packing mode did not obviously affect the compression stresses at the bottoms of the propellant beds, but when the propellants were packed in the plumb mode, the compression stresses at the bottoms of the propellant beds were markedly different.
To provide the key data for evaluating the launch safety of propellant charge, dynamic compression fracture experiments were carried out for the propellant charges with different original packing modes.And the corresponding compression stresses at the bottoms of the propellant beds were obtained under the same loadings.By using the discrete element method, a dynamics model was proposed to simulate the compression fracture of the propellant charges.And the simulated compression stresses were in agreement with the experimental ones.The random packing mode did not obviously affect the compression stresses at the bottoms of the propellant beds, but when the propellants were packed in the plumb mode, the compression stresses at the bottoms of the propellant beds were markedly different.
2014, 34(5): 567-573.
doi: 10.11883/1001-1455(2014)05-0567-07
Abstract:
Aimed to an ejection life-saving system in combat aircraft with a canopy pre-damaged by miniature detonation cord, the followings were investigated as the accessibility of the ejection passageway, the damage modes of the canopy, and the impact injury degrees of the key human-body parts.The decoupled models were proposed for describing the impact of the aircrew/seat system into the canopy.In the proposed models, the two different layouts of the miniature detonation cord in the canopy were considered, i.e.Along the center of the canopy(the first layout)and around it(the second layout).Based on the above models, the process of the aircrew/seat system penetrating through the canopy was numerically simulated by using the nonlinear dynamics explicit algorithm.And the critical depths of the cutting slots were obtained for the two layouts.The simulated results indicate that the second layout is more helpful for generating an unobstructed passageway and relieving human impact injury than the first layout.
Aimed to an ejection life-saving system in combat aircraft with a canopy pre-damaged by miniature detonation cord, the followings were investigated as the accessibility of the ejection passageway, the damage modes of the canopy, and the impact injury degrees of the key human-body parts.The decoupled models were proposed for describing the impact of the aircrew/seat system into the canopy.In the proposed models, the two different layouts of the miniature detonation cord in the canopy were considered, i.e.Along the center of the canopy(the first layout)and around it(the second layout).Based on the above models, the process of the aircrew/seat system penetrating through the canopy was numerically simulated by using the nonlinear dynamics explicit algorithm.And the critical depths of the cutting slots were obtained for the two layouts.The simulated results indicate that the second layout is more helpful for generating an unobstructed passageway and relieving human impact injury than the first layout.
2014, 34(5): 574-579.
doi: 10.11883/1001-1455(2014)05-0574-06
Abstract:
According to the dispersal mixing process of explosive-driven solid powder and liquid, a transparent double-layer dispersal device was designed.A high-speed photography system was used to record the shell crushing of the dispersal device and the evolution of the solid-liquid interface and dispersal cloud status.The crack in the shell appeared and the shell fractured first along the axial direction of the shell.Before the outer shell broke, the solid-liquid interface was clear, which indicated that the solid powder and liquid mixed mainly after the shell failure.The detonation waves driven by the detonating cord presented sliding-detonation characteristics, the dispersal cloud shape took on an inverted truncated cone, and the cloud movement velocities at the different sections were inversely proportional to the axial distance of the sections from the initiation location.
According to the dispersal mixing process of explosive-driven solid powder and liquid, a transparent double-layer dispersal device was designed.A high-speed photography system was used to record the shell crushing of the dispersal device and the evolution of the solid-liquid interface and dispersal cloud status.The crack in the shell appeared and the shell fractured first along the axial direction of the shell.Before the outer shell broke, the solid-liquid interface was clear, which indicated that the solid powder and liquid mixed mainly after the shell failure.The detonation waves driven by the detonating cord presented sliding-detonation characteristics, the dispersal cloud shape took on an inverted truncated cone, and the cloud movement velocities at the different sections were inversely proportional to the axial distance of the sections from the initiation location.
2014, 34(5): 580-585.
doi: 10.11883/1001-1455(2014)05-0580-06
Abstract:
Hydrogen constant volume combustion was investigated by using a constant volume combustion bomb and a high－speed data acquisition system.The pressure change in the hydrogen constant volume combustion bomb was summarized and the rules of the combustion－explosion pressure and the explosion constant were generalized.The combustion pressure changing in the constant volume bomb with central ignition can be described in the following process.The combustion which was interfered by ignition was at a constant pressure, the pressure increased slowly at first, and then increased rapidly during the combustion.There would be a pressure oscillation in the later half stage of the combustion.If it was not under the extreme conditions, the explosion peak pressure increased firstly and then decreased with the fuel equivalence ratio increasing.There was almost a linear relation between the initial pressure and the peak pressure.The explosion pressure and peak pressure decreased with the initial temperature increasing.The explosion constant increased firstly and then decreased with the fuel equivalence ratio increasing, too.When the fuel equivalence ratio was lower than 4, the explosion constant increased with the initial pressure increasing, or vice versa.When the fuel equivalence ratio was lower than 2.5, the explosion constant decreased with the temperature increasing.And when the fuel equivalence ratio was higher than 2.5, it was just the opposite.
Hydrogen constant volume combustion was investigated by using a constant volume combustion bomb and a high－speed data acquisition system.The pressure change in the hydrogen constant volume combustion bomb was summarized and the rules of the combustion－explosion pressure and the explosion constant were generalized.The combustion pressure changing in the constant volume bomb with central ignition can be described in the following process.The combustion which was interfered by ignition was at a constant pressure, the pressure increased slowly at first, and then increased rapidly during the combustion.There would be a pressure oscillation in the later half stage of the combustion.If it was not under the extreme conditions, the explosion peak pressure increased firstly and then decreased with the fuel equivalence ratio increasing.There was almost a linear relation between the initial pressure and the peak pressure.The explosion pressure and peak pressure decreased with the initial temperature increasing.The explosion constant increased firstly and then decreased with the fuel equivalence ratio increasing, too.When the fuel equivalence ratio was lower than 4, the explosion constant increased with the initial pressure increasing, or vice versa.When the fuel equivalence ratio was lower than 2.5, the explosion constant decreased with the temperature increasing.And when the fuel equivalence ratio was higher than 2.5, it was just the opposite.
2014, 34(5): 586-593.
doi: 10.11883/1001-1455(2014)05-0586-08
Abstract:
Two kinds of different volatile pulverized coal were tested in a semi-enclosed vertical combustion tube.And a high-speed video camera and an infrared imager were used to record the flame propagation process and the spatial flame temperature distribution, respectively.The changes of the flame propagation velocity and temperature with time were analyzed for the two different coal dust clouds during combustion.Experimental results show that the flame propagation velocity and flame temperature of the high-volatile coal dust cloud are higher than those of the low-volatile coal dust cloud under the same experimental conditions.And the volumic mass of coal dust cloud as well as ignition energy can affect the flame propagation.With increasing the volumic mass of coal dust cloud, the flame propagation velocity and the flame temperature increase at first and then decrease, oscillating phenomena appear in the next process.With increasing the ignition energy, the flame propagation velocity and flame temperature increase.Based on the experimental data, an empirical formula was proposed for calculating the flame propagation velocity and flame temperature under certain conditions.
Two kinds of different volatile pulverized coal were tested in a semi-enclosed vertical combustion tube.And a high-speed video camera and an infrared imager were used to record the flame propagation process and the spatial flame temperature distribution, respectively.The changes of the flame propagation velocity and temperature with time were analyzed for the two different coal dust clouds during combustion.Experimental results show that the flame propagation velocity and flame temperature of the high-volatile coal dust cloud are higher than those of the low-volatile coal dust cloud under the same experimental conditions.And the volumic mass of coal dust cloud as well as ignition energy can affect the flame propagation.With increasing the volumic mass of coal dust cloud, the flame propagation velocity and the flame temperature increase at first and then decrease, oscillating phenomena appear in the next process.With increasing the ignition energy, the flame propagation velocity and flame temperature increase.Based on the experimental data, an empirical formula was proposed for calculating the flame propagation velocity and flame temperature under certain conditions.
2014, 34(5): 594-600.
doi: 10.11883/1001-1455(2014)05-0594-07
Abstract:
The AUTODYN code was applied to investigate the performance changes of the ceramic/metal armors under ballistic impact with the different geometrical parameters.A two-dimensional axisymmetric SPH-Lagrange model was developed, and it was validated by the experimental results.By using the SPH-Lagrange model, numerical simulations were carried out for the impact of the alumina ceramic/aluminum armors by the cylindrical tungsten projectiles in the cases of the different geometrical parameters.Based on the simulation results, the armor ballistic limit velocities of the armors were discussed considering the thicknesses and planar sizes of the armor plates as well as the lengths and diameters of the projectiles.Dimensional analysis was performed to achieve a dimensionless formula for describing the armor ballistic limit velocity varied with the geometrical parameters.And the corresponding empirical formula was given on the basis of the numerical data.
The AUTODYN code was applied to investigate the performance changes of the ceramic/metal armors under ballistic impact with the different geometrical parameters.A two-dimensional axisymmetric SPH-Lagrange model was developed, and it was validated by the experimental results.By using the SPH-Lagrange model, numerical simulations were carried out for the impact of the alumina ceramic/aluminum armors by the cylindrical tungsten projectiles in the cases of the different geometrical parameters.Based on the simulation results, the armor ballistic limit velocities of the armors were discussed considering the thicknesses and planar sizes of the armor plates as well as the lengths and diameters of the projectiles.Dimensional analysis was performed to achieve a dimensionless formula for describing the armor ballistic limit velocity varied with the geometrical parameters.And the corresponding empirical formula was given on the basis of the numerical data.
2014, 34(5): 601-607.
doi: 10.11883/1001-1455(2014)05-0601-07
Abstract:
The three-dimensional Voronoi technique and the explicit finite element method were utilized to investigate the micro-inertia effect and dynamic plastic Poisson's ratio of closed-cell and opencell metallic foams.The simulation results indicate that the plastic Poisson's ratio decrease with increasing nominal strain, the peak value of which decreases as the impact velocity increases.And the Poisson's ratio increases with the increasing of relative density.The micro-inertia plays little role in enhancing the plateau stress of metallic foams.The above simulation results can explain the existent experimental phenomenon that the crushing stress decreases with increasing loading rates, which is endured by the closed-cell aluminum foam under lateral constraint.
The three-dimensional Voronoi technique and the explicit finite element method were utilized to investigate the micro-inertia effect and dynamic plastic Poisson's ratio of closed-cell and opencell metallic foams.The simulation results indicate that the plastic Poisson's ratio decrease with increasing nominal strain, the peak value of which decreases as the impact velocity increases.And the Poisson's ratio increases with the increasing of relative density.The micro-inertia plays little role in enhancing the plateau stress of metallic foams.The above simulation results can explain the existent experimental phenomenon that the crushing stress decreases with increasing loading rates, which is endured by the closed-cell aluminum foam under lateral constraint.
2014, 34(5): 608-614.
doi: 10.11883/1001-1455(2014)05-0608-07
Abstract:
To research the wounding effects of small caliber rifle cartridges, the following cartridges were chosen as the investigated objectives:the 5.56×45 mm NATO, 5.45×39 mm and 5.8×42 mm DBP 87 rifle cartridges.A series of theoretical analyses were performed for the above cartridges on their structural characteristics, performance parameters and motion in gelatin.The corresponding experiments were carried out for the cartridges penetrating into gelatin targets and the experimental results were discussed.The wounding effect of the 5.8×42 mm DBP 87 rifle cartridge was the best among the three kinds of small caliber rifle cartridges, which was consistent with the theoretical analyses.
To research the wounding effects of small caliber rifle cartridges, the following cartridges were chosen as the investigated objectives:the 5.56×45 mm NATO, 5.45×39 mm and 5.8×42 mm DBP 87 rifle cartridges.A series of theoretical analyses were performed for the above cartridges on their structural characteristics, performance parameters and motion in gelatin.The corresponding experiments were carried out for the cartridges penetrating into gelatin targets and the experimental results were discussed.The wounding effect of the 5.8×42 mm DBP 87 rifle cartridge was the best among the three kinds of small caliber rifle cartridges, which was consistent with the theoretical analyses.
2014, 34(5): 615-621.
doi: 10.11883/1001-1455(2014)05-0615-07
Abstract:
The study explored how to keep the reinforced concrete containment sealed and undamaged for the nuclear power plant subjected to a severe earthquake during the plant life.The propagation of seismic waves along the structure was analyzed.And based on the structural isolation technology, a three-dimensional finite element model was developed for the reinforced concrete containment.The application of the isolation technology to the reinforced concrete containment was discussed by applying a deterministic methodological approach.For the nuclear power plant subjected to a safe shutdown earthquake, the dynamic response of the reinforced concrete containment with isolators was compared with that of one without isolators.The accelerations at the dome vertex of the isolated containment along the x, yand z axes are about 2.85m/s2, 3.05m/s2 and 12.84m/s2, respectively, which are 79.52%, 79.47%and 27.56%, respectively, lower compared with the isolated containment.So the isolation system is helpful for mitigating the seismic response of the nuclear power plant containment.
The study explored how to keep the reinforced concrete containment sealed and undamaged for the nuclear power plant subjected to a severe earthquake during the plant life.The propagation of seismic waves along the structure was analyzed.And based on the structural isolation technology, a three-dimensional finite element model was developed for the reinforced concrete containment.The application of the isolation technology to the reinforced concrete containment was discussed by applying a deterministic methodological approach.For the nuclear power plant subjected to a safe shutdown earthquake, the dynamic response of the reinforced concrete containment with isolators was compared with that of one without isolators.The accelerations at the dome vertex of the isolated containment along the x, yand z axes are about 2.85m/s2, 3.05m/s2 and 12.84m/s2, respectively, which are 79.52%, 79.47%and 27.56%, respectively, lower compared with the isolated containment.So the isolation system is helpful for mitigating the seismic response of the nuclear power plant containment.
2014, 34(5): 622-629.
doi: 10.11883/1001-1455(2014)05-0622-08
Abstract:
Based on the Archard's theory, a mass abrasion model for the projectile was proposed by using the multi-scale method of analyzing from the microscopic plastic deformation to the macroscopic mass loss of the projectile.In combination of the dynamic spherical cavity-expansion theory of the concrete materials and the abrasion model, the receding displacement of the point on the projectile surface was obtained.Thereby, the calculation results such as the shape of the projectile, the depth of penetration, the mass loss of the projectile, and so on, are consistent with the experimental results.Results show that the mass loss of the projectile has a great influence on the time and depth of the penetration with increasing impact velocity in the penetration process.The overload encountered by the projectile during the penetration is different from that of the rigid one.Improving the yield strength of the projectile can effectively reduce its mass loss and increase its depth of penetration.
Based on the Archard's theory, a mass abrasion model for the projectile was proposed by using the multi-scale method of analyzing from the microscopic plastic deformation to the macroscopic mass loss of the projectile.In combination of the dynamic spherical cavity-expansion theory of the concrete materials and the abrasion model, the receding displacement of the point on the projectile surface was obtained.Thereby, the calculation results such as the shape of the projectile, the depth of penetration, the mass loss of the projectile, and so on, are consistent with the experimental results.Results show that the mass loss of the projectile has a great influence on the time and depth of the penetration with increasing impact velocity in the penetration process.The overload encountered by the projectile during the penetration is different from that of the rigid one.Improving the yield strength of the projectile can effectively reduce its mass loss and increase its depth of penetration.
2014, 34(5): 630-635.
doi: 10.11883/1001-1455(2014)05-0630-06
Abstract:
Penetration experiments were conducted to explore an expression formula for the stress endured by the nose of the projectile during cratering.To obtain the relation between penetration velocity and penetration depth, the relation between penetration depth and time was recorded by using a high-speed camera.And the least square method was used to analyze the relation of the kinetic energy consumed by the projectile with the penetration depth at the end of cratering.Thereby, an expression formula was proposed for the stress endured by the nose of the projectile during cratering.The calculation results display that the proposed stress formula can describe the relation between the penetration velocity and the crater depth under high-velocity impact.
Penetration experiments were conducted to explore an expression formula for the stress endured by the nose of the projectile during cratering.To obtain the relation between penetration velocity and penetration depth, the relation between penetration depth and time was recorded by using a high-speed camera.And the least square method was used to analyze the relation of the kinetic energy consumed by the projectile with the penetration depth at the end of cratering.Thereby, an expression formula was proposed for the stress endured by the nose of the projectile during cratering.The calculation results display that the proposed stress formula can describe the relation between the penetration velocity and the crater depth under high-velocity impact.
2014, 34(5): 636-640.
doi: 10.11883/1001-1455(2014)05-0636-05
Abstract:
The copper cylinder tests were carried out to explore the effects of the aluminum contents on the performances of aluminized RDX-based explosives.In the tests, the outer diameter of the copper cylinder was 50 mm and the mass fractions of aluminum in the three RDX-based explosives were 0, 15% and 30%, respectively.In the three explosives tested, the acceleration ability of the explosive with the aluminum mass fraction of 15% was highest.However, the acceleration ability of the explosive with the aluminum mass fraction of 30% was lower than that of the pure RDX.The Gurney formula was used to analyze the reaction process of aluminum with detonation products in the aluminized RDX-based explosives.About 49% aluminum by mass had reacted in the explosive with the aluminum mass fraction of 15% at 34 μs, while in the explosive with the aluminum mass fraction of 30%, only about 21% aluminum by mass had reacted.And the reaction time of aluminum powder with the size of 10 μm was 50-200 μs.
The copper cylinder tests were carried out to explore the effects of the aluminum contents on the performances of aluminized RDX-based explosives.In the tests, the outer diameter of the copper cylinder was 50 mm and the mass fractions of aluminum in the three RDX-based explosives were 0, 15% and 30%, respectively.In the three explosives tested, the acceleration ability of the explosive with the aluminum mass fraction of 15% was highest.However, the acceleration ability of the explosive with the aluminum mass fraction of 30% was lower than that of the pure RDX.The Gurney formula was used to analyze the reaction process of aluminum with detonation products in the aluminized RDX-based explosives.About 49% aluminum by mass had reacted in the explosive with the aluminum mass fraction of 15% at 34 μs, while in the explosive with the aluminum mass fraction of 30%, only about 21% aluminum by mass had reacted.And the reaction time of aluminum powder with the size of 10 μm was 50-200 μs.
