2015 Vol. 35, No. 2
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2015, 35(2): 145-156.
doi: 10.11883/1001-1455(2015)02-0145-12
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Abstract:
Laser-induced stress waves can deliver ramp compression on solid materials with very high strain rates, and it is one of the newly-developed dynamic high-pressure methods in decades. Distinct from the conventional methods, laser ramp compression can reach terapascal pressures smoothly from ambient pressure with a high strain rate 106-109 s-1, but the sample is still in solid state. During the rapid loading process, the thermodynamic state, dynamic characteristics, and in situ microstructure can all be probed by the advanced diagnostic technology. This method is becoming an important and new approach to further investigation on high-pressure physics, equation of state, and rate-dependent material dynamics. In this paper, the history, principle, diagnostics and main breakthroughs of laser ramp compression are reviewed and expected.
Laser-induced stress waves can deliver ramp compression on solid materials with very high strain rates, and it is one of the newly-developed dynamic high-pressure methods in decades. Distinct from the conventional methods, laser ramp compression can reach terapascal pressures smoothly from ambient pressure with a high strain rate 106-109 s-1, but the sample is still in solid state. During the rapid loading process, the thermodynamic state, dynamic characteristics, and in situ microstructure can all be probed by the advanced diagnostic technology. This method is becoming an important and new approach to further investigation on high-pressure physics, equation of state, and rate-dependent material dynamics. In this paper, the history, principle, diagnostics and main breakthroughs of laser ramp compression are reviewed and expected.
2015, 35(2): 157-163.
doi: 10.11883/1001-1455(2015)02-0157-07
Abstract:
In this paper, the method of obtaining parameters for JWL equation of state is investigated. The importance of JWL parameters considered detonation parameters is analyzed using simulation and theoretical calculation. Isentropic adiabatic index and detonation pressure of detonation product are calculated according to cylinder test. The methodology process for obtaining JWL parameters of ideal detonation product considered detonation parameters is established. The JWL parameters of two typical explosive are obtained with the application of this method according to published cylinder experimental result. The results of numerical simulation agree with the cylinder test so that the JWL parameters are reasonable and reliable.
In this paper, the method of obtaining parameters for JWL equation of state is investigated. The importance of JWL parameters considered detonation parameters is analyzed using simulation and theoretical calculation. Isentropic adiabatic index and detonation pressure of detonation product are calculated according to cylinder test. The methodology process for obtaining JWL parameters of ideal detonation product considered detonation parameters is established. The JWL parameters of two typical explosive are obtained with the application of this method according to published cylinder experimental result. The results of numerical simulation agree with the cylinder test so that the JWL parameters are reasonable and reliable.
2015, 35(2): 164-170.
doi: 10.11883/1001-1455(2015)02-0164-07
Abstract:
A finite element model was established for the head car of a high-speed train and its crashing progresses with a rigid wall at different speeds, simulated by using LS-DYNA software. It is found that when a crash occurs the draft sill deforms mainly in the Euler bending mode, which is harmful to buffering and energy absorption. Based on the understanding from the crashworthiness analysis of the original design, we propose to redesign the structure of the draft sill through adding square tubes with round corners as energy-absorbing tubes, which are either filled with aluminum foam or not. Two different sizes are chosen, thus four schemes are formed. The results of numerical simulation show that, compared to the original design, the energy absorption capacity in all of the new schemes has greatly improved, and the peak force on the rigid wall decreases in a certain extend. The scheme with the tubes having large radius of round corner, thick thickness and aluminum foam filler has the most obvious improvement.
A finite element model was established for the head car of a high-speed train and its crashing progresses with a rigid wall at different speeds, simulated by using LS-DYNA software. It is found that when a crash occurs the draft sill deforms mainly in the Euler bending mode, which is harmful to buffering and energy absorption. Based on the understanding from the crashworthiness analysis of the original design, we propose to redesign the structure of the draft sill through adding square tubes with round corners as energy-absorbing tubes, which are either filled with aluminum foam or not. Two different sizes are chosen, thus four schemes are formed. The results of numerical simulation show that, compared to the original design, the energy absorption capacity in all of the new schemes has greatly improved, and the peak force on the rigid wall decreases in a certain extend. The scheme with the tubes having large radius of round corner, thick thickness and aluminum foam filler has the most obvious improvement.
2015, 35(2): 171-176.
doi: 10.11883/1001-1455(2015)02-0171-06
Abstract:
The experimental investigations on dynamic buckling of brass and steel cylindrical shell under axial impact were carried out using drop hammer as loading apparatus. Multiple buckling models are observed and the time histories of impact force were recorded. The experimental results show that the steel cylindrical shell buckled progressively and the brass cylindrical shell occur dynamic plastic buckling (the entire length of a cylindrical shell wrinkles before the development of large radial displacements) when they subjected impact from a mass in relatively low velocity. These results confirm that the dynamic plastic buckling does not necessarily require high impact velocity. This conclusion conflicts with the established perception that the high impact velocity is a necessary condition for dynamic plastic buckling.
The experimental investigations on dynamic buckling of brass and steel cylindrical shell under axial impact were carried out using drop hammer as loading apparatus. Multiple buckling models are observed and the time histories of impact force were recorded. The experimental results show that the steel cylindrical shell buckled progressively and the brass cylindrical shell occur dynamic plastic buckling (the entire length of a cylindrical shell wrinkles before the development of large radial displacements) when they subjected impact from a mass in relatively low velocity. These results confirm that the dynamic plastic buckling does not necessarily require high impact velocity. This conclusion conflicts with the established perception that the high impact velocity is a necessary condition for dynamic plastic buckling.
2015, 35(2): 177-183.
doi: 10.11883/1001-1455(2015)02-0177-07
Abstract:
With explosion pressure simulator, blast experiments were carried out to investigate the deformation and damage of concrete (RC) beams. The experimental design and parameters are described in detail. The experimental result shows the failure characteristics of RC beams and the role that rebars act. With LS-DYNA, three-dimensional separated finite element models of RC beams were established to simulate the experiment. The simulation and experimental results are contrasted to investigate the damage mechanism and failure characteristics. The article also figures out the reason of simulation errors. The research provides reference for damage assessment and anti-blast design.
With explosion pressure simulator, blast experiments were carried out to investigate the deformation and damage of concrete (RC) beams. The experimental design and parameters are described in detail. The experimental result shows the failure characteristics of RC beams and the role that rebars act. With LS-DYNA, three-dimensional separated finite element models of RC beams were established to simulate the experiment. The simulation and experimental results are contrasted to investigate the damage mechanism and failure characteristics. The article also figures out the reason of simulation errors. The research provides reference for damage assessment and anti-blast design.
2015, 35(2): 184-190.
doi: 10.11883/1001-1455(2015)02-0184-07
Abstract:
Explosive networks are the key components to the initiations of aimed warheads and shaped charge warheads, which become the important way for the logicalization of ammunition detonating system. For designing and evaluating the reliability of an explosive network, it is important to find out the quantitative relationship between the reliability characteristic quantities and the major factors affecting the reliability. The quantitative models between the detonation velocity and its main factors were determined by the orthogonal and uniform experiments. First, the orthogonal experiment was carried out to select seven major factors from the twenty-three possible factors, and then these major factors were applied to create an effective uniform experiment to do regression analysis on the experimental results, finally the quantitative models between the detonation velocity and the main factors were figured out.
Explosive networks are the key components to the initiations of aimed warheads and shaped charge warheads, which become the important way for the logicalization of ammunition detonating system. For designing and evaluating the reliability of an explosive network, it is important to find out the quantitative relationship between the reliability characteristic quantities and the major factors affecting the reliability. The quantitative models between the detonation velocity and its main factors were determined by the orthogonal and uniform experiments. First, the orthogonal experiment was carried out to select seven major factors from the twenty-three possible factors, and then these major factors were applied to create an effective uniform experiment to do regression analysis on the experimental results, finally the quantitative models between the detonation velocity and the main factors were figured out.
2015, 35(2): 191-196.
doi: 10.11883/1001-1455(2015)02-0191-06
Abstract:
An experimental equation of CFBG sensor for detonation velocity measurement which was based on the flatness of ASE light source and CFBG reflection spectrum, was quantitatively established for the first time. The CFBG length could be calculated by the theoretical relation between it and the CFBG reflection spectrum line-width, which was measured experimentally. The constant of the CFBG sensor was fitted by the experimental data. The side detonation-wave velocity of RDX/TNT (60/40) was measured with 3.4% error compared to the publication value.
An experimental equation of CFBG sensor for detonation velocity measurement which was based on the flatness of ASE light source and CFBG reflection spectrum, was quantitatively established for the first time. The CFBG length could be calculated by the theoretical relation between it and the CFBG reflection spectrum line-width, which was measured experimentally. The constant of the CFBG sensor was fitted by the experimental data. The side detonation-wave velocity of RDX/TNT (60/40) was measured with 3.4% error compared to the publication value.
2015, 35(2): 197-202.
doi: 10.11883/1001-1455(2015)02-0197-06
Abstract:
The concept, application back ground and generation of strong detonation were briefly introduced. The JWLT equation of state was embeded in one dimensional hydrodynamic program. The experimental model of strong detonation was simulated with the program. The pressure and density distribution of production of explosive were drew, and the existence of strong detonation was shown. The velocity curves of second flyer free surface are in good agreement with the experimental results. This work may afford validation and reference for studying the strong detonation.
The concept, application back ground and generation of strong detonation were briefly introduced. The JWLT equation of state was embeded in one dimensional hydrodynamic program. The experimental model of strong detonation was simulated with the program. The pressure and density distribution of production of explosive were drew, and the existence of strong detonation was shown. The velocity curves of second flyer free surface are in good agreement with the experimental results. This work may afford validation and reference for studying the strong detonation.
2015, 35(2): 203-207.
doi: 10.11883/1001-1455(2015)02-0203-05
Abstract:
With the Euler equations and a two-step chemical reaction model, a numerical investigation of the wedge-induced oblique detonation wave (ODW) at low inflow Mach number is performed in this paper. Its stabilization process and stationary structure are studied in detail via numerical simulation. It is found that the upstream propagating of an attached ODW at low inflow Mach number is resulted from the effect of the high pressure region behind the induction region. In this condition, the ODW is always stable in the vicinity of the wedge tip. The length of the induction region is about one millimeter. When the ODW is triggered near the wedge tip, it will stay in its vicinity.
With the Euler equations and a two-step chemical reaction model, a numerical investigation of the wedge-induced oblique detonation wave (ODW) at low inflow Mach number is performed in this paper. Its stabilization process and stationary structure are studied in detail via numerical simulation. It is found that the upstream propagating of an attached ODW at low inflow Mach number is resulted from the effect of the high pressure region behind the induction region. In this condition, the ODW is always stable in the vicinity of the wedge tip. The length of the induction region is about one millimeter. When the ODW is triggered near the wedge tip, it will stay in its vicinity.
2015, 35(2): 208-214.
doi: 10.11883/1001-1455(2015)02-0208-07
Abstract:
In order to study the influence of the spoiler on the overturning angular velocity of the ammunition in the dispensing process, the central-gas dispersing interior ballistic process was modeled and simulated by a two-dimensional, two-phase flow model. The comparison between the numerical simulation results and the test results proved that the above model was feasible. The comparative analysis of the flow field structure and the ejector stress states shows that the turning torque of the ejector can be enhanced by elevating the spoiler when the holes of the gas generator are on the top of the spoiler. And the final result can provide a theoretical basis to improve the submunition dispersing system.
In order to study the influence of the spoiler on the overturning angular velocity of the ammunition in the dispensing process, the central-gas dispersing interior ballistic process was modeled and simulated by a two-dimensional, two-phase flow model. The comparison between the numerical simulation results and the test results proved that the above model was feasible. The comparative analysis of the flow field structure and the ejector stress states shows that the turning torque of the ejector can be enhanced by elevating the spoiler when the holes of the gas generator are on the top of the spoiler. And the final result can provide a theoretical basis to improve the submunition dispersing system.
2015, 35(2): 215-221.
doi: 10.11883/1001-1455(2015)02-0215-07
Abstract:
We carried out the analysis of aircraft crashing on the concrete structures through numerical simulation and dynamic analysis using the matured software of ANSYS/LS-DYNA. The analysis uses the same contacting algorithm for four different material models and the results of damage effects are discussed in detail. The numerical simulation results are listed as follows. First, all of four material models can simulate the crashing process of penetration, spallation, and some other local damage effects. Second, if the damage is in front and back side, multiplying with velocity is considered, though the results of MAT072R3 and MAT084 are close to each other. The result of MAT111 is not very close to the previous two models. The model of MAT159 is significantly different from the results of 3 models mentioned above. The results of this research provide some basic parameters for subsequent evaluation of concrete structures resisting under aircraft impact.
We carried out the analysis of aircraft crashing on the concrete structures through numerical simulation and dynamic analysis using the matured software of ANSYS/LS-DYNA. The analysis uses the same contacting algorithm for four different material models and the results of damage effects are discussed in detail. The numerical simulation results are listed as follows. First, all of four material models can simulate the crashing process of penetration, spallation, and some other local damage effects. Second, if the damage is in front and back side, multiplying with velocity is considered, though the results of MAT072R3 and MAT084 are close to each other. The result of MAT111 is not very close to the previous two models. The model of MAT159 is significantly different from the results of 3 models mentioned above. The results of this research provide some basic parameters for subsequent evaluation of concrete structures resisting under aircraft impact.
2015, 35(2): 222-228.
doi: 10.11883/1001-1455(2015)02-0222-07
Abstract:
The simulation analysis of the impact test of 1/7.5 scaled aircraft model impacting the steel plated concrete walls is carried out by using finite element code of ANSYS/LSDYNA. Two models of different material (i.e. Winfrith model and CSCM model) are used to simulate the concrete. The comparison analysis of damage profile of walls and residual velocity of aircraft engine between the simulation results and test results is presented. The results indicate that the damage modes of the impact simulations are in agreement with that of the experiment. Furthermore, Winfrith concrete model is better for simulating the nonlinear performance of concrete with big strain and high strain rate than CSCM concrete model. It is verified that not only the selection of the material constitutive models for the steel plated concrete wall and aircraft model but also the entire analysis process is appropriate and effective.
The simulation analysis of the impact test of 1/7.5 scaled aircraft model impacting the steel plated concrete walls is carried out by using finite element code of ANSYS/LSDYNA. Two models of different material (i.e. Winfrith model and CSCM model) are used to simulate the concrete. The comparison analysis of damage profile of walls and residual velocity of aircraft engine between the simulation results and test results is presented. The results indicate that the damage modes of the impact simulations are in agreement with that of the experiment. Furthermore, Winfrith concrete model is better for simulating the nonlinear performance of concrete with big strain and high strain rate than CSCM concrete model. It is verified that not only the selection of the material constitutive models for the steel plated concrete wall and aircraft model but also the entire analysis process is appropriate and effective.
2015, 35(2): 229-235.
doi: 10.11883/1001-1455(2015)02-0229-07
Abstract:
To the case of heat transfer, the flowing process of jet flow impacting on a plate vertically is simulated by employing RNGk-ε turbulence model, which is compared with the experimental data, to verify the feasibility of the model. Based on the simulating results, the models of the impact of supersonic jet flow on plate vertically and on submerged plate are built respectively by considering the parameters of rocket nozzle entrance as the inlet conditions. In addition, the distributions of the Nusselt number and temperature are calculated under different impacting conditions. Moreover the characteristics and factors of supersonic jet flow heat transfer are analyzed. The results show the range of Nusselt number under different impacting distances are between 14D and 18D, and reflect that the impacting distance and jet flow temperature are the key factors which influence the heat transfer rate. Furthermore, when the impacting distance increases, the heat transfer rate decreases. In contrast, the higher the temperature of jet flow on the plate is, the greater the efficiency of heat transfer is.
To the case of heat transfer, the flowing process of jet flow impacting on a plate vertically is simulated by employing RNGk-ε turbulence model, which is compared with the experimental data, to verify the feasibility of the model. Based on the simulating results, the models of the impact of supersonic jet flow on plate vertically and on submerged plate are built respectively by considering the parameters of rocket nozzle entrance as the inlet conditions. In addition, the distributions of the Nusselt number and temperature are calculated under different impacting conditions. Moreover the characteristics and factors of supersonic jet flow heat transfer are analyzed. The results show the range of Nusselt number under different impacting distances are between 14D and 18D, and reflect that the impacting distance and jet flow temperature are the key factors which influence the heat transfer rate. Furthermore, when the impacting distance increases, the heat transfer rate decreases. In contrast, the higher the temperature of jet flow on the plate is, the greater the efficiency of heat transfer is.
2015, 35(2): 236-242.
doi: 10.11883/1001-1455(2015)02-0236-07
Abstract:
The shock environment of floating shock platform for the equipment and the response of ship board equipment under different shock environment were studied by numerical simulation and theoretical analysis. Based on the calculation model of American intermediate floating shock platform, the shock environment of equipment base was compared with German BV specification. In order to analyze the difference of spectrum acceleration between the two systems in impact requirements of the equipment, numerical simulations for different ship board equipment were carried out. Through the modal method of virtual constraint boundary, a model for the multi-degree freedom system with basic excitation under different shock environment was proposed. Numerical analysis and theoretical results show that the spectrum acceleration of shock spectrum has little effect on the response of ship board equipment, but spectrum displacement and velocity have significant effect on equipment response. The response of multi-degree freedom system analyzed by theoretical calculations is consistent with the numerical simulation results. Meanwhile, during the design of floating shock platform, the influence of spectrum acceleration on equipment response does not need to be considered.
The shock environment of floating shock platform for the equipment and the response of ship board equipment under different shock environment were studied by numerical simulation and theoretical analysis. Based on the calculation model of American intermediate floating shock platform, the shock environment of equipment base was compared with German BV specification. In order to analyze the difference of spectrum acceleration between the two systems in impact requirements of the equipment, numerical simulations for different ship board equipment were carried out. Through the modal method of virtual constraint boundary, a model for the multi-degree freedom system with basic excitation under different shock environment was proposed. Numerical analysis and theoretical results show that the spectrum acceleration of shock spectrum has little effect on the response of ship board equipment, but spectrum displacement and velocity have significant effect on equipment response. The response of multi-degree freedom system analyzed by theoretical calculations is consistent with the numerical simulation results. Meanwhile, during the design of floating shock platform, the influence of spectrum acceleration on equipment response does not need to be considered.
2015, 35(2): 243-248.
doi: 10.11883/1001-1455(2015)02-0243-06
Abstract:
Broadside defensive structure is important for naval vessels to maintain vitality. A novel broadside defensive structure with macro negative Poisson's ratio is proposed to achieve higher anti-shock and anti-blast performance by design of auxetic honeycomb configuration. The process of an anti-ship missile impinging on and penetrating broadside structure is simulated by nonlinear finite element software. Effects of different design parameters on broadside structure, like auxetic honeycomb configurations, materials, sizes and thickness of honeycomb cell, are studied and compared. Numerical results indicate that counter-impingement capacity can be improved by adoption of auxetic broadside structure, and honeycomb cell with negative Poisson's ratio is better than that of common honeycomb cell on anti-blast performance.
Broadside defensive structure is important for naval vessels to maintain vitality. A novel broadside defensive structure with macro negative Poisson's ratio is proposed to achieve higher anti-shock and anti-blast performance by design of auxetic honeycomb configuration. The process of an anti-ship missile impinging on and penetrating broadside structure is simulated by nonlinear finite element software. Effects of different design parameters on broadside structure, like auxetic honeycomb configurations, materials, sizes and thickness of honeycomb cell, are studied and compared. Numerical results indicate that counter-impingement capacity can be improved by adoption of auxetic broadside structure, and honeycomb cell with negative Poisson's ratio is better than that of common honeycomb cell on anti-blast performance.
2015, 35(2): 249-254.
doi: 10.11883/1001-1455(2015)02-0249-06
Abstract:
The paper is aimed to experimentally probe the detonation characteristics of the binary fuel hydrogen/propane-air mixture. The experiments were conducted in an obstructed cylindrical tube with a 92-mm inner diameter and a 12-m length at normal pressure and temperature. Eleven instrument ports and eleven piezoelectric pressure transducers were adopted on the tube wall surface. A Schelkin spiral with a blockage ratio of 0.5 and a pitch with inner diameter as the tube and with the length of 3 m were used to accelerate the flame propagation until the detonation initiated. The studied binary fuel mixtures with equivalence ratio of 1.1 and hydrogen molar fraction varying from 0.5 to 1.0 were prepared by the partial pressure and ignited via a spark plug at about 15-mJ discharge energy. The detonation characteristic parameters such as velocity, pressure and cell size were achieved with pressure transducers and smoking foils, respectively. It can be therefore concluded that the self-sustained detonation is observed as follows: (ⅰ) detonation velocity ratiov/vCJ varies from 0.99 to 1.0 and pressure ratio p/pCJ changes from 0.8 to 1.2; (ⅱ) detonation cell size varies from 10 mm to 50 mm. When propane is added to hydrogen/air mixtures, the detonation velocity decreases, but the pressure and cell size inversely increase. The variation trends of the detonation parameters at the beginning change quickly because the detonation characteristics of hydrogen/propane-air mixtures are similar to those of hydrogen/air due to the larger hydrogen molar fraction. Afterwards, the trends gradually slow down because the increasing molar fraction of propane with heavier molecular mass in the mixtures which plays a dominant role in the binary fuels. At last, a relationship between detonation cell size and ZND chemical induction length was obtained. Thus, our conclusion can provide the experimental data in the hydrogen explosion hazard prevention.
The paper is aimed to experimentally probe the detonation characteristics of the binary fuel hydrogen/propane-air mixture. The experiments were conducted in an obstructed cylindrical tube with a 92-mm inner diameter and a 12-m length at normal pressure and temperature. Eleven instrument ports and eleven piezoelectric pressure transducers were adopted on the tube wall surface. A Schelkin spiral with a blockage ratio of 0.5 and a pitch with inner diameter as the tube and with the length of 3 m were used to accelerate the flame propagation until the detonation initiated. The studied binary fuel mixtures with equivalence ratio of 1.1 and hydrogen molar fraction varying from 0.5 to 1.0 were prepared by the partial pressure and ignited via a spark plug at about 15-mJ discharge energy. The detonation characteristic parameters such as velocity, pressure and cell size were achieved with pressure transducers and smoking foils, respectively. It can be therefore concluded that the self-sustained detonation is observed as follows: (ⅰ) detonation velocity ratiov/vCJ varies from 0.99 to 1.0 and pressure ratio p/pCJ changes from 0.8 to 1.2; (ⅱ) detonation cell size varies from 10 mm to 50 mm. When propane is added to hydrogen/air mixtures, the detonation velocity decreases, but the pressure and cell size inversely increase. The variation trends of the detonation parameters at the beginning change quickly because the detonation characteristics of hydrogen/propane-air mixtures are similar to those of hydrogen/air due to the larger hydrogen molar fraction. Afterwards, the trends gradually slow down because the increasing molar fraction of propane with heavier molecular mass in the mixtures which plays a dominant role in the binary fuels. At last, a relationship between detonation cell size and ZND chemical induction length was obtained. Thus, our conclusion can provide the experimental data in the hydrogen explosion hazard prevention.
2015, 35(2): 255-260.
doi: 10.11883/1001-1455(2015)02-0255-06
Abstract:
In order to study the influence of explosive parameter on the effect of explosion hardening of the Hadifield steel, detonation velocities of two different densities of explosive were tested respectively. The variation of internal hardness, tensile strength and impact toughness from the hardened surface to inside the material with depth was tested respectively. The hardness and impact toughness of the sample for triple explosion with the density of 1.38 g/cm3 are larger than those for twice explosion with the density of 1.48 g/cm3 at the same hardening depth. The tensile strength for triple explosion with the density of 1.38 g/cm3 is higher from the surface to 15 mm below the hardened surface but is lower from 15 mm down. For the hardness, tensile strength and impact hardened toughness consideration, the effect of explosion hardening for the smaller single impulse is better.
In order to study the influence of explosive parameter on the effect of explosion hardening of the Hadifield steel, detonation velocities of two different densities of explosive were tested respectively. The variation of internal hardness, tensile strength and impact toughness from the hardened surface to inside the material with depth was tested respectively. The hardness and impact toughness of the sample for triple explosion with the density of 1.38 g/cm3 are larger than those for twice explosion with the density of 1.48 g/cm3 at the same hardening depth. The tensile strength for triple explosion with the density of 1.38 g/cm3 is higher from the surface to 15 mm below the hardened surface but is lower from 15 mm down. For the hardness, tensile strength and impact hardened toughness consideration, the effect of explosion hardening for the smaller single impulse is better.
Frequency domain characteristic of secondary instrument in the shock overpressure measurement system
2015, 35(2): 261-266.
doi: 10.11883/1001-1455(2015)02-0261-06
Abstract:
The frequency domain characteristics of measurement system are determined by transducer and secondary instrument, and the former one has been widely studied. It is shown that peak value, positive phase duration and impulse are affected by secondary instrument. The ideal shock wave signal was constructed for its frequency characteristic analysis. The low frequency characteristic of adapter was also experimentally investigated. Five different filters were modeled, and their output under different cutoff frequencies was simulated with the ideal shock wave as input signal. The simulation and experimental results are summarized as follows: The low frequency characteristic of adapter has the influence to positive phase duration and impulse; Bessel filter is the best one for shock wave measurement system of the five filters; The peak value of shock wave is obviously affected by the filters cutoff frequency; And the shock wave signal with short positive phase duration needs higher system bandwidth.
The frequency domain characteristics of measurement system are determined by transducer and secondary instrument, and the former one has been widely studied. It is shown that peak value, positive phase duration and impulse are affected by secondary instrument. The ideal shock wave signal was constructed for its frequency characteristic analysis. The low frequency characteristic of adapter was also experimentally investigated. Five different filters were modeled, and their output under different cutoff frequencies was simulated with the ideal shock wave as input signal. The simulation and experimental results are summarized as follows: The low frequency characteristic of adapter has the influence to positive phase duration and impulse; Bessel filter is the best one for shock wave measurement system of the five filters; The peak value of shock wave is obviously affected by the filters cutoff frequency; And the shock wave signal with short positive phase duration needs higher system bandwidth.
2015, 35(2): 267-272.
doi: 10.11883/1001-1455(2015)02-0267-06
Abstract:
In order to develop a special detonation powerplant and ensure the accuracy of the work capacity of the detonation powerplant, the interior ballistic numerical simulation, optimal design and corresponding experimental verification technology of detonation powerplant were investigated. On the basis of getting physical model and analyzing working process of detonation powerplant, the interior ballistic mathematical model was established and calculated. According to the interior ballistic evaluation index of detonation powerplant, the objective function, the optimized interior ballistic design variables, and the constraint condition were obtained with the genetic algorithm. According to the similarity theory, the simulation test of pushing airliner door was carried out. It shows that the calculated results coincide with the test results, the interior ballistic mathematical model is reasonable, and the optimized interior ballistic result is acceptable.
In order to develop a special detonation powerplant and ensure the accuracy of the work capacity of the detonation powerplant, the interior ballistic numerical simulation, optimal design and corresponding experimental verification technology of detonation powerplant were investigated. On the basis of getting physical model and analyzing working process of detonation powerplant, the interior ballistic mathematical model was established and calculated. According to the interior ballistic evaluation index of detonation powerplant, the objective function, the optimized interior ballistic design variables, and the constraint condition were obtained with the genetic algorithm. According to the similarity theory, the simulation test of pushing airliner door was carried out. It shows that the calculated results coincide with the test results, the interior ballistic mathematical model is reasonable, and the optimized interior ballistic result is acceptable.
2015, 35(2): 273-277.
doi: 10.11883/1001-1455(2015)02-0273-05
Abstract:
Analysis on shock and vibration of nuclear explosion in limestone is difficult due to the forbidden law of nuclear test. Based on the blasting similarity law, simulation of shock and vibration of nuclear explosion in limestone based on chemical explosion is considered. Shock and vibration of nuclear and chemical explosion had been analyzed. The expression of equivalent weight coefficient between chemical and nuclear explosion is defined by stress wave and velocity and given by least square method. The expression can be used to calculate stress wave and velocity of nuclear explosion approximately.
Analysis on shock and vibration of nuclear explosion in limestone is difficult due to the forbidden law of nuclear test. Based on the blasting similarity law, simulation of shock and vibration of nuclear explosion in limestone based on chemical explosion is considered. Shock and vibration of nuclear and chemical explosion had been analyzed. The expression of equivalent weight coefficient between chemical and nuclear explosion is defined by stress wave and velocity and given by least square method. The expression can be used to calculate stress wave and velocity of nuclear explosion approximately.
2015, 35(2): 278-284.
doi: 10.11883/1001-1455(2015)02-0278-07
Abstract:
On the basis of the peak velocity decay law of blasting and the assumption of unstable rock dominant fissure, and using Euler equations to work out the load of peak value blasting which acts on unstable rocks, and correcting peak force, it figured out the time history of blasting inertia force. Dynamic physical model and calculation model for three kinds of unstable rock were set up. The calculation method of stability coefficient with three kinds of unstable rock was given by combining with the limit equilibrium method. Within the scope of blasting time, it takes the minimal stability coefficient as the dynamic stability coefficient of the whole unstable rock, and establishes three kinds of dynamic evaluation method of unstable rock. Taking unstable rocks in Taibaiyan of Wanzhou in Chongqing as an example, five typical unstable rocks were chose to work out the calculation of dynamic stability coefficient. The calculation result can well evaluate and reflect the dynamic characteristics of unstable rock blocks by the calculation method for dynamic stability coefficient of the three kinds of unstable rock blocks.
On the basis of the peak velocity decay law of blasting and the assumption of unstable rock dominant fissure, and using Euler equations to work out the load of peak value blasting which acts on unstable rocks, and correcting peak force, it figured out the time history of blasting inertia force. Dynamic physical model and calculation model for three kinds of unstable rock were set up. The calculation method of stability coefficient with three kinds of unstable rock was given by combining with the limit equilibrium method. Within the scope of blasting time, it takes the minimal stability coefficient as the dynamic stability coefficient of the whole unstable rock, and establishes three kinds of dynamic evaluation method of unstable rock. Taking unstable rocks in Taibaiyan of Wanzhou in Chongqing as an example, five typical unstable rocks were chose to work out the calculation of dynamic stability coefficient. The calculation result can well evaluate and reflect the dynamic characteristics of unstable rock blocks by the calculation method for dynamic stability coefficient of the three kinds of unstable rock blocks.
2015, 35(2): 285-288.
doi: 10.11883/1001-1455-(2015)02-0285-04
Abstract:
Detonators based on laser-driven flyers are less vulnerable to the strong electromagnetic interference and can use insensitive secondary explosives as initial explosives. Additionally, this technology has advantages in terms of improved flexibility and reliability. Hexanitrostilbene (HNS-Ⅳ) is the ideal candidate for use in laser-driven flyer initiation. Experiments were carried out to study the initiation of HNS-Ⅳ with the density of 1.5 g/cm3, by using laser-driven Al/Al2O3/Al multi-layer flyers and Al single-layer flyer at different laser energies. Within 217-245 mJ laser energies, the HNS-Ⅳ can be successfully detonated by Al/Al2O3/Al multi-layer flyers, while not be detonated by Al single-layer flyers under the above laser energies.
Detonators based on laser-driven flyers are less vulnerable to the strong electromagnetic interference and can use insensitive secondary explosives as initial explosives. Additionally, this technology has advantages in terms of improved flexibility and reliability. Hexanitrostilbene (HNS-Ⅳ) is the ideal candidate for use in laser-driven flyer initiation. Experiments were carried out to study the initiation of HNS-Ⅳ with the density of 1.5 g/cm3, by using laser-driven Al/Al2O3/Al multi-layer flyers and Al single-layer flyer at different laser energies. Within 217-245 mJ laser energies, the HNS-Ⅳ can be successfully detonated by Al/Al2O3/Al multi-layer flyers, while not be detonated by Al single-layer flyers under the above laser energies.
