2006 Vol. 26, No. 5
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2006, 26(5): 404-409.
doi: 10.11883/1001-1455(2006)05-0404-06
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Abstract:
Effect of after-burning on the blast power of SEFAE was studied by analyzing blast process of SEFAE warhead recorded by a high-speed video camera. By means of data obtained from SEFAE warhead field test and their TNT equivalency calculation, energy release of after-burning was quantificationally analyzed and compared with experimental results.Comparisons show that total energy and blast power are improved due to intense after-burning. The reaction mechanism between SEFAE and oxygen in air was explored and the way of enhancing SEFAE power was proposed.
Effect of after-burning on the blast power of SEFAE was studied by analyzing blast process of SEFAE warhead recorded by a high-speed video camera. By means of data obtained from SEFAE warhead field test and their TNT equivalency calculation, energy release of after-burning was quantificationally analyzed and compared with experimental results.Comparisons show that total energy and blast power are improved due to intense after-burning. The reaction mechanism between SEFAE and oxygen in air was explored and the way of enhancing SEFAE power was proposed.
2006, 26(5): 410-415.
doi: 10.11883/1001-1455(2006)05-0410-06
Abstract:
The dynamic properties of special metallic cellular materials are tested difficultly by using the traditional SHPB techniques. In order to experimentally determine the initial dynamic collapse strength, plateau stress and to investigate the strain-rate effect, based on the current SHPB equipment, the transfer function of the system was proposed by using the deconvolution technique in inverse analysis with computer simulation. The improved data processing system of the SHPB experiment provides an effective approach for experimental study on the dynamic properties of foam materials.
The dynamic properties of special metallic cellular materials are tested difficultly by using the traditional SHPB techniques. In order to experimentally determine the initial dynamic collapse strength, plateau stress and to investigate the strain-rate effect, based on the current SHPB equipment, the transfer function of the system was proposed by using the deconvolution technique in inverse analysis with computer simulation. The improved data processing system of the SHPB experiment provides an effective approach for experimental study on the dynamic properties of foam materials.
2006, 26(5): 416-422.
doi: 10.11883/1001-1455(2006)05-0416-07
Abstract:
An experimental investigation was carried out to study the static-compressive behavior and energy-absorption performance of a closed cellular Al-Cu alloy. The fitting curves of relative elastic modulus-relative density and relative plateau stress-relative density for a special range of density were built. It was found that good agreement could be achieved if the constants in Gibson's formulas for open cellular materials were revised to the constants determined by experiments. Furthermore, the energy-absorption performances of the closed cellular Al-Cu alloy for a special range of density were analyzed directly by constructing the Se- or Se- diagrams, where Se specific energy is the absorbed energy per unit mass. These diagrams may have good referential values for structural design.
An experimental investigation was carried out to study the static-compressive behavior and energy-absorption performance of a closed cellular Al-Cu alloy. The fitting curves of relative elastic modulus-relative density and relative plateau stress-relative density for a special range of density were built. It was found that good agreement could be achieved if the constants in Gibson's formulas for open cellular materials were revised to the constants determined by experiments. Furthermore, the energy-absorption performances of the closed cellular Al-Cu alloy for a special range of density were analyzed directly by constructing the Se- or Se- diagrams, where Se specific energy is the absorbed energy per unit mass. These diagrams may have good referential values for structural design.
2006, 26(5): 423-428.
doi: 10.11883/1001-1455(2006)05-0423-06
Abstract:
High-speed camera and optical microscope were used to study the fracture characteristics of the 45 steel cylinder and the effect of the heat treatment conditions on them. Results show that while the temper temperature rises, the intensity decreases and static fracture strain increases, the time of crack generation and resultant leakage in the outer surface of the 45 steel cylinder delays under detonation loading, at the same time the corresponding strain increases, the size of the fragment increases. The reason that the static mechanics characteristics and the dynamic fracture characteristic of the 45 steel are evidently different is that the buildup and the component of the materials microcosmic structure are greatly changed, i.e. static mechanics characteristic and dynamic fracture characteristic depend on the materials microcosmic structure.
High-speed camera and optical microscope were used to study the fracture characteristics of the 45 steel cylinder and the effect of the heat treatment conditions on them. Results show that while the temper temperature rises, the intensity decreases and static fracture strain increases, the time of crack generation and resultant leakage in the outer surface of the 45 steel cylinder delays under detonation loading, at the same time the corresponding strain increases, the size of the fragment increases. The reason that the static mechanics characteristics and the dynamic fracture characteristic of the 45 steel are evidently different is that the buildup and the component of the materials microcosmic structure are greatly changed, i.e. static mechanics characteristic and dynamic fracture characteristic depend on the materials microcosmic structure.
2006, 26(5): 429-433.
doi: 10.11883/1001-1455(2006)05-0429-05
Abstract:
The influencing factors of diamond's yield rate, such as, catalyzer, charge structure and initiation manners, were experimentally researched respectively. Experimental results show that diamond's yield rate increase greatly with MnCl2, Ni(CHOO)2, and CoCl2 as catalyzers, that diamond's yield rate with spherical charges is greater than that with cylindrical charges, and that to add the initiation points can increase the diamond's yield rate.
The influencing factors of diamond's yield rate, such as, catalyzer, charge structure and initiation manners, were experimentally researched respectively. Experimental results show that diamond's yield rate increase greatly with MnCl2, Ni(CHOO)2, and CoCl2 as catalyzers, that diamond's yield rate with spherical charges is greater than that with cylindrical charges, and that to add the initiation points can increase the diamond's yield rate.
2006, 26(5): 434-440.
doi: 10.11883/1001-1455(2006)05-0434-07
Abstract:
Based on the fundamental theories of numerical manifold method (NMM), a criterion of crack initiation and crack growth is introduced into NMM. NMM is used to numerically study the process of two-hole blasting, in which two different initiation conditions are considered. One is simultaneous initiation, the other is 0.1 ms delay initiation. The whole blasting process including crack initiation, crack growth, the formation of fragments and the formation of a blasting crater is simulated. The failure mechanisms of rock under blasting loading and the influences of initiation conditions on that process are analyzed. NMM has proven to be an effective and accurate method for in the study of rock failure from a continuous mass to a discontinuous mass. The results provide further insights and a new method in the research of the related issues.
Based on the fundamental theories of numerical manifold method (NMM), a criterion of crack initiation and crack growth is introduced into NMM. NMM is used to numerically study the process of two-hole blasting, in which two different initiation conditions are considered. One is simultaneous initiation, the other is 0.1 ms delay initiation. The whole blasting process including crack initiation, crack growth, the formation of fragments and the formation of a blasting crater is simulated. The failure mechanisms of rock under blasting loading and the influences of initiation conditions on that process are analyzed. NMM has proven to be an effective and accurate method for in the study of rock failure from a continuous mass to a discontinuous mass. The results provide further insights and a new method in the research of the related issues.
2006, 26(5): 441-447.
doi: 10.11883/1001-1455(2006)05-0441-07
Abstract:
A pressure desensitization degree parameter was proposed to characterize desensitization of emulsion explosive and offer a quantificationally analyzing tool for studying its action mechanism. Pressure desensitization degrees were calculated with parameters, such as peak pressure, its logarithm, shock wave energy and total energy of explosion shock wave, which were respectively produced by emulsion explosive before or after desensitization. Calculated pressure desensitization degrees were similar with different parameters. Calculation with peak pressure was simple and the result calculated with shock wave energy was better. Research results show that pressure desensitization degree calculated with shock wave parameters can reflect the pressure desensitization essence of emulsion explosive.
A pressure desensitization degree parameter was proposed to characterize desensitization of emulsion explosive and offer a quantificationally analyzing tool for studying its action mechanism. Pressure desensitization degrees were calculated with parameters, such as peak pressure, its logarithm, shock wave energy and total energy of explosion shock wave, which were respectively produced by emulsion explosive before or after desensitization. Calculated pressure desensitization degrees were similar with different parameters. Calculation with peak pressure was simple and the result calculated with shock wave energy was better. Research results show that pressure desensitization degree calculated with shock wave parameters can reflect the pressure desensitization essence of emulsion explosive.
2006, 26(5): 448-451.
doi: 10.11883/1001-1455(2006)05-0448-04
Abstract:
A velocity interferometer system for any reflector was used to measure the free surface velocity of steel flyer. The steel flyer was driven by an explosive charge(50 mm50 mm) with two different structure. In one case ,the charge is restricted with a steel tube. In the other, there is no steel tube outside the charge. Experimental results show the restricted charge can accelerate the steel flyer more efficiently. Compared with the naked charge, the restricted charge can increase the velocity of the same steel flyer (50 mm1.5 mm) by 34.8％ and the kinetic energy by 81.7％.
A velocity interferometer system for any reflector was used to measure the free surface velocity of steel flyer. The steel flyer was driven by an explosive charge(50 mm50 mm) with two different structure. In one case ,the charge is restricted with a steel tube. In the other, there is no steel tube outside the charge. Experimental results show the restricted charge can accelerate the steel flyer more efficiently. Compared with the naked charge, the restricted charge can increase the velocity of the same steel flyer (50 mm1.5 mm) by 34.8％ and the kinetic energy by 81.7％.
2006, 26(5): 452-455.
doi: 10.11883/1001-1455(2006)05-0452-04
Abstract:
Based on ANSYS 7.0/LS-DYNA, an analysis is performed of the stress response of a simply-supported plate (3 m3 m), with a hole (0.3 m0.3 m), subjected to positive and negative triangularly-distributed pressures. The dynamic stress concentration factor is determined by using time-distributive function of energy density, and the corresponding procedure is provided. It is shown from the result of calculation that the calculation time and the data-collecting time interval have great effects on the factor, but the negative pressure has an insignificant effect on it.
Based on ANSYS 7.0/LS-DYNA, an analysis is performed of the stress response of a simply-supported plate (3 m3 m), with a hole (0.3 m0.3 m), subjected to positive and negative triangularly-distributed pressures. The dynamic stress concentration factor is determined by using time-distributive function of energy density, and the corresponding procedure is provided. It is shown from the result of calculation that the calculation time and the data-collecting time interval have great effects on the factor, but the negative pressure has an insignificant effect on it.
2006, 26(5): 462-467.
doi: 10.11883/1001-1455(2006)05-0462-06
Abstract:
Propagation of the blast wave in cement sample in the water was simulated. The damage causes of different areas in cement sample were explored by using the method analysizing the blast wave and stress acting on typical cement sample element. Numerical results are in agreement with the experiment.
Propagation of the blast wave in cement sample in the water was simulated. The damage causes of different areas in cement sample were explored by using the method analysizing the blast wave and stress acting on typical cement sample element. Numerical results are in agreement with the experiment.
2006, 26(5): 468-473.
doi: 10.11883/1001-1455(2006)05-0468-06
Abstract:
According to the structural characteristic of the weapon with side chamber, an equivalent model is proposed. Based on the model, two one-dimensional interior ballistic models are developed. Then, second-order TVD algorithm is employed for the computational code for both gas-phase and solid-phase equations. Finally, the model and algorithm are proved to be feasible in comparison with the experimental results of the 12.7mm caliber firing experiments.
According to the structural characteristic of the weapon with side chamber, an equivalent model is proposed. Based on the model, two one-dimensional interior ballistic models are developed. Then, second-order TVD algorithm is employed for the computational code for both gas-phase and solid-phase equations. Finally, the model and algorithm are proved to be feasible in comparison with the experimental results of the 12.7mm caliber firing experiments.
2006, 26(5): 474-480.
doi: 10.11883/1001-1455(2006)05-0474-07
Abstract:
Based on the explicit FEM code LS-DYNA3D and the viscous-spring boundary, the 3D elastic-viscous-plastic dynamic response model composed of explosion cavity, an underground structure, a shock isolation material and geologic backfills were established. The empirical relation was used during the simulation of the explosion cavity. By comparing with the results of the empirical relation of technical manualsTM5-855-1 of the USA Army, it can be see that the proposed model and method are reasonable. The shock isolation effect of the crushable backpacking was also discussed.
Based on the explicit FEM code LS-DYNA3D and the viscous-spring boundary, the 3D elastic-viscous-plastic dynamic response model composed of explosion cavity, an underground structure, a shock isolation material and geologic backfills were established. The empirical relation was used during the simulation of the explosion cavity. By comparing with the results of the empirical relation of technical manualsTM5-855-1 of the USA Army, it can be see that the proposed model and method are reasonable. The shock isolation effect of the crushable backpacking was also discussed.
