2018 Vol. 38, No. 5
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2018, 38(5): 937-947.
doi: 10.11883/bzycj-2017-0329
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In order to study the propagating characteristics of rotating detonation waves in the plane-radial structure, experiments were carried out in a plane-radial rotating detonation engine (RDE) with a variable reactants mass flow rate and equivalence ratio. Results indicate that detonation waves initiate successfully and propagate continuously on the plane-radial RDE, leading to two kinds of propagation modes:single-wave and two-wave propagation mode. The interaction between the plenum chamber and the combustor occurs in the operating process. When the mass flow rate is less than 159.20 g/s, rotating detonation waves propagate in the single-wave mode. The propagation frequency varies from 4.56 kHz to 4.62 kHz. The pressure peak and the velocity of detonation waves increase with the decreasing distance from the outer circle. In the case of the mass flow rate larger than 186.89 g/s, detonation waves propagate in the two-wave mode and the frequency varies from 8.59 kHz to 8.64 kHz. The two-wave propagation mode undergoes four stages:the single-wave stage at the initiation, the stable two-wave stage, the unstable two-wave stage, and finally the single-wave propagation stage in the exhausting stage. When the mass flow rate varies from 159.20 g/s to 186.89 g/s, rotating detonation waves propagate in the single/two-wave mixed mode. When the equivalence ratio is close to the stoichiometric ratio, the propagation process of detonation waves is more stable. In contrast, the detonation wave propagation is unstable and there is a failing initiation at the beginning or an interruption in the propagation process when the equivalence ratio is deviated from the stoichiometric ratio.
In order to study the propagating characteristics of rotating detonation waves in the plane-radial structure, experiments were carried out in a plane-radial rotating detonation engine (RDE) with a variable reactants mass flow rate and equivalence ratio. Results indicate that detonation waves initiate successfully and propagate continuously on the plane-radial RDE, leading to two kinds of propagation modes:single-wave and two-wave propagation mode. The interaction between the plenum chamber and the combustor occurs in the operating process. When the mass flow rate is less than 159.20 g/s, rotating detonation waves propagate in the single-wave mode. The propagation frequency varies from 4.56 kHz to 4.62 kHz. The pressure peak and the velocity of detonation waves increase with the decreasing distance from the outer circle. In the case of the mass flow rate larger than 186.89 g/s, detonation waves propagate in the two-wave mode and the frequency varies from 8.59 kHz to 8.64 kHz. The two-wave propagation mode undergoes four stages:the single-wave stage at the initiation, the stable two-wave stage, the unstable two-wave stage, and finally the single-wave propagation stage in the exhausting stage. When the mass flow rate varies from 159.20 g/s to 186.89 g/s, rotating detonation waves propagate in the single/two-wave mixed mode. When the equivalence ratio is close to the stoichiometric ratio, the propagation process of detonation waves is more stable. In contrast, the detonation wave propagation is unstable and there is a failing initiation at the beginning or an interruption in the propagation process when the equivalence ratio is deviated from the stoichiometric ratio.
2018, 38(5): 948-956.
doi: 10.11883/bzycj-2017-0328
Abstract:
The smoothed particle hydrodynamics (SPH) method is widely used in debris cloud simulation under hypervelocity impact. The SPH solver in AUTODYN was employed to investigate the effects of the no-failure model, the Grady failure model and the maximum tension failure model on the simulation results of debris cloud. When using the no-failure model, the simulation result and material response were not consistent with the experiment. Compared with the Grady model, the material under the maximum tension model was more difficult to fail, which would slightly weaken the expansion of debris cloud, produce less but heavier debris because of particles gathering, and thus improve the penetration performance of debris cloud. Similarly, by increasing the failure stress threshold, the above result was also obtained. Considering the material response and debris distribution, the simulation result by the Grady model was closer to the experiment. However, the difference between the Grady model and the maximum tension model was related to the impact condition, and more complete fragmentation of the material would lead to a smaller difference.
The smoothed particle hydrodynamics (SPH) method is widely used in debris cloud simulation under hypervelocity impact. The SPH solver in AUTODYN was employed to investigate the effects of the no-failure model, the Grady failure model and the maximum tension failure model on the simulation results of debris cloud. When using the no-failure model, the simulation result and material response were not consistent with the experiment. Compared with the Grady model, the material under the maximum tension model was more difficult to fail, which would slightly weaken the expansion of debris cloud, produce less but heavier debris because of particles gathering, and thus improve the penetration performance of debris cloud. Similarly, by increasing the failure stress threshold, the above result was also obtained. Considering the material response and debris distribution, the simulation result by the Grady model was closer to the experiment. However, the difference between the Grady model and the maximum tension model was related to the impact condition, and more complete fragmentation of the material would lead to a smaller difference.
2018, 38(5): 957-965.
doi: 10.11883/bzycj-2017-0075
Abstract:
Impact-induced initiation criteria of Al particles reinforced PTFE (PTFE/Al) prepared by compression/sintering were studied by split Hopkinson pressure bar (SHPB) and high speed photography in this work. SHPB systems comprising of either steel or aluminum bars were applied to test PTFE/Al samples of different dimensions, in order to study the effect of the impact stress and the loading strain rate on the impact-induced initiation behaviors of PTFE/Al. It shows that the impact-induced initiation process of PTFE/Al mainly includes the deformation, fragmentation and reaction, which is simultaneously related to the impact stress and the loading strain rate. Based on the experimental results, the criteria of impact stress and loading strain rate for the impact-induced initiation of PTFE/Al have been obtained. Moreover, an analytical expression of impact-induced initiation criteria including impact stress and loading strain rate was established and a theoretical curve was predicted for the impact-induced initiation events of PTFE/Al under SHPB tests.
Impact-induced initiation criteria of Al particles reinforced PTFE (PTFE/Al) prepared by compression/sintering were studied by split Hopkinson pressure bar (SHPB) and high speed photography in this work. SHPB systems comprising of either steel or aluminum bars were applied to test PTFE/Al samples of different dimensions, in order to study the effect of the impact stress and the loading strain rate on the impact-induced initiation behaviors of PTFE/Al. It shows that the impact-induced initiation process of PTFE/Al mainly includes the deformation, fragmentation and reaction, which is simultaneously related to the impact stress and the loading strain rate. Based on the experimental results, the criteria of impact stress and loading strain rate for the impact-induced initiation of PTFE/Al have been obtained. Moreover, an analytical expression of impact-induced initiation criteria including impact stress and loading strain rate was established and a theoretical curve was predicted for the impact-induced initiation events of PTFE/Al under SHPB tests.
2018, 38(5): 966-976.
doi: 10.11883/bzycj-2017-0090
Abstract:
In order to investigate the damage modes and failure mechanism of the concrete dome of the liquefied natural gas (LNG) storage tank subjected to impact by a rigid circular cylinder, the finite element (FE) model of the outer concrete tank of the 160 000 m3 LNG storage tank for an actual LNG project and a cylindrical impactor is established based on ANSYS/LS-DYNAFE analysis software platform. The accuracy of the numerical simulation method and the material model employed has been verified by simulating the impact perforation of reinforced concrete slabs subjected to projectile with high speed. The dynamic response of structures under impacting with variable speed, angle, location, and diameter are studied. Based on the dynamic response of the outer concrete tank of the LNG storage tank subjected to impact loading, three damage modes are defined and the failure mechanism of each mode is revealed from the point view of energy. The response characteristics and rules with the change of the impact parameters are obtained. The results show that the impact angle and the diameter of the impactor affect significantly on the failure modes of dome, and the impact position at the dome has a negligible effect on the failure modes.
In order to investigate the damage modes and failure mechanism of the concrete dome of the liquefied natural gas (LNG) storage tank subjected to impact by a rigid circular cylinder, the finite element (FE) model of the outer concrete tank of the 160 000 m3 LNG storage tank for an actual LNG project and a cylindrical impactor is established based on ANSYS/LS-DYNAFE analysis software platform. The accuracy of the numerical simulation method and the material model employed has been verified by simulating the impact perforation of reinforced concrete slabs subjected to projectile with high speed. The dynamic response of structures under impacting with variable speed, angle, location, and diameter are studied. Based on the dynamic response of the outer concrete tank of the LNG storage tank subjected to impact loading, three damage modes are defined and the failure mechanism of each mode is revealed from the point view of energy. The response characteristics and rules with the change of the impact parameters are obtained. The results show that the impact angle and the diameter of the impactor affect significantly on the failure modes of dome, and the impact position at the dome has a negligible effect on the failure modes.
2018, 38(5): 977-984.
doi: 10.11883/bzycj-2017-0013
Abstract:
In order to accurately and efficiently simulate the blasting demolition project, a simplified constitutive model of reinforced concrete has been proposed by using the method of combination modulus, based on the concrete damage plasticity model in LS-DYNA. In the model, we have taken the tension stiffening effect, the ratio of reinforcement effect on tension stiffening, and the confinement effect of stirrups of reinforced concrete into account. On the basis of experimental verification, the numerical calculation has been performed to simulate the delay blasting demolition of a double incision reinforced concrete chimney. The simulated results show that the proposed model can qualitatively reproduce the collapse and movement processes of chimney.
In order to accurately and efficiently simulate the blasting demolition project, a simplified constitutive model of reinforced concrete has been proposed by using the method of combination modulus, based on the concrete damage plasticity model in LS-DYNA. In the model, we have taken the tension stiffening effect, the ratio of reinforcement effect on tension stiffening, and the confinement effect of stirrups of reinforced concrete into account. On the basis of experimental verification, the numerical calculation has been performed to simulate the delay blasting demolition of a double incision reinforced concrete chimney. The simulated results show that the proposed model can qualitatively reproduce the collapse and movement processes of chimney.
2018, 38(5): 985-992.
doi: 10.11883/bzycj-2017-0029
Abstract:
The full moment tensor inversion is an important tool to monitor underground nuclear tests, thus has been employed in this paper to analyze the recorded data of seven underground nuclear tests and three natural earthquakes in the region of Eastern Kazakhstan. The results show that, except the obvious explosion source in underground nuclear tests, the components of double couple (DC) and compensate linear vector dipole (CLVD) also exist, in which the later plays a more important role and could be explained by the explosion-induced spall. In the case of natural earthquakes, the DC component is the main contribution, in consistent with the model of shear dislocation seismic source.
The full moment tensor inversion is an important tool to monitor underground nuclear tests, thus has been employed in this paper to analyze the recorded data of seven underground nuclear tests and three natural earthquakes in the region of Eastern Kazakhstan. The results show that, except the obvious explosion source in underground nuclear tests, the components of double couple (DC) and compensate linear vector dipole (CLVD) also exist, in which the later plays a more important role and could be explained by the explosion-induced spall. In the case of natural earthquakes, the DC component is the main contribution, in consistent with the model of shear dislocation seismic source.
2018, 38(5): 993-998.
doi: 10.11883/bzycj-2016-0003
Abstract:
Aluminum dust explosion experiments have been carried out in the rectangular pipe dust explosion device to study on the effects of the ignition delay time, the dust particle size, and the dust concentration on the maximum explosion pressure as well as the maximum rise rate of explosion pressure. Experimental results show that all three parameters affect significantly the explosive pressure of aluminum dust. The maximum explosion pressure and the maximum explosion pressure first increase and then decrease with the increasing ignition delay time or the decreasing size of the aluminum powder. The rising rates of both the maximum explosive pressure and the maximum explosion pressure increase and then decrease as the aluminum concentration increases, indicating that a certain concentration exists which could lead to the largest explosive power.
Aluminum dust explosion experiments have been carried out in the rectangular pipe dust explosion device to study on the effects of the ignition delay time, the dust particle size, and the dust concentration on the maximum explosion pressure as well as the maximum rise rate of explosion pressure. Experimental results show that all three parameters affect significantly the explosive pressure of aluminum dust. The maximum explosion pressure and the maximum explosion pressure first increase and then decrease with the increasing ignition delay time or the decreasing size of the aluminum powder. The rising rates of both the maximum explosive pressure and the maximum explosion pressure increase and then decrease as the aluminum concentration increases, indicating that a certain concentration exists which could lead to the largest explosive power.
2018, 38(5): 999-1005.
doi: 10.11883/bzycj-2016-0052
Abstract:
In order to simulate the implosive compression process of a multilayer coiled solenoid and its associated interfacial instability by using the smooth particle hydrodynamics (SPH) solver, the AUTODYN user-defined subroutines have been employed to build a three dimensional solenoid model and achieve periodic boundary conditions. The simulated results show that the perturbation of the solenoid structure in the implosive compression process grows fast and then the interface becomes unstable at the end of compression, in agreement with the experimental results. The parameters of the solenoid structure significantly affect the development of the interfacial instability. The smaller the spiral angle, the larger the interfacial instability at the end of compression process, one the other hand, the smaller the wire diameter, the weaker the interfacial instability at the end of compression process.
In order to simulate the implosive compression process of a multilayer coiled solenoid and its associated interfacial instability by using the smooth particle hydrodynamics (SPH) solver, the AUTODYN user-defined subroutines have been employed to build a three dimensional solenoid model and achieve periodic boundary conditions. The simulated results show that the perturbation of the solenoid structure in the implosive compression process grows fast and then the interface becomes unstable at the end of compression, in agreement with the experimental results. The parameters of the solenoid structure significantly affect the development of the interfacial instability. The smaller the spiral angle, the larger the interfacial instability at the end of compression process, one the other hand, the smaller the wire diameter, the weaker the interfacial instability at the end of compression process.
2018, 38(5): 1006-1012.
doi: 10.11883/bzycj-2016-0194
Abstract:
Based on a large number of measured vibration signals of deep hole bench blasting in near field, this paper has contributed the trend mainly to the nonlinear distortion and the low frequency interference superposition with a large amplitude pulse input. On this basis, the effective monitoring range of test instruments has been chosen as criteria to identify the part of the trend. Using ensemble empirical mode decomposition (EEMD), the wavelet analysis, and other signal analysis methods, a trend elimination method is proposed here, which is based on the combination of the frequency band distribution of each intrinsic mode function component and artificial identification. In addition, a wavelet threshold denoising method is also proposed based on autocorrelation analysis to identify noise characteristics. Examples show that the methods are effective and can be realized by batch pretreatment of blasting signals.
Based on a large number of measured vibration signals of deep hole bench blasting in near field, this paper has contributed the trend mainly to the nonlinear distortion and the low frequency interference superposition with a large amplitude pulse input. On this basis, the effective monitoring range of test instruments has been chosen as criteria to identify the part of the trend. Using ensemble empirical mode decomposition (EEMD), the wavelet analysis, and other signal analysis methods, a trend elimination method is proposed here, which is based on the combination of the frequency band distribution of each intrinsic mode function component and artificial identification. In addition, a wavelet threshold denoising method is also proposed based on autocorrelation analysis to identify noise characteristics. Examples show that the methods are effective and can be realized by batch pretreatment of blasting signals.
2018, 38(5): 1013-1022.
doi: 10.11883/bzycj-2017-0039
Abstract:
The throttling ring is the key component of a gun recoil brake, erosion wear is the main reason for the failure of the throttling ring. In order to improve the erosive resistance ability and the inherent reliability of throttling ring, with the help of material surface strengthening technology, the wear-resistant alloy coatings on the inner diameter surface of throttling ring were prepared by micro arc deposition and laser cladding coating technology, Cu-based alloy and Ni-based alloy were selected to prepare wear-resistant coatings. Through the microstructure observation, micro hardness test and coating quality comparison of four kinds of wear-resistant coatings, two kinds of coatings were eliminated. In order to test the erosive resistance, the improvd throttling rings were installed on the recoil brake. Erosion wear tests were carried out by recoil mechanism test bench. Wear morphology and wear weight loss of improvement parts are compared under the same conditions. Finally, according to the comprehensive analysis of microstructure, microhardness, energy spectrum and erosion wear test results of wear resistant coatings, it is concluded that the Ni-based alloy coating by laser cladding technology shows the best performance in the above four types of coatings, indicating it is an effective means to improve erosive resistance of the throttling ring.
The throttling ring is the key component of a gun recoil brake, erosion wear is the main reason for the failure of the throttling ring. In order to improve the erosive resistance ability and the inherent reliability of throttling ring, with the help of material surface strengthening technology, the wear-resistant alloy coatings on the inner diameter surface of throttling ring were prepared by micro arc deposition and laser cladding coating technology, Cu-based alloy and Ni-based alloy were selected to prepare wear-resistant coatings. Through the microstructure observation, micro hardness test and coating quality comparison of four kinds of wear-resistant coatings, two kinds of coatings were eliminated. In order to test the erosive resistance, the improvd throttling rings were installed on the recoil brake. Erosion wear tests were carried out by recoil mechanism test bench. Wear morphology and wear weight loss of improvement parts are compared under the same conditions. Finally, according to the comprehensive analysis of microstructure, microhardness, energy spectrum and erosion wear test results of wear resistant coatings, it is concluded that the Ni-based alloy coating by laser cladding technology shows the best performance in the above four types of coatings, indicating it is an effective means to improve erosive resistance of the throttling ring.
2018, 38(5): 1023-1030.
doi: 10.11883/bzycj-2017-0043
Abstract:
In the present paper, based on the compressible elastic-plastic response penetration model of plain concrete proposed by Forrestal, a dynamic spherical cavity-expansion penetration model for reinforced concrete targets is constructed with considering the hoop confinement effect derived from reinforcing bars in the crushed region. The theoretical solution of radial stress for the compressible reinforced concrete is achieved through introducing the reinforcement ratio, i.e., the volume fraction of rebars in the concrete target. The effects of reinforcement ratio on radial stress and size of response regions are discussed. The results show that the hoop confinement effect derived from reinforcing bars changes the size of each region and improves the radial stress at cavity surface.
In the present paper, based on the compressible elastic-plastic response penetration model of plain concrete proposed by Forrestal, a dynamic spherical cavity-expansion penetration model for reinforced concrete targets is constructed with considering the hoop confinement effect derived from reinforcing bars in the crushed region. The theoretical solution of radial stress for the compressible reinforced concrete is achieved through introducing the reinforcement ratio, i.e., the volume fraction of rebars in the concrete target. The effects of reinforcement ratio on radial stress and size of response regions are discussed. The results show that the hoop confinement effect derived from reinforcing bars changes the size of each region and improves the radial stress at cavity surface.
2018, 38(5): 1031-1038.
doi: 10.11883/bzycj-2017-0049
Abstract:
In a 12 m long seamless stainless steel pipe, the influence of ignition energy on the propagation characteristics of propane air mixture in the closed tube and the influence of shock wave on the dynamic loading of the pipe wall are investigated. The results indicate that the dynamic initial ignition energy has a significant impact on explosion flame propagation and wall response of premixed gas. The greater the ignition energy, the greater explosion intensity, explosion pressure peak pressure and maximum wall strain is. And the pressure wave and wall strain development are in good agreement. In the process of flame propagation, the flame will briefly extinguished and happen again by reflection effect from the end of the pipeline. The strain signal is mainly distributed in the frequency range of 0-781.25 Hz and the maximum strain rate of the pipe wall subjected to shock wave loading exceeds 10-3 s-1. So the pipe wall strain belongs to the dynamic response in the experiment.
In a 12 m long seamless stainless steel pipe, the influence of ignition energy on the propagation characteristics of propane air mixture in the closed tube and the influence of shock wave on the dynamic loading of the pipe wall are investigated. The results indicate that the dynamic initial ignition energy has a significant impact on explosion flame propagation and wall response of premixed gas. The greater the ignition energy, the greater explosion intensity, explosion pressure peak pressure and maximum wall strain is. And the pressure wave and wall strain development are in good agreement. In the process of flame propagation, the flame will briefly extinguished and happen again by reflection effect from the end of the pipeline. The strain signal is mainly distributed in the frequency range of 0-781.25 Hz and the maximum strain rate of the pipe wall subjected to shock wave loading exceeds 10-3 s-1. So the pipe wall strain belongs to the dynamic response in the experiment.
2018, 38(5): 1039-1044.
doi: 10.11883/bzycj-2017-0055
Abstract:
In order to understand the spallation of a target subjected to the impact load of an explosively formed projectile (EFP), on the basis of wave mechanics and basic assumptions, a mechanical model was developed to describe the spallation of the finite-thickness target vertically penetrated by an EFP. By the developed model, the spallation process of the target plate was obtained, and its formula was derived. The result shows as following. When the impact velocity of the EFP is 1 800 m/s and the thickness of the target increases from 35 mm to 60 mm, the thickness of the falcate spallation zone at the back of the target increases and its length decreases. When the thickness of the target is 40 mm and the impact velocity increases from 1 600 m/s to 1 900 m/s, the thickness of the falcate spallation zone at the back of the target decreases and its length increases. Dynamic tests were carried out on the EFPs penetration into the rolled homogeneous armor targets with the thickness of 40 mm. The experimental result is in good agreement with the theoretical prediction.
In order to understand the spallation of a target subjected to the impact load of an explosively formed projectile (EFP), on the basis of wave mechanics and basic assumptions, a mechanical model was developed to describe the spallation of the finite-thickness target vertically penetrated by an EFP. By the developed model, the spallation process of the target plate was obtained, and its formula was derived. The result shows as following. When the impact velocity of the EFP is 1 800 m/s and the thickness of the target increases from 35 mm to 60 mm, the thickness of the falcate spallation zone at the back of the target increases and its length decreases. When the thickness of the target is 40 mm and the impact velocity increases from 1 600 m/s to 1 900 m/s, the thickness of the falcate spallation zone at the back of the target decreases and its length increases. Dynamic tests were carried out on the EFPs penetration into the rolled homogeneous armor targets with the thickness of 40 mm. The experimental result is in good agreement with the theoretical prediction.
2018, 38(5): 1045-1050.
doi: 10.11883/bzycj-2017-0056
Abstract:
Quasi-static pressure is important for the design of explosion containment vessels. Experiments of the spherical vessel under blast loading, in which the quasi-static pressure was measured by the pressure sensors of two different installations, i.e. flush installation and guide-hole installation, were carried out. The data obtained by the pressure sensors are consistent with each other. Based on the formula form derived theoretically, the empirical formula was obtained by fitting the data. The main results are as follows:(1) the pressure in the vessel goes into quasi-static state after the blast wave reflects back and forth three times in the vessel; (2) the quasi-static pressure in the spherical vessel is proportional to the explosion equivalent-to-vessel volume ratio, and the empirical coefficient is 1.10 MPa·m3/kg TNT.
Quasi-static pressure is important for the design of explosion containment vessels. Experiments of the spherical vessel under blast loading, in which the quasi-static pressure was measured by the pressure sensors of two different installations, i.e. flush installation and guide-hole installation, were carried out. The data obtained by the pressure sensors are consistent with each other. Based on the formula form derived theoretically, the empirical formula was obtained by fitting the data. The main results are as follows:(1) the pressure in the vessel goes into quasi-static state after the blast wave reflects back and forth three times in the vessel; (2) the quasi-static pressure in the spherical vessel is proportional to the explosion equivalent-to-vessel volume ratio, and the empirical coefficient is 1.10 MPa·m3/kg TNT.
2018, 38(5): 1051-1056.
doi: 10.11883/bzycj-2017-0057
Abstract:
In order to understand the fracture law of rock by shock wave in deep water, an electric pulse fracturing device with hydrostatic pressure up to 35 MPa was established, which can simulate the confining pressure of 3 000 m underground. The experiments of plasma impact fracturing under different hydrostatic pressures were carried out. The maximum operating parameter of the fracturing device is 20 kV/40 kJ. Six sandstones were fractured by electric pulse under the hydrostatic pressure which ranges from 0 to 25 MPa. The experimental results show that the length and width of fracture decrease significantly with the increase of hydrostatic pressure under the same energy. So the destroy range of shock wave decreases and the porosity and permeability decline with the increase of confining pressure. The hydrostatic pressure has obvious influence on the formation, distribution and growth of the crack after impact fracture. Compared with the cracks formed by atmospheric pressure, cracks are concentrated in the electrode. The number of cracks is more but the length is shorter and there are different degrees of bending, even annular cracks occur in the local area.
In order to understand the fracture law of rock by shock wave in deep water, an electric pulse fracturing device with hydrostatic pressure up to 35 MPa was established, which can simulate the confining pressure of 3 000 m underground. The experiments of plasma impact fracturing under different hydrostatic pressures were carried out. The maximum operating parameter of the fracturing device is 20 kV/40 kJ. Six sandstones were fractured by electric pulse under the hydrostatic pressure which ranges from 0 to 25 MPa. The experimental results show that the length and width of fracture decrease significantly with the increase of hydrostatic pressure under the same energy. So the destroy range of shock wave decreases and the porosity and permeability decline with the increase of confining pressure. The hydrostatic pressure has obvious influence on the formation, distribution and growth of the crack after impact fracture. Compared with the cracks formed by atmospheric pressure, cracks are concentrated in the electrode. The number of cracks is more but the length is shorter and there are different degrees of bending, even annular cracks occur in the local area.
2018, 38(5): 1057-1063.
doi: 10.11883/bzycj-2017-0060
Abstract:
Aiming at the flame propagation problem of gas deflagration in a short tube with one end closed and the other end open, by referring to the flame propagation model proposed by Clanet, et al and Bychkov, et al, and under the condition of adiabatic and incompressible assumption, a mathematical model of flammable gas distribution and flame front propagation was obtained. By using gasoline vapor as experimental working substance, deflagration experiment was carried out based on a fully transparent experimental pipeline. The proposed model was validated by high-speed photography and schlieren images. Results show that under the condition of length-diameter ratios 4:1 to 10:1, this model can predict accurately the flammable gas interface position and flame front position in the flow field outside the open end. Above results extend the original theory to outside field calculation, and have certain application value in flammable gas explosion protection and safety design.
Aiming at the flame propagation problem of gas deflagration in a short tube with one end closed and the other end open, by referring to the flame propagation model proposed by Clanet, et al and Bychkov, et al, and under the condition of adiabatic and incompressible assumption, a mathematical model of flammable gas distribution and flame front propagation was obtained. By using gasoline vapor as experimental working substance, deflagration experiment was carried out based on a fully transparent experimental pipeline. The proposed model was validated by high-speed photography and schlieren images. Results show that under the condition of length-diameter ratios 4:1 to 10:1, this model can predict accurately the flammable gas interface position and flame front position in the flow field outside the open end. Above results extend the original theory to outside field calculation, and have certain application value in flammable gas explosion protection and safety design.
2018, 38(5): 1071-1082.
doi: 10.11883/bzycj-2017-0070
Abstract:
Damaging effects of blast waves on tempered glasses were experimentally investigated to explore the blast damage threshold of the tempered glasses. The blast shock wave parameters were tested in each experiment, and the experimental overpressure-time histories were obtained. By analyzing the experimental data, the blast shock wave parameters were obtained, such as normally reflected overpressure, arrival time of the shock wave, duration of the normally reflected overpressure, normally reflected impulse, negative reflected overpressure, duration of the negative reflected overpressure, and negative reflected impulse. Compared with the results computed by the CONWEP program, the relative errors were small, which verified that the tested results were accurate and reliable. Meanwhile, the normally reflected parameters are greater than the corresponding negative reflected ones.
Damaging effects of blast waves on tempered glasses were experimentally investigated to explore the blast damage threshold of the tempered glasses. The blast shock wave parameters were tested in each experiment, and the experimental overpressure-time histories were obtained. By analyzing the experimental data, the blast shock wave parameters were obtained, such as normally reflected overpressure, arrival time of the shock wave, duration of the normally reflected overpressure, normally reflected impulse, negative reflected overpressure, duration of the negative reflected overpressure, and negative reflected impulse. Compared with the results computed by the CONWEP program, the relative errors were small, which verified that the tested results were accurate and reliable. Meanwhile, the normally reflected parameters are greater than the corresponding negative reflected ones.
2018, 38(5): 1083-1090.
doi: 10.11883/bzycj-2017-0078
Abstract:
In order to understand the law dominating the process of an ogival projectile perforating a medium thickness concrete target, the tests of the ogival projectiles of 60 mm diameter perforating concrete targets of (10-30)D thickness were carried out. The effect of concrete thickness on residual velocity was obtained in the tests. The meshless SPH method, combing the RHT concrete constitutive model and the p-α equation of state, was used to simulate perforation tests. Simulation results on perforation acceleration and damage process reveal that there are three stages in the perforation process, including catering, tunneling, and rear effect zone. Furthermore, the range of rear effect zone increases with increasing concrete thickness at the same projectile velocity. The comparison between the experimental results and the simulation results show that the current simulation model is able to simulate projectiles perforating concrete targets, and the simulation results provide insight into the perforation mechanisms.
In order to understand the law dominating the process of an ogival projectile perforating a medium thickness concrete target, the tests of the ogival projectiles of 60 mm diameter perforating concrete targets of (10-30)D thickness were carried out. The effect of concrete thickness on residual velocity was obtained in the tests. The meshless SPH method, combing the RHT concrete constitutive model and the p-α equation of state, was used to simulate perforation tests. Simulation results on perforation acceleration and damage process reveal that there are three stages in the perforation process, including catering, tunneling, and rear effect zone. Furthermore, the range of rear effect zone increases with increasing concrete thickness at the same projectile velocity. The comparison between the experimental results and the simulation results show that the current simulation model is able to simulate projectiles perforating concrete targets, and the simulation results provide insight into the perforation mechanisms.
2018, 38(5): 1091-1098.
doi: 10.11883/bzycj-2017-0082
Abstract:
In order to investigate spalling response and the spall threshold of Ti17 alloy under laser shock peening (LSP), the surface of a 5 mm-thick sample was shocked by multiple laser shots with the shot number ranging one to eight shots. The laser employed has a repetition rate of 1 Hz, the pulse width of 15 ns, the pulse energy of 30 J, and the spot size of 4 mm×4 mm. The surface morphology, the internal damage and the spall morphology after LSP were characterized by non-contact optical profiler, ultrasonic nondestructive testing technique and scanning electron microscope, respectively. The results indicate that the increment of the shot number from four to five results in increasing the depression depth of the surface up to 64.5%. The spall threshold is reached by LSP with continuous five shots. The spall thickness observed after LSP with five to eight shots ranges from 280 μm to 310 μm. The spall mechanism is due to the nucleation, growth and coalescence of the ductile micro-voids, leading to intragranular failure and transgranular failure. This work may provide valuable information for the optimization of integrated blisk rotators with LSP.
In order to investigate spalling response and the spall threshold of Ti17 alloy under laser shock peening (LSP), the surface of a 5 mm-thick sample was shocked by multiple laser shots with the shot number ranging one to eight shots. The laser employed has a repetition rate of 1 Hz, the pulse width of 15 ns, the pulse energy of 30 J, and the spot size of 4 mm×4 mm. The surface morphology, the internal damage and the spall morphology after LSP were characterized by non-contact optical profiler, ultrasonic nondestructive testing technique and scanning electron microscope, respectively. The results indicate that the increment of the shot number from four to five results in increasing the depression depth of the surface up to 64.5%. The spall threshold is reached by LSP with continuous five shots. The spall thickness observed after LSP with five to eight shots ranges from 280 μm to 310 μm. The spall mechanism is due to the nucleation, growth and coalescence of the ductile micro-voids, leading to intragranular failure and transgranular failure. This work may provide valuable information for the optimization of integrated blisk rotators with LSP.
2018, 38(5): 1099-1105.
doi: 10.11883/bzycj-2017-0087
Abstract:
In order to investigate the overpressure and flame propagation of premixed combustible gas explosion venting in a large space, experiments of different concentrations of ethylene gas and two different vent sizes have been carried out in a rectangular cavity of 1.21 m3. Meanwhile, three-dimensional numerical simulations have been performed to simulate the ethylene air explosion venting process with a 0.18 m2 vent area and a 7% concentration of ethylene gas. The results show that the overpressure has a different response with different vent size. When the small vent is used, the overpressure drops first and then rises, in which the second peak value is larger than the first one. The turbulence caused by the venting process increases significantly the flame front deformation and the flame propagation speed, resulting in the larger second peak. In contrast, for the large vent size, the second peak is lower. The simulated results are in good agreement with the experimental ones.
In order to investigate the overpressure and flame propagation of premixed combustible gas explosion venting in a large space, experiments of different concentrations of ethylene gas and two different vent sizes have been carried out in a rectangular cavity of 1.21 m3. Meanwhile, three-dimensional numerical simulations have been performed to simulate the ethylene air explosion venting process with a 0.18 m2 vent area and a 7% concentration of ethylene gas. The results show that the overpressure has a different response with different vent size. When the small vent is used, the overpressure drops first and then rises, in which the second peak value is larger than the first one. The turbulence caused by the venting process increases significantly the flame front deformation and the flame propagation speed, resulting in the larger second peak. In contrast, for the large vent size, the second peak is lower. The simulated results are in good agreement with the experimental ones.
2018, 38(5): 1106-1114.
doi: 10.11883/bzycj-2017-0109
Abstract:
The effects of blockage ratio, obstacles spacing and obstacles spatial position on the flame acceleration and explosion process of propane-air were studied in this paper.The unsteady combustion process was calculated by using the Reynolds averaged (RANS) equation and turbulent flame closure combustion model. The complex flow field around obstacles and the detailed mechanism of the interaction between the turbulent vortex and the flame surface were analyzed. The results showed that if the vortex zone is short compared to obstacles spacing, one portion of the flame would get in touch with the tube wall and some flame area would be reduced. For the higher blockage ratio, the flame area is the most important factor affecting the flame acceleration and the optimum flame acceleration can be achieved at the obstacles spacing of roughly one tube diameter. In contrast, the obstacles spacing shows little effect on the flame acceleration at lower value of blockage ratio. The flame interacted with vortex steadily during the process of flame propagation result in flame area enhancement that was counteracted by flame area extinction resulting from flame-wall interactions. However, as the blockage ratio increases to a critical value, the vorticity concentration area occupied most of the space between obstacles, therefore, the probability of contact between the flame and the tube wall became very small. In addition, the influence of the spatial position of the obstacles on the flame propagation was more significant. When the obstacles located on both sides of the pipe or in the middle of the pipe, the initial vortex intensity was too small to consume easily and there was no obvious flame folding. The most rapid flame propagation was observed when the obstacles was located on the unilateral side of the pipe, the turbulence vortex intensity in the flow field was the largest, the flame folding was also the most obvious with the process of chemical reaction.
The effects of blockage ratio, obstacles spacing and obstacles spatial position on the flame acceleration and explosion process of propane-air were studied in this paper.The unsteady combustion process was calculated by using the Reynolds averaged (RANS) equation and turbulent flame closure combustion model. The complex flow field around obstacles and the detailed mechanism of the interaction between the turbulent vortex and the flame surface were analyzed. The results showed that if the vortex zone is short compared to obstacles spacing, one portion of the flame would get in touch with the tube wall and some flame area would be reduced. For the higher blockage ratio, the flame area is the most important factor affecting the flame acceleration and the optimum flame acceleration can be achieved at the obstacles spacing of roughly one tube diameter. In contrast, the obstacles spacing shows little effect on the flame acceleration at lower value of blockage ratio. The flame interacted with vortex steadily during the process of flame propagation result in flame area enhancement that was counteracted by flame area extinction resulting from flame-wall interactions. However, as the blockage ratio increases to a critical value, the vorticity concentration area occupied most of the space between obstacles, therefore, the probability of contact between the flame and the tube wall became very small. In addition, the influence of the spatial position of the obstacles on the flame propagation was more significant. When the obstacles located on both sides of the pipe or in the middle of the pipe, the initial vortex intensity was too small to consume easily and there was no obvious flame folding. The most rapid flame propagation was observed when the obstacles was located on the unilateral side of the pipe, the turbulence vortex intensity in the flow field was the largest, the flame folding was also the most obvious with the process of chemical reaction.
2018, 38(5): 1115-1120.
doi: 10.11883/bzycj-2017-0091
Abstract:
Blasting is an indispensable construction method to human beings. However, in the meanwhile, the rock vibration caused by blasting is one of blasting hazards. Due to the complicated geology, the peak particle velocity is a random variable approximately. It does not have a general function relationship with the maximum dose Q and the distance R from blasting center. Therefore, the vibration can only be described by the theory of probability. In order to control the vibration intensity and get high reliability, it is necessary to calculate the probability that the peak particle velocity is less than the safety vibration velocity of the target facility. Based on the probability, the distribution of peak particle velocity is approximately regarded as the normal distribution. Then safety analysis of target facilities and calculation of safe explosives are carried out. Finally, through the application of the case, it is reasonable to calculate the dose by probability formula.
Blasting is an indispensable construction method to human beings. However, in the meanwhile, the rock vibration caused by blasting is one of blasting hazards. Due to the complicated geology, the peak particle velocity is a random variable approximately. It does not have a general function relationship with the maximum dose Q and the distance R from blasting center. Therefore, the vibration can only be described by the theory of probability. In order to control the vibration intensity and get high reliability, it is necessary to calculate the probability that the peak particle velocity is less than the safety vibration velocity of the target facility. Based on the probability, the distribution of peak particle velocity is approximately regarded as the normal distribution. Then safety analysis of target facilities and calculation of safe explosives are carried out. Finally, through the application of the case, it is reasonable to calculate the dose by probability formula.
High-frequency spiral detonation end-on records of premixed C2H2+2.5O2 with different argon dilution
2018, 38(5): 1121-1129.
doi: 10.11883/bzycj-2017-0098
Abstract:
In order to study the internal structure of premixed gas detonation, detonation experiments and calculation analysis of C2H2+2.5O2 premixed gas diluted with different concentrations of argon were performed. Firstly, the detonation experiment was carried out in a pipe with an internal diameter of 63.5 mm. The detonation end-on structures of C2H2+2.5O2 premixed gas under different initial pressures were recorded by using smoke glass. Digital image processing was used to analyze the three-point of smoked glass records to reduce human errors. Then, the regular graphics were obtained after the examination of experimental results, the calculations of experimental results were performed using a verified program. From the end-on structure, the closed graph is fitted with circle. The uniformity of cell size was expressed by the variance of cell radius. The regularity of the distribution of cell lattices was expressed by the variance of the distance between the centers of adjacent cells. By comparing the variance of the radius and the variance of the center distance with the change of cell number in different argon dilution, the size and distribution regulation of C2H2+2.5O2 premixed gas under different argon dilution were given. With the increase of argon concentration, the size and distribution of the cell is more regular.
In order to study the internal structure of premixed gas detonation, detonation experiments and calculation analysis of C2H2+2.5O2 premixed gas diluted with different concentrations of argon were performed. Firstly, the detonation experiment was carried out in a pipe with an internal diameter of 63.5 mm. The detonation end-on structures of C2H2+2.5O2 premixed gas under different initial pressures were recorded by using smoke glass. Digital image processing was used to analyze the three-point of smoked glass records to reduce human errors. Then, the regular graphics were obtained after the examination of experimental results, the calculations of experimental results were performed using a verified program. From the end-on structure, the closed graph is fitted with circle. The uniformity of cell size was expressed by the variance of cell radius. The regularity of the distribution of cell lattices was expressed by the variance of the distance between the centers of adjacent cells. By comparing the variance of the radius and the variance of the center distance with the change of cell number in different argon dilution, the size and distribution regulation of C2H2+2.5O2 premixed gas under different argon dilution were given. With the increase of argon concentration, the size and distribution of the cell is more regular.
2018, 38(5): 1130-1136.
doi: 10.11883/bzycj-2017-0101
Abstract:
In order to investigate explosion characteristics of micro-sized aluminum dust, a series of experiments were carried out to reveal the influences of ignition delay time, dust particle size and dust concentration on explosion parameters of aluminum dust using a 20 L nearly spherical dust explosion experimental system. The results show that:when the ignition delay time was within 20-120 ms, the maximum explosion pressure and maximum rate of pressure rise of aluminum dust initially increased but then decreased, the optimum ignition delay time increased with increasing particle size. The maximum explosion pressure of aluminum dust with particle size greater than 8.12 μm increased with decreasing particle size. Moreover, when the particle size is greater than 8.12 μm and the dust concentration range is 80-440 g/m3, the maximum explosion pressure and pressure rise rate of aluminum dust increased at beginning and then decreased, in addition, the smaller the dust particle size, the lower the dust concentration corresponding to the most violent explosion.
In order to investigate explosion characteristics of micro-sized aluminum dust, a series of experiments were carried out to reveal the influences of ignition delay time, dust particle size and dust concentration on explosion parameters of aluminum dust using a 20 L nearly spherical dust explosion experimental system. The results show that:when the ignition delay time was within 20-120 ms, the maximum explosion pressure and maximum rate of pressure rise of aluminum dust initially increased but then decreased, the optimum ignition delay time increased with increasing particle size. The maximum explosion pressure of aluminum dust with particle size greater than 8.12 μm increased with decreasing particle size. Moreover, when the particle size is greater than 8.12 μm and the dust concentration range is 80-440 g/m3, the maximum explosion pressure and pressure rise rate of aluminum dust increased at beginning and then decreased, in addition, the smaller the dust particle size, the lower the dust concentration corresponding to the most violent explosion.
2018, 38(5): 1137-1144.
doi: 10.11883/bzycj-2017-0107
Abstract:
Dynamic shear properties and failure mechanism of Ti-6Al-4V were studied at strain rates in excess of 104 s-1, with a new loading method based on the split Hopkinson pressure bar (SHPB) technique. The shear stress-shear strain curves and failure parameters of Ti-6Al-4V were acquired in a wide range of high shear strain rates. It is found that the flow stress of the material shows an obvious strain rate hardening effect. With the increase of strain rates, the failure stress of the material increases gradually, while the failure strain decreases. The loading process was modeled by ABAQUS/Explicit software. The results show that the shear zone material is substantially in the state of plane shear. The tested stress-strain curves have good agreement with the simulated results. The fracture surface examination shows that with the increase of strain rate, the failure of Ti-6Al-4V is closely related to the different behaviors of dimples, and it indicates an evolution process from dimples and tensile dimples to steps and river patterns. The fracture analyses show that the failure mode of the material is mainly ductile fracture.
Dynamic shear properties and failure mechanism of Ti-6Al-4V were studied at strain rates in excess of 104 s-1, with a new loading method based on the split Hopkinson pressure bar (SHPB) technique. The shear stress-shear strain curves and failure parameters of Ti-6Al-4V were acquired in a wide range of high shear strain rates. It is found that the flow stress of the material shows an obvious strain rate hardening effect. With the increase of strain rates, the failure stress of the material increases gradually, while the failure strain decreases. The loading process was modeled by ABAQUS/Explicit software. The results show that the shear zone material is substantially in the state of plane shear. The tested stress-strain curves have good agreement with the simulated results. The fracture surface examination shows that with the increase of strain rate, the failure of Ti-6Al-4V is closely related to the different behaviors of dimples, and it indicates an evolution process from dimples and tensile dimples to steps and river patterns. The fracture analyses show that the failure mode of the material is mainly ductile fracture.
2018, 38(5): 1145-1154.
doi: 10.11883/bzycj-2017-0119
Abstract:
In this paper, experiments and numerical simulation were conducted to study the damage effect of shaped charges exploding underwater on cabins near the shipboard, and discussed the propagation law of shock wave in multimedia structure and damage mechanism of the structure, providing reference to the design of protective structures. Results show that under the same explosive equivalent condition, explosives can only damage the first cabin of the cabins near the shipboard, the multi-media structure has a strong attenuation effect on shock wave, and the penetrator formed by shaped charge can cause perforation of front board and back board of the second cabin. The diameter of the hole is 1/3-1/2 of the charge. The enlargement of the liquid tank or the thickening of the liquid tank backboard can enhance the anti-explosion ability of the cabin near the shipboard.
In this paper, experiments and numerical simulation were conducted to study the damage effect of shaped charges exploding underwater on cabins near the shipboard, and discussed the propagation law of shock wave in multimedia structure and damage mechanism of the structure, providing reference to the design of protective structures. Results show that under the same explosive equivalent condition, explosives can only damage the first cabin of the cabins near the shipboard, the multi-media structure has a strong attenuation effect on shock wave, and the penetrator formed by shaped charge can cause perforation of front board and back board of the second cabin. The diameter of the hole is 1/3-1/2 of the charge. The enlargement of the liquid tank or the thickening of the liquid tank backboard can enhance the anti-explosion ability of the cabin near the shipboard.
2018, 38(5): 1155-1164.
doi: 10.11883/bzycj-2017-0387
Abstract:
Using the control volume method to describe annular an airtight airbag, we simulated the water entry process of a projectile and its annular airtight airbag based on LS-DYNA combined with the fluid-solid coupling algorithm. We divided this process into seven stages, i.e. those of the projectile slamming water, its air bag falling into water, decelerating in water-entry, hovering in water, floating upward in water, floating out of water, floating on the water surface. We analyzed the projectile's attitude change, deceleration, water entry depth and airbag in different stages in vertical and oblique water-entry. Then we examined the interaction between water and the airbag, covering the changes of the internal pressure, the resultant force of water to the airbag, the relationship between airbag's internal pressure and speed of the water-entry. The results show that the change of the internal pressure of the airbag is mainly affected by the water-entry depth, the movement speed, and the tension of the connecting rope. Further, we calculated the water-entry depth, the deceleration time and the tension peak of the connecting rope under the airbag's different initial internal pressures, and found that the water-entry depth and the deceleration time decrease with the increase of the airbag's initial pressure, while the tension peak of the corresponding connecting rope exhibited an opposite tendency. Therefore, it is necessary to consider the buffering effect, deceleration effect, airbag safety and other factors in the design of airbag parameters.
Using the control volume method to describe annular an airtight airbag, we simulated the water entry process of a projectile and its annular airtight airbag based on LS-DYNA combined with the fluid-solid coupling algorithm. We divided this process into seven stages, i.e. those of the projectile slamming water, its air bag falling into water, decelerating in water-entry, hovering in water, floating upward in water, floating out of water, floating on the water surface. We analyzed the projectile's attitude change, deceleration, water entry depth and airbag in different stages in vertical and oblique water-entry. Then we examined the interaction between water and the airbag, covering the changes of the internal pressure, the resultant force of water to the airbag, the relationship between airbag's internal pressure and speed of the water-entry. The results show that the change of the internal pressure of the airbag is mainly affected by the water-entry depth, the movement speed, and the tension of the connecting rope. Further, we calculated the water-entry depth, the deceleration time and the tension peak of the connecting rope under the airbag's different initial internal pressures, and found that the water-entry depth and the deceleration time decrease with the increase of the airbag's initial pressure, while the tension peak of the corresponding connecting rope exhibited an opposite tendency. Therefore, it is necessary to consider the buffering effect, deceleration effect, airbag safety and other factors in the design of airbag parameters.
2018, 38(5): 1165-1171.
doi: 10.11883/bzycj-2017-0116
Abstract:
Conventional measurements in SHPB are based on recording the strain profiles on the incident and transmitted bars with strain gauges, and require good adhesion between the strain gauge and bars, which strongly depends on the skill of an operator. In this paper, the all fiber laser interferometry technique with two fiber focusers based on the principle of Doppler frequency shift is used to establish a non-contact optical measurement system for SHPB. The monitoring objective of the new measurement system is the particle velocity that can be easily converted into strain and stress by means of stress wave propagation. For the ductile and brittle materials, two measurement methods by using of laser normal irradiation and laser obliqueirradiation were proposed, respectively. Taking aluminum alloy and PZT ceramics as examples, the validity of the two optical measurement systems was verified by comparing with the traditional SHPB measurement results and the DIC measurement results. The laser interferometry technique has several advantages over traditional strain gauge measurements. It is non-calibrating, high repeatable and high reliability, which is helpful to realize the standardization of SHPB measurement system.
Conventional measurements in SHPB are based on recording the strain profiles on the incident and transmitted bars with strain gauges, and require good adhesion between the strain gauge and bars, which strongly depends on the skill of an operator. In this paper, the all fiber laser interferometry technique with two fiber focusers based on the principle of Doppler frequency shift is used to establish a non-contact optical measurement system for SHPB. The monitoring objective of the new measurement system is the particle velocity that can be easily converted into strain and stress by means of stress wave propagation. For the ductile and brittle materials, two measurement methods by using of laser normal irradiation and laser obliqueirradiation were proposed, respectively. Taking aluminum alloy and PZT ceramics as examples, the validity of the two optical measurement systems was verified by comparing with the traditional SHPB measurement results and the DIC measurement results. The laser interferometry technique has several advantages over traditional strain gauge measurements. It is non-calibrating, high repeatable and high reliability, which is helpful to realize the standardization of SHPB measurement system.
2018, 38(5): 1172-1180.
doi: 10.11883/bzycj-2017-0410
Abstract:
To explore the directional-control blasting mechanism of a split-tube charge holder, a model was established by coupling explosive, a split-tube, and air. On the basis of the experimental results of the double split-tube charge holder by the high-speed schlieren system, the established model was used to carry out numerical simulations to investigate the interaction of shock waves, the spatial and temporal distribution of pressure in the explosion fields, and the morphological changes of the split-tube. The investigated results show that in the explosion processes of the split-tube charge holder, the split-tube can effectively control the energy release of explosive and the dynamic behavior of detonation gas; the pressure in the cutting direction appears earlier and it is higher than those in the non-cutting directions; under the joint action of the explosion shock waves and the detonation gas, the curvature of the split-tube decreases continuously and develops along the axial direction of the split-tube with the same deformation characteristics from the initiation detonation point; the numerical simulation results are in agreement with the experimental ones.
To explore the directional-control blasting mechanism of a split-tube charge holder, a model was established by coupling explosive, a split-tube, and air. On the basis of the experimental results of the double split-tube charge holder by the high-speed schlieren system, the established model was used to carry out numerical simulations to investigate the interaction of shock waves, the spatial and temporal distribution of pressure in the explosion fields, and the morphological changes of the split-tube. The investigated results show that in the explosion processes of the split-tube charge holder, the split-tube can effectively control the energy release of explosive and the dynamic behavior of detonation gas; the pressure in the cutting direction appears earlier and it is higher than those in the non-cutting directions; under the joint action of the explosion shock waves and the detonation gas, the curvature of the split-tube decreases continuously and develops along the axial direction of the split-tube with the same deformation characteristics from the initiation detonation point; the numerical simulation results are in agreement with the experimental ones.
