The afterburning of TNT and structural constraints in confined spaces significantly amplify the blast load,leading to severe structural damage. This study investigates the mechanisms underlying the enhanced dynamic re...The afterburning of TNT and structural constraints in confined spaces significantly amplify the blast load,leading to severe structural damage. This study investigates the mechanisms underlying the enhanced dynamic response of reinforced concrete blast doors with four-sided restraints in confined space. Explosion tests with TNT charges ranging from 0.15 kg to 0.4 kg were conducted in a confined space,capturing overpressure loads and the dynamic response of the blast door. An internal explosion model incorporating the afterburning effect was developed using LS-DYNA software and validated against experimental data. The results reveal that the TNT afterburning effect amplifies both the initial peak overpressure and the quasi-static overpressure, resulting in increased deformation of the blast door.Within the 0.15-0.4 kg charge range, the initial overpressure peak and quasi-static overpressure increased by an average of 1.79 times and 2.21 times, respectively. Additionally, the afterburning effect enhanced the blast door's deflection by 177%. Compared to open-space scenarios, the cumulative deflection of the blast door due to repeated shock wave impacts is significantly greater in confined spaces. Furthermore, the quasi-static pressure arising from the structural constraints sustains the blast door's deflection at a high level.展开更多
Investigating the blast effects and mechanisms on typical finite-sized obstacles is essential for optimizing defense strategies and designing more robust barriers to deter terrorists and protect critical locations.Thi...Investigating the blast effects and mechanisms on typical finite-sized obstacles is essential for optimizing defense strategies and designing more robust barriers to deter terrorists and protect critical locations.This study investigates the blasting effects and underlying mechanisms of concrete frustums subjected to contact explosions,employing both numerical simulations and field tests.It focuses on the effects of top and side blasting,with particular emphasis on fracture modes,damage patterns,and fragment sizes,as well as the causes of different failure modes and the propagation of stress waves.The study also explores the blasting effects of detonating explosives at varying positions along the side and with different charge amounts.The results show that side-blasting leads to complete fragmentation,with tensile waves playing a significant role in creating extensive damage zones that propagate parallel to the frustum's outer surface,concentrating damage near the surface.During top-blasting,the upper half of the frustum undergoes fragmentation,while the lower half experiences cracking.Tensile waves propagate from the top to the bottom surface,forming larger blocks in regions with lower wave intensity.Three distinct damage zones within the frustum were identified,and a series of mathematical formulas were derived to describe the relationship between the maximum fragment size and charge mass.As the charge mass increased from 1.0 kg to 4.0 kg,the maximum fragment size decreased.Detonation at the center of the frustum's side resulted in the most severe fragmentation,with a 51.8%reduction in fragment size compared to other detonation positions.Finally,four broken modes were classified,each influenced by charge mass and explosive location.This study provides valuable insights for optimizing civil blasting operations and designing protective engineering structures.展开更多
Shockwaves from fuel-air explosive(FAE)cloud explosions may cause significant casualties.The ground overpressure field is usually used to evaluate the damage range of explosion shockwaves.In this paper,a finite elemen...Shockwaves from fuel-air explosive(FAE)cloud explosions may cause significant casualties.The ground overpressure field is usually used to evaluate the damage range of explosion shockwaves.In this paper,a finite element model of multi-sources FAE explosion is established to simulate the process of multiple shockwaves propagation and interaction.The model is verified with the experimental data of a fourfoldsource FAE explosion,with the total fuel mass of 340 kg.Simulation results show that the overpressure fields of multi-sources FAE explosions are different from that of the single-source.In the case of multisources,the overpressure fields are influenced significantly by source scattering distance and source number.Subsequently,damage ranges of overpressure under three different levels are calculated.Within a suitable source scattering distance,the damage range of multi-sources situation is greater than that of the single-source,under the same amount of total fuel mass.This research provides a basis for personnel shockwave protection from multi-sources FAE explosion.展开更多
Reinforced concrete(RC) columns are widely used as supporting structures for high-piled wharfs.The study of damage model of a RC column due to underwater explosion is a critical issue to assess the wharfs antiknock se...Reinforced concrete(RC) columns are widely used as supporting structures for high-piled wharfs.The study of damage model of a RC column due to underwater explosion is a critical issue to assess the wharfs antiknock security.In this study,the dynamic response and damage model of circular RC columns subjected to underwater explosions were investigated by means of scaled-down experiment models.Experiments were carried out in a 10.0 m diameter tank with the water depth of 2.25 m,under different explosive quantities(0.025 kg-1.6 kg),stand-off distances(0.0 m-7.0 m),and detonation depths(0.25 m-2.0 m).The shock wave load and dynamic response of experiment models were measured by configuring sensors of pressure,acceleration,strain,and displacement.Then,the load distribution characteristics,time history of test data,and damage models related to present conditions were obtained and discussed.Three damage models,including bending failure,bending-shear failure and punching failure,were identified.In addition,the experie nce model of shock wave loads on the surface of a RC column was proposed for engineering application.展开更多
Five types of polyurea elastomers were synthesized by changing the isocyanate component and the mechanical properties of polyurea materials were measured. Fiber-reinforced cement boards(FRCB)strengthened by polyurea w...Five types of polyurea elastomers were synthesized by changing the isocyanate component and the mechanical properties of polyurea materials were measured. Fiber-reinforced cement boards(FRCB)strengthened by polyurea with different formulations were processed, and a series of experiments were carried out on the specimens with gas explosion devices. The results showed that the conventional mechanical properties of different types of polyureas had their own advantages. Based on the gas explosion overpressure criterion, the blast resistances of reinforced plates were quantitatively evaluated,and the best polyurea was selected to guide the formulation design. The three typical failure modes of polyurea-reinforced FRCBs were flexural, shear, and flexural-shear failure. Dynamic thermodynamics and shock wave spectral analysis revealed that the polyurea did not undergo a glass transition in the gas explosion tests but retained its elastic properties, allowing it to effectively wrap the fragments formed by the brittle substrates.展开更多
Over the past century,the safety of dams has gradually attracted attention from all parties.Research on the dynamic response and damage evolution of dams under extreme loads is the basis of dam safety issues.In recent...Over the past century,the safety of dams has gradually attracted attention from all parties.Research on the dynamic response and damage evolution of dams under extreme loads is the basis of dam safety issues.In recent decades,scholars have studied the responses of dams under earthquake loads,but there is still much room for improvement in experimental and theoretical research on small probability loads such as explosions.In this paper,a 50-m-high concrete gravity dam is used as a prototype dam,and a water explosion model test of a 2.5-m-high concrete gravity dam is designed.The water pressure and the acceleration response of the dam body in the test are analysed.The pressure characteristics and dynamic response of the dam body are assessed.Taking the dam damage test as an example,a numerical model of concrete gravity dam damage is established,and the damage evolution of the dam body is analysed.By combining experiments and numerical simulations,the damage characteristics of the dam body under the action of different charge water explosions are clarified.The integrity of the dam body is well maintained under the action of a small-quantity water explosion,and the dynamic response of the dam body is mainly caused by the shock wave.Both the shock wave and the bubble pulsation cause the dam body to accelerate,and the peak acceleration of the dam body under the action of the bubble pulsation is only one percent of the peak acceleration of the dam body under the action of the shock wave.When subjected to explosions in large quantities of water,the dam body is seriously damaged.Under the action of a shock wave,the dam body produces a secondary acceleration response,which is generated by an internal interaction after the dam body is damaged.The damage evolution process of the dam body under the action of a large-scale water explosion is analysed,and it is found that the shock wave pressure of the water explosion causes local damage to the dam body facing the explosion.After the peak value of the shock wave,the impulse continues to act on the dam body,causing cumulative damage and damage inside the dam body.展开更多
It is important to investigate the dynamic behaviors of deep rocks near explosion cavity to reveal the mechanisms of deformations and fractures. Some improvements are carried out for Grigorian model with focuses on th...It is important to investigate the dynamic behaviors of deep rocks near explosion cavity to reveal the mechanisms of deformations and fractures. Some improvements are carried out for Grigorian model with focuses on the dilation effects and the relaxation effects of deep rocks, and the high pressure equations of states with Mie-Grüneisen form are also established. Numerical calculations of free field parameters for deep underground explosions are carried out based on the user subroutines which are compiled by means of the secondary development functions of LS-DYNA9703 D software. The histories of radial stress, radial velocity and radial displacement of rock particles are obtained, and the calculation results are compared with those of U.S. Hardhat nuclear test. It is indicated that the dynamic responses of free field for deep underground explosions are well simulated based on improved Grigorian model, and the calculation results are in good agreement with the data of U.S. Hardhat nuclear test. The peak values of particle velocities are consistent with those of test, but the waveform widths and the rising times are obviously greater than those without dilation effects. The attenuation rates of particle velocities are greater than the calculation results with classic plastic model, and they are consistent with the results of Hardhat nuclear test. The attenuation behaviors and the rising times of stress waves are well shown by introducing dilation effects and relaxation effects into the calculation model. Therefore, the defects of Grigorian model are avoided. It is also indicated that the initial stress has obvious influences on the waveforms of radial stress and the radial displacements of rock particles.展开更多
Urban growth has promoted the use of underground spaces,where explosion accidents can be catastrophic.In this study,we investigated the effect of placing flexible construction in front of rigid obstacles on methane ex...Urban growth has promoted the use of underground spaces,where explosion accidents can be catastrophic.In this study,we investigated the effect of placing flexible construction in front of rigid obstacles on methane explosion protection by using an experimental platform and adjusting the blockage rate and spacing of the obstacles.It aims to reduce the risk of gas explosions in urban underground spaces.The results of the study show that the flame propagation peak speed and peak overpressure are reduced with the decrease in the blocking rate of the flexible obstacle when the blocking rate of the flexible obstacle is less than or equal to the blocking rate of the rigid obstacle,with the decrease in the spacing,the better the protection effect of the methane explosion.When the blockage rate of the flexible obstacle is greater than the blockage rate of the rigid obstacle and spacing is less than the height of the flexible obstacle,rigid and flexible obstacles are connected as a whole,increasing the strength of the explosion.This study can provide a theoretical basis and scientific guidance for optimizing rigid and flexible object hybrid layouts and methane explosion protection technology in urban underground spaces.展开更多
RBOE is a new type of DNAN-based high-energy melt-cast mixed explosive,whose safety under thermal stimulation is significantly affected by heating conditions and venting area of the warhead.Based on the thermal decomp...RBOE is a new type of DNAN-based high-energy melt-cast mixed explosive,whose safety under thermal stimulation is significantly affected by heating conditions and venting area of the warhead.Based on the thermal decomposition reaction characteristics and combustion characteristics of each component of RBOE explosive,the cook-off calculation models of RBOE warhead before and after ignition were established.In addition,closed and vented warheads were designed,as well as fast and slow cook-off test devices.The cook-off characteristics and thermal safety venting area of RBOE warhead were extensively studied.The results showed that the closed RBOE warhead underwent deflagration reaction under both slow and fast cook-off conditions.The calculation result of the shell wall temperature before slow cookoff ignition response of the warhead was 454.06 K,with an error of+1.75%compared to the test result of462.15 K,and the temperature rise rate calculated was in good agreement with the test.The calculated ignition time of RBOE warhead under fast cook-off was 161 s,with an error of+8.8%compared to the test result of 148 s,which verified the accuracy of cook-off model of RBOE warhead before ignition.According to the cook-off calculation model of the warhead after ignition and cook-off test of the vented warhead,it was determined that the thermal safety venting area was 1124.61 mm^(2)for fast cook-off and 530.66 mm~2 for slow cook-off,effectively preventing the reaction of warhead above combustion.Therefore,this study provides a scientific basis for the thermal safety design and evaluation of insensitive warheads.展开更多
While the moisture content of soil affects significantly the blast impulse of shallow buried explosives,the role of surface-covering water(SCW)on soil in such blast impulse remains elusive.A combined experimental and ...While the moisture content of soil affects significantly the blast impulse of shallow buried explosives,the role of surface-covering water(SCW)on soil in such blast impulse remains elusive.A combined experimental and numerical study has been carried out to characterize the effect of SCW on transferred impulse and loading magnitude of shallow buried explosives.Firstly,blast tests of shallow buried explosives were conducted,with and without the SCW,to quantitatively assess the blast loading impulse.Subsequently,finite element(FE)simulations were performed and validated against experimental measurement,with good agreement achieved.The validated FE model was then employed to predict the dynamic response of a fully-clamped metallic circular target,subjected to the explosive impact of shallow buried explosives with SCW,and explore the corresponding physical mechanisms.It was demonstrated that shallow buried explosives in saturated soil generate a greater impulse transferred towards the target relative to those in dry soil.The deformation displacement of the target plate is doubled.Increasing the height of SCW results in enhanced center peak deflection of the loaded target,accompanied by subsequent fall,due to the variation of deformation pattern of the loaded target from concentrated load to uniform load.Meanwhile,the presence of SCW increases the blast impulse transferred towards the target by three times.In addition,there exists a threshold value of the burial depth that maximizes the impact impulse.This threshold exhibits a strong sensitivity to SCW height,decreasing with increasing SCW height.An empirical formula for predicting threshold has been provided.Similar conclusions can be drawn for different explosive masses.The results provide technical guidance on blast loading intensity and its spatial distribution considering shallow buried explosives in coast-land battlefields,which can ultimately contribute to better protective designs.展开更多
Due to the presence of nitro groups, the dust generated during the production and utilization of energetic materials may potentially lead to dust explosion even under low-oxygen or anaerobic conditions.Considering the...Due to the presence of nitro groups, the dust generated during the production and utilization of energetic materials may potentially lead to dust explosion even under low-oxygen or anaerobic conditions.Considering the high energy density of energetic materials, dust explosion can cause serious production safety accidents. Therefore, it is necessary to understand the dust explosion characteristics of energetic materials and the mechanism of dust explosion. According to the literature review, among various influencing factors, the physical and chemical properties of dust are the decisive factors affecting the explosion characteristics of dust. In addition to experimental studies, numerical simulation is another important tool. However, it is subjected to certain limitations. Moreover, it is essential but challenging to fully understand the underlying mechanism. In addition, given the safety hazards posed by dust explosion, explosion suppression has attracted extensive attention for research. Depending on the medium used, there are different forms of suppression, including powder explosion suppression, water spray explosion suppression, inert gas explosion suppression, porous material explosion suppression, and vacuum chamber explosion suppression. As for the selection of explosion suppression agent, consideration must be given to the characteristics of the material. Furthermore, the above research has laid a foundation for discussing the future progress in studying dust explosion of energetic materials, with nano dust and the constraints of existing technology as the focal point.展开更多
The gas explosion in residential building has always been a highly concerned problem.Explosions in homogeneous mixtures have been extensively studied.However,mixtures are often inhomogeneous in the practical scenarios...The gas explosion in residential building has always been a highly concerned problem.Explosions in homogeneous mixtures have been extensively studied.However,mixtures are often inhomogeneous in the practical scenarios due to the differences in the densities of methane and air.In order to investigate the effects of gas explosions in inhomogeneous mixtures,experimental studies involving gas leakage and explosion are conducted in a full-scale residential building to reproduce the process of gas explosion.By fitting the dimensionless buoyancy as a function of dimensionless height and dimensionless time,a distribution model of gas in large-scale spaces is established,and the mechanism of inhomogeneous distribution of methane is also be revealed.Furthermore,the stratified reconstruction method(SRM)is introduced for efficiently setting up inhomogeneous concentration fields in FLACS.The simulation results highlight that for the internal overpressure,the distribution of methane has no effect on the first overpressure peak(ΔP1),while it significantly influences the subsequent overpressure peak(ΔP2),and the maximum difference between the overpressure of homogeneous and inhomogeneous distribution is174.3%.Moreover,the initial concentration distribution also has a certain impact on the external overpressure.展开更多
RDX/Al mixtures are widely utilized in energetic materials,yet their hybrid dust generated during production and application poses potential explosion hazards.Moreover,the synergistic explosion mechanisms remain poorl...RDX/Al mixtures are widely utilized in energetic materials,yet their hybrid dust generated during production and application poses potential explosion hazards.Moreover,the synergistic explosion mechanisms remain poorly understood,particularly at varying dust concentrations.This study systematically investigates the effects of different aluminum powder mass percentages and dust concentrations(300 g/m^(3),600 g/m^(3),900 g/m^(3))on RDX dust explosion severity,flame propagation behavior,and gaseous products.The results indicate that the maximum explosion pressure peaks at 35%RDX,65%RDX,and 80%RDX at 300 g/m^(3),600 g/m^(3),and 900 g/m^(3),respectively.Concurrently,the time for the flame to propagate to the wall(t1)reaches minimum values of 34.8 ms,25.66 ms,and 23.93 ms.The maximum rate of pressure rise is observed for pure RDX at 900 g/m^(3).Aluminum powder enhances flame propagation velocity and combustion duration,as validated by the flame propagation system.Overall,the concentrations of carbon oxides(CO+CO_(2))decrease significantly with increasing aluminum mass percentage.At 20%RDX,the concentrations decreased by 51.64%,72.31%,and 79.55%compared to pure RDX at 300 g/m^(3),600 g/m^(3),and 900 g/m^(3),respectively.Notably,N_(2)O concentration only at 300 g/m^(3)showed such a trend.It rises first and then falls at 35%RDX at 600 g/m^(3)and 900 g/m^(3).These findings elucidate the synergistic explosion mechanisms and provide critical guidelines for safe production and handling.展开更多
This study represents an important step forward in the domain of additive manufacturing of energetic materials.It presents the successful formulation and fabrication by 3D printing of gun propellants using Fused Depos...This study represents an important step forward in the domain of additive manufacturing of energetic materials.It presents the successful formulation and fabrication by 3D printing of gun propellants using Fused Deposition Modeling(FDM)technology,highlighting the immense potential of this innovative approach.The use of FDM additive manufacturing technology to print gun propellants is a significant advancement due to its novel application in this field,which has not been previously reported.Through this study,the potential of FDM 3D-printing in the production of high-performance energetic composites is demonstrated,and also a new standard for manufacturability in this field can be established.The thermoplastic composites developed in this study are characterized by a notably high energetic solids content,comprising 70%hexogen(RDX)and 10%nitrocellulose(NC),which surpasses the conventional limit of 60%energetic solids typically achieved in stereolithography and light-curing 3D printing methods.The primary objective of the study was to optimize the formulation,enhance performance,and establish an equilibrium between printability and propellant efficacy.Among the three energetic for-mulations developed for 3D printing feedstock,only two were suitable for printing via the FDM tech-nique.Notably,the formulation consisting of 70%RDX,10%NC,and 20%polycaprolactone(PCL)emerged as the most advantageous option for gun propellants,owing to its exceptional processability,ease of printability,and high energetic performance.展开更多
The internal and external flow fields during vented explosions of methane were characterized through numerical simulation,and the capability of numerical simulation thereof was validated by previous experimental data ...The internal and external flow fields during vented explosions of methane were characterized through numerical simulation,and the capability of numerical simulation thereof was validated by previous experimental data at three ignition positions.The venting mechanism was revealed by the simulated concentration distribution,temperature profile,and airflow velocity.The results show rear ignition results in the external methane mass distribution taking the form of"mushroom"and columnar flames in the external space,which can be expressed as a third-order polynomial relationship with distance;central ignition forms a relationship of the form y=AxB.Front ignition causes the temperature to show a tendency to repeated oscillations(rising,falling,and rising).Central ignition generates the maximum vented airflow velocity(V_(max)=320 m/s)upon vent opening.The results indicate that it is acceptable to apply numerical simulation of methane explosions in practice.展开更多
This study investigates the paradoxical detonation behavior of TKX-50,a nitrogen-rich energetic material,exhibiting higher detonation velocities but lower metal acceleration ability compared to HMX.Through experimenta...This study investigates the paradoxical detonation behavior of TKX-50,a nitrogen-rich energetic material,exhibiting higher detonation velocities but lower metal acceleration ability compared to HMX.Through experimental measurements and theoretical calculations,we propose a novel three-factor competition mechanism to explain this phenomenon.TKX-50-based PBX formulations achieved detonation velocities up to 9100 m/s,surpassing HMX-based counterparts.However,cylinder expansion tests revealed a 15%reduction in metal acceleration ability.Thermochemical measurements showed lower detonation heat for TKX-50(4900 J/g)versus HMX(5645 J/g).Our mechanism involves:(1)compositional effects prevailing at high pressures;(2)Energy release becoming essential as pressure drops;(3)Pressure-dependent product composition evolution functioning at low pressure.VLW code calculations unveiled a"crossover"in Hugoniot curves,lending support to this mechanism.This study furnishes a new framework for comprehending the performance of nitrogen-rich energetic materials,with significant implications for the design and optimization of future high-energy density materials.展开更多
The desensitization of nitramine explosives while maintaining energetic performance is challenging.A highly efficient desensitizer is the key to solving the antinomy.This study focuses on using porous organic cages(PO...The desensitization of nitramine explosives while maintaining energetic performance is challenging.A highly efficient desensitizer is the key to solving the antinomy.This study focuses on using porous organic cages(POCs),specifically CC3 and RCC3,to desensitize RDX.By coating 0.1 wt%–5 wt%of POCs on RDX particles,a series of composite energetic materials were prepared.Characterization results show that POCs change the surface morphology of RDX,and there are interfacial interactions between them.The RDX@POCs composites exhibit enhanced stabilities in terms of heat,impact,friction,and electrostatic spark.For the RDX@RCC3-5%composite,the impact sensitivity(E_(IS)),friction sensitivity(E_(FS)),and electrostatic sensitivity(EES)were significantly reduced by 66.7%,68.8%,and 56.5%,respectively,while the detonation velocity decreased by merely 3.1%.These findings indicate that POCs,especially RCC3,are promising desensitizers for nitramine explosives,and their desensitization mechanisms likely involve barrier and buffering effects.The distinct desensitization behavior of RDX@RCC3 highlights the effectiveness of POCs in reducing the sensitivity of RDX without significantly compromising its energetic properties.展开更多
With different structural forms of ventilation pipes have various attenuation effects on incident shock waves while meeting ventilation requirements.The attenuation mechanism and the propagation law of shock waves in ...With different structural forms of ventilation pipes have various attenuation effects on incident shock waves while meeting ventilation requirements.The attenuation mechanism and the propagation law of shock waves in ventilation pipes of different structures are investigated by experiments and numerical simulations.Furthermore,for the same structure,the effects of peak pressure and positive pressure time on the attenuation rate are discussed.It is found that the attenuation rate increases with the incident shock wave pressure,and the shock wave attenuation rate tends to reach its limiting value k for the same structure and reasonably short positive pressure time.Under the same conditions,the attenuation rate is calculated using the pressure of the shock wave as follows:diffusion chamber pipe,branch pipe and selfconsumption pipe;the attenuation rate per unit volume is calculated as follows:self-consumption pipe,branch pipe and diffusion chamber pipe.In addition,an easy method is provided to calculate the attenuation rate of the shock wave in single and multi-stage ventilation pipes.Corresponding parameters are provided for various structures,and the margin of error between the formulae and experimental results is within 10%,which is significant for engineering applications.展开更多
Detonation performance is crucial for evaluating the power of high explosives(HEs),and the equation of state(EOS)that accurately describes the high-temperature,high-pressure,and high-temperature,medium-pressure states...Detonation performance is crucial for evaluating the power of high explosives(HEs),and the equation of state(EOS)that accurately describes the high-temperature,high-pressure,and high-temperature,medium-pressure states of detonation products is key to assessing the damage efficiency of these energetic materials.This article examines the limitations of the VLW EOS in representing the thermodynamic states of explosive detonation gas products under high-temperature and medium-to high-pressure conditions.A new gas EOS for detonation products,called VHL(Virial-Han-Long),is proposed.The accuracy of VHL in describing gas states under high-temperature and medium-to high-pressure conditions is verified,and its performance in evaluating explosive detonation and working capabilities is explored.The results demonstrate that VHL exhibits high precision in calculating detonation performance.Subsequently,the detonation performance of three new HEs(ICM-101,ONC,and TNAZ)was calculated and compared to traditional HEs(TATB,CL-20,and HMX).The results indicate that ONC has superior detonation performance compared to the other explosives,while ICM-101 shows a detonation velocity similar to CL-20 but with slightly lower detonation pressure.The detonation characteristics of TNAZ are comparable to those of the standard HE HMX.From the perspective of products,considering the comprehensive work performance(mechanical work and detonation heat),both ONC and ICM-101demonstrate relatively superior performance.展开更多
The concept of TNT(Trinitrotoluene,C_7H_5N_3O_6)equivalence is often invoked to evaluate the performance and predict the explosion parameters of different types of explosives.However,due to its low prediction accuracy...The concept of TNT(Trinitrotoluene,C_7H_5N_3O_6)equivalence is often invoked to evaluate the performance and predict the explosion parameters of different types of explosives.However,due to its low prediction accuracy and limited application range,the use of TNT equivalence for predicting explosion parameters in a confined space is rare.Compared with explosions in free fields,the process of explosive energy release in a confined space is closely related to various factors such as oxygen balance,combustible components content,and surrounding oxygen content.Studies have shown that in a confined space,negative oxygen balance explosives react with surrounding oxygen during afterburning,resulting in additional energy release and enhanced blast effects.The mechanism of energy release during afterburning is highly complex,making it challenging to determine the TNT equivalence for blast effects in a confined space.Therefore,this remains an active area of research.In this study,internal blast experiments were conducted using TNT and three other explosives under both air and N_2(Nitrogen)conditions to obtain explosion parameters including blast wave overpressure,quasi-static pressure,and temperature.The influences of oxygen balance and external oxygen content on energy release are analyzed.The author proposes principles for determining TNT equivalence for internal explosions while verifying the accuracy of obtained blast parameters through calculations based on TNT equivalence.These findings can serve as references for predicting blast performance.展开更多
基金financially supported by the National Natural Science Foundation of China (Grant No. 52278504)the Natural Science Foundation of Jiangsu Province (Grant No. BK20220141)。
文摘The afterburning of TNT and structural constraints in confined spaces significantly amplify the blast load,leading to severe structural damage. This study investigates the mechanisms underlying the enhanced dynamic response of reinforced concrete blast doors with four-sided restraints in confined space. Explosion tests with TNT charges ranging from 0.15 kg to 0.4 kg were conducted in a confined space,capturing overpressure loads and the dynamic response of the blast door. An internal explosion model incorporating the afterburning effect was developed using LS-DYNA software and validated against experimental data. The results reveal that the TNT afterburning effect amplifies both the initial peak overpressure and the quasi-static overpressure, resulting in increased deformation of the blast door.Within the 0.15-0.4 kg charge range, the initial overpressure peak and quasi-static overpressure increased by an average of 1.79 times and 2.21 times, respectively. Additionally, the afterburning effect enhanced the blast door's deflection by 177%. Compared to open-space scenarios, the cumulative deflection of the blast door due to repeated shock wave impacts is significantly greater in confined spaces. Furthermore, the quasi-static pressure arising from the structural constraints sustains the blast door's deflection at a high level.
基金the support provided by the Technology Innovation Project (Grant No. KYGYZB002201) for the research work
文摘Investigating the blast effects and mechanisms on typical finite-sized obstacles is essential for optimizing defense strategies and designing more robust barriers to deter terrorists and protect critical locations.This study investigates the blasting effects and underlying mechanisms of concrete frustums subjected to contact explosions,employing both numerical simulations and field tests.It focuses on the effects of top and side blasting,with particular emphasis on fracture modes,damage patterns,and fragment sizes,as well as the causes of different failure modes and the propagation of stress waves.The study also explores the blasting effects of detonating explosives at varying positions along the side and with different charge amounts.The results show that side-blasting leads to complete fragmentation,with tensile waves playing a significant role in creating extensive damage zones that propagate parallel to the frustum's outer surface,concentrating damage near the surface.During top-blasting,the upper half of the frustum undergoes fragmentation,while the lower half experiences cracking.Tensile waves propagate from the top to the bottom surface,forming larger blocks in regions with lower wave intensity.Three distinct damage zones within the frustum were identified,and a series of mathematical formulas were derived to describe the relationship between the maximum fragment size and charge mass.As the charge mass increased from 1.0 kg to 4.0 kg,the maximum fragment size decreased.Detonation at the center of the frustum's side resulted in the most severe fragmentation,with a 51.8%reduction in fragment size compared to other detonation positions.Finally,four broken modes were classified,each influenced by charge mass and explosive location.This study provides valuable insights for optimizing civil blasting operations and designing protective engineering structures.
基金The authors would like to acknowledge the China Postdoctoral Science Foundation(Grant No.2019M660488)to provide fund for this work.
文摘Shockwaves from fuel-air explosive(FAE)cloud explosions may cause significant casualties.The ground overpressure field is usually used to evaluate the damage range of explosion shockwaves.In this paper,a finite element model of multi-sources FAE explosion is established to simulate the process of multiple shockwaves propagation and interaction.The model is verified with the experimental data of a fourfoldsource FAE explosion,with the total fuel mass of 340 kg.Simulation results show that the overpressure fields of multi-sources FAE explosions are different from that of the single-source.In the case of multisources,the overpressure fields are influenced significantly by source scattering distance and source number.Subsequently,damage ranges of overpressure under three different levels are calculated.Within a suitable source scattering distance,the damage range of multi-sources situation is greater than that of the single-source,under the same amount of total fuel mass.This research provides a basis for personnel shockwave protection from multi-sources FAE explosion.
基金funded by the National Natural Science Foundation of China(Grant Nos.51578543)。
文摘Reinforced concrete(RC) columns are widely used as supporting structures for high-piled wharfs.The study of damage model of a RC column due to underwater explosion is a critical issue to assess the wharfs antiknock security.In this study,the dynamic response and damage model of circular RC columns subjected to underwater explosions were investigated by means of scaled-down experiment models.Experiments were carried out in a 10.0 m diameter tank with the water depth of 2.25 m,under different explosive quantities(0.025 kg-1.6 kg),stand-off distances(0.0 m-7.0 m),and detonation depths(0.25 m-2.0 m).The shock wave load and dynamic response of experiment models were measured by configuring sensors of pressure,acceleration,strain,and displacement.Then,the load distribution characteristics,time history of test data,and damage models related to present conditions were obtained and discussed.Three damage models,including bending failure,bending-shear failure and punching failure,were identified.In addition,the experie nce model of shock wave loads on the surface of a RC column was proposed for engineering application.
基金funded by National Natural Science Foundation of China(No.12002392).
文摘Five types of polyurea elastomers were synthesized by changing the isocyanate component and the mechanical properties of polyurea materials were measured. Fiber-reinforced cement boards(FRCB)strengthened by polyurea with different formulations were processed, and a series of experiments were carried out on the specimens with gas explosion devices. The results showed that the conventional mechanical properties of different types of polyureas had their own advantages. Based on the gas explosion overpressure criterion, the blast resistances of reinforced plates were quantitatively evaluated,and the best polyurea was selected to guide the formulation design. The three typical failure modes of polyurea-reinforced FRCBs were flexural, shear, and flexural-shear failure. Dynamic thermodynamics and shock wave spectral analysis revealed that the polyurea did not undergo a glass transition in the gas explosion tests but retained its elastic properties, allowing it to effectively wrap the fragments formed by the brittle substrates.
文摘Over the past century,the safety of dams has gradually attracted attention from all parties.Research on the dynamic response and damage evolution of dams under extreme loads is the basis of dam safety issues.In recent decades,scholars have studied the responses of dams under earthquake loads,but there is still much room for improvement in experimental and theoretical research on small probability loads such as explosions.In this paper,a 50-m-high concrete gravity dam is used as a prototype dam,and a water explosion model test of a 2.5-m-high concrete gravity dam is designed.The water pressure and the acceleration response of the dam body in the test are analysed.The pressure characteristics and dynamic response of the dam body are assessed.Taking the dam damage test as an example,a numerical model of concrete gravity dam damage is established,and the damage evolution of the dam body is analysed.By combining experiments and numerical simulations,the damage characteristics of the dam body under the action of different charge water explosions are clarified.The integrity of the dam body is well maintained under the action of a small-quantity water explosion,and the dynamic response of the dam body is mainly caused by the shock wave.Both the shock wave and the bubble pulsation cause the dam body to accelerate,and the peak acceleration of the dam body under the action of the bubble pulsation is only one percent of the peak acceleration of the dam body under the action of the shock wave.When subjected to explosions in large quantities of water,the dam body is seriously damaged.Under the action of a shock wave,the dam body produces a secondary acceleration response,which is generated by an internal interaction after the dam body is damaged.The damage evolution process of the dam body under the action of a large-scale water explosion is analysed,and it is found that the shock wave pressure of the water explosion causes local damage to the dam body facing the explosion.After the peak value of the shock wave,the impulse continues to act on the dam body,causing cumulative damage and damage inside the dam body.
基金Project(51378498)supported by the National Natural Science Foundation of ChinaProject(BK20141066)supported the Natural Science Foundation of Jiangsu Province,China+1 种基金Project(SKLGDUEK1208)supported by State Key Laboratory for Geo Mechanics and Deep Underground Engineering(China University of Mining & Technology),ChinaProject(DPMEIKF201301)supported by State Key Laboratory of Disaster Prevention & Mitigation of Explosion & Impact(PLA University of Science and Technology),China
文摘It is important to investigate the dynamic behaviors of deep rocks near explosion cavity to reveal the mechanisms of deformations and fractures. Some improvements are carried out for Grigorian model with focuses on the dilation effects and the relaxation effects of deep rocks, and the high pressure equations of states with Mie-Grüneisen form are also established. Numerical calculations of free field parameters for deep underground explosions are carried out based on the user subroutines which are compiled by means of the secondary development functions of LS-DYNA9703 D software. The histories of radial stress, radial velocity and radial displacement of rock particles are obtained, and the calculation results are compared with those of U.S. Hardhat nuclear test. It is indicated that the dynamic responses of free field for deep underground explosions are well simulated based on improved Grigorian model, and the calculation results are in good agreement with the data of U.S. Hardhat nuclear test. The peak values of particle velocities are consistent with those of test, but the waveform widths and the rising times are obviously greater than those without dilation effects. The attenuation rates of particle velocities are greater than the calculation results with classic plastic model, and they are consistent with the results of Hardhat nuclear test. The attenuation behaviors and the rising times of stress waves are well shown by introducing dilation effects and relaxation effects into the calculation model. Therefore, the defects of Grigorian model are avoided. It is also indicated that the initial stress has obvious influences on the waveforms of radial stress and the radial displacements of rock particles.
基金supported by the National Natural Science Foundation of China(Grant No.52274177)Science and Technology Research Program of Chongqing Municipal Education Commission(Grant No.KJZD-K202401501)+1 种基金Chongqing Graduate Student Research Innovation Program(Grant No.CYS240800)The Science and Technology Innovation Project for Graduate Students of Chongqing University of Science and Technology(Grant No.YKJCX2420702).
文摘Urban growth has promoted the use of underground spaces,where explosion accidents can be catastrophic.In this study,we investigated the effect of placing flexible construction in front of rigid obstacles on methane explosion protection by using an experimental platform and adjusting the blockage rate and spacing of the obstacles.It aims to reduce the risk of gas explosions in urban underground spaces.The results of the study show that the flame propagation peak speed and peak overpressure are reduced with the decrease in the blocking rate of the flexible obstacle when the blocking rate of the flexible obstacle is less than or equal to the blocking rate of the rigid obstacle,with the decrease in the spacing,the better the protection effect of the methane explosion.When the blockage rate of the flexible obstacle is greater than the blockage rate of the rigid obstacle and spacing is less than the height of the flexible obstacle,rigid and flexible obstacles are connected as a whole,increasing the strength of the explosion.This study can provide a theoretical basis and scientific guidance for optimizing rigid and flexible object hybrid layouts and methane explosion protection technology in urban underground spaces.
基金National Natural Science Foundation of china(Grant No.12402468)。
文摘RBOE is a new type of DNAN-based high-energy melt-cast mixed explosive,whose safety under thermal stimulation is significantly affected by heating conditions and venting area of the warhead.Based on the thermal decomposition reaction characteristics and combustion characteristics of each component of RBOE explosive,the cook-off calculation models of RBOE warhead before and after ignition were established.In addition,closed and vented warheads were designed,as well as fast and slow cook-off test devices.The cook-off characteristics and thermal safety venting area of RBOE warhead were extensively studied.The results showed that the closed RBOE warhead underwent deflagration reaction under both slow and fast cook-off conditions.The calculation result of the shell wall temperature before slow cookoff ignition response of the warhead was 454.06 K,with an error of+1.75%compared to the test result of462.15 K,and the temperature rise rate calculated was in good agreement with the test.The calculated ignition time of RBOE warhead under fast cook-off was 161 s,with an error of+8.8%compared to the test result of 148 s,which verified the accuracy of cook-off model of RBOE warhead before ignition.According to the cook-off calculation model of the warhead after ignition and cook-off test of the vented warhead,it was determined that the thermal safety venting area was 1124.61 mm^(2)for fast cook-off and 530.66 mm~2 for slow cook-off,effectively preventing the reaction of warhead above combustion.Therefore,this study provides a scientific basis for the thermal safety design and evaluation of insensitive warheads.
基金supported by the National Natural Science Foundation of China(Grant Nos.12002156,11972185,12372136)Research Fund of State Key Laboratory of Mechanics and Control for Aerospace Structures(Grant No.MCMS-I-0222K01)。
文摘While the moisture content of soil affects significantly the blast impulse of shallow buried explosives,the role of surface-covering water(SCW)on soil in such blast impulse remains elusive.A combined experimental and numerical study has been carried out to characterize the effect of SCW on transferred impulse and loading magnitude of shallow buried explosives.Firstly,blast tests of shallow buried explosives were conducted,with and without the SCW,to quantitatively assess the blast loading impulse.Subsequently,finite element(FE)simulations were performed and validated against experimental measurement,with good agreement achieved.The validated FE model was then employed to predict the dynamic response of a fully-clamped metallic circular target,subjected to the explosive impact of shallow buried explosives with SCW,and explore the corresponding physical mechanisms.It was demonstrated that shallow buried explosives in saturated soil generate a greater impulse transferred towards the target relative to those in dry soil.The deformation displacement of the target plate is doubled.Increasing the height of SCW results in enhanced center peak deflection of the loaded target,accompanied by subsequent fall,due to the variation of deformation pattern of the loaded target from concentrated load to uniform load.Meanwhile,the presence of SCW increases the blast impulse transferred towards the target by three times.In addition,there exists a threshold value of the burial depth that maximizes the impact impulse.This threshold exhibits a strong sensitivity to SCW height,decreasing with increasing SCW height.An empirical formula for predicting threshold has been provided.Similar conclusions can be drawn for different explosive masses.The results provide technical guidance on blast loading intensity and its spatial distribution considering shallow buried explosives in coast-land battlefields,which can ultimately contribute to better protective designs.
基金the financial support of the Shanxi Fire & Explosion-Proofing Safety Engineering and Technology Research Center, North University of China。
文摘Due to the presence of nitro groups, the dust generated during the production and utilization of energetic materials may potentially lead to dust explosion even under low-oxygen or anaerobic conditions.Considering the high energy density of energetic materials, dust explosion can cause serious production safety accidents. Therefore, it is necessary to understand the dust explosion characteristics of energetic materials and the mechanism of dust explosion. According to the literature review, among various influencing factors, the physical and chemical properties of dust are the decisive factors affecting the explosion characteristics of dust. In addition to experimental studies, numerical simulation is another important tool. However, it is subjected to certain limitations. Moreover, it is essential but challenging to fully understand the underlying mechanism. In addition, given the safety hazards posed by dust explosion, explosion suppression has attracted extensive attention for research. Depending on the medium used, there are different forms of suppression, including powder explosion suppression, water spray explosion suppression, inert gas explosion suppression, porous material explosion suppression, and vacuum chamber explosion suppression. As for the selection of explosion suppression agent, consideration must be given to the characteristics of the material. Furthermore, the above research has laid a foundation for discussing the future progress in studying dust explosion of energetic materials, with nano dust and the constraints of existing technology as the focal point.
基金the financial support from National Natural Science Foundation of China(Grant No.52378488)Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.KYCX22_0222)。
文摘The gas explosion in residential building has always been a highly concerned problem.Explosions in homogeneous mixtures have been extensively studied.However,mixtures are often inhomogeneous in the practical scenarios due to the differences in the densities of methane and air.In order to investigate the effects of gas explosions in inhomogeneous mixtures,experimental studies involving gas leakage and explosion are conducted in a full-scale residential building to reproduce the process of gas explosion.By fitting the dimensionless buoyancy as a function of dimensionless height and dimensionless time,a distribution model of gas in large-scale spaces is established,and the mechanism of inhomogeneous distribution of methane is also be revealed.Furthermore,the stratified reconstruction method(SRM)is introduced for efficiently setting up inhomogeneous concentration fields in FLACS.The simulation results highlight that for the internal overpressure,the distribution of methane has no effect on the first overpressure peak(ΔP1),while it significantly influences the subsequent overpressure peak(ΔP2),and the maximum difference between the overpressure of homogeneous and inhomogeneous distribution is174.3%.Moreover,the initial concentration distribution also has a certain impact on the external overpressure.
基金the financial support of the Shanxi Fire&Explosion-Proofing Safety Engineering and Technology Research Center,North University of China。
文摘RDX/Al mixtures are widely utilized in energetic materials,yet their hybrid dust generated during production and application poses potential explosion hazards.Moreover,the synergistic explosion mechanisms remain poorly understood,particularly at varying dust concentrations.This study systematically investigates the effects of different aluminum powder mass percentages and dust concentrations(300 g/m^(3),600 g/m^(3),900 g/m^(3))on RDX dust explosion severity,flame propagation behavior,and gaseous products.The results indicate that the maximum explosion pressure peaks at 35%RDX,65%RDX,and 80%RDX at 300 g/m^(3),600 g/m^(3),and 900 g/m^(3),respectively.Concurrently,the time for the flame to propagate to the wall(t1)reaches minimum values of 34.8 ms,25.66 ms,and 23.93 ms.The maximum rate of pressure rise is observed for pure RDX at 900 g/m^(3).Aluminum powder enhances flame propagation velocity and combustion duration,as validated by the flame propagation system.Overall,the concentrations of carbon oxides(CO+CO_(2))decrease significantly with increasing aluminum mass percentage.At 20%RDX,the concentrations decreased by 51.64%,72.31%,and 79.55%compared to pure RDX at 300 g/m^(3),600 g/m^(3),and 900 g/m^(3),respectively.Notably,N_(2)O concentration only at 300 g/m^(3)showed such a trend.It rises first and then falls at 35%RDX at 600 g/m^(3)and 900 g/m^(3).These findings elucidate the synergistic explosion mechanisms and provide critical guidelines for safe production and handling.
基金supported by a grant from the Ministry of Research, Innovation and Digitization, UEFISCDI, Grant Nos. PN-IIIP2-2.1-PED-2021-1890, PN-IV-P6-6.3-SOL-2024-2-0254 and PNIV-P7-7.1-PTE-2024-0517, within PNCDI Ⅳ.
文摘This study represents an important step forward in the domain of additive manufacturing of energetic materials.It presents the successful formulation and fabrication by 3D printing of gun propellants using Fused Deposition Modeling(FDM)technology,highlighting the immense potential of this innovative approach.The use of FDM additive manufacturing technology to print gun propellants is a significant advancement due to its novel application in this field,which has not been previously reported.Through this study,the potential of FDM 3D-printing in the production of high-performance energetic composites is demonstrated,and also a new standard for manufacturability in this field can be established.The thermoplastic composites developed in this study are characterized by a notably high energetic solids content,comprising 70%hexogen(RDX)and 10%nitrocellulose(NC),which surpasses the conventional limit of 60%energetic solids typically achieved in stereolithography and light-curing 3D printing methods.The primary objective of the study was to optimize the formulation,enhance performance,and establish an equilibrium between printability and propellant efficacy.Among the three energetic for-mulations developed for 3D printing feedstock,only two were suitable for printing via the FDM tech-nique.Notably,the formulation consisting of 70%RDX,10%NC,and 20%polycaprolactone(PCL)emerged as the most advantageous option for gun propellants,owing to its exceptional processability,ease of printability,and high energetic performance.
基金supported by the Young Scientists Fund of National Natural Science Foundation of China(Grant Nos.12202202 and 12202494)the National Key Research and Development Program of China(Grant No.2021YFC3100700)。
文摘The internal and external flow fields during vented explosions of methane were characterized through numerical simulation,and the capability of numerical simulation thereof was validated by previous experimental data at three ignition positions.The venting mechanism was revealed by the simulated concentration distribution,temperature profile,and airflow velocity.The results show rear ignition results in the external methane mass distribution taking the form of"mushroom"and columnar flames in the external space,which can be expressed as a third-order polynomial relationship with distance;central ignition forms a relationship of the form y=AxB.Front ignition causes the temperature to show a tendency to repeated oscillations(rising,falling,and rising).Central ignition generates the maximum vented airflow velocity(V_(max)=320 m/s)upon vent opening.The results indicate that it is acceptable to apply numerical simulation of methane explosions in practice.
基金support provided by the National Natural Science Foundation of China(Grant No.12102405)the Presidential Foundation of CAEP(Grant No.YZJJZQ2023008).
文摘This study investigates the paradoxical detonation behavior of TKX-50,a nitrogen-rich energetic material,exhibiting higher detonation velocities but lower metal acceleration ability compared to HMX.Through experimental measurements and theoretical calculations,we propose a novel three-factor competition mechanism to explain this phenomenon.TKX-50-based PBX formulations achieved detonation velocities up to 9100 m/s,surpassing HMX-based counterparts.However,cylinder expansion tests revealed a 15%reduction in metal acceleration ability.Thermochemical measurements showed lower detonation heat for TKX-50(4900 J/g)versus HMX(5645 J/g).Our mechanism involves:(1)compositional effects prevailing at high pressures;(2)Energy release becoming essential as pressure drops;(3)Pressure-dependent product composition evolution functioning at low pressure.VLW code calculations unveiled a"crossover"in Hugoniot curves,lending support to this mechanism.This study furnishes a new framework for comprehending the performance of nitrogen-rich energetic materials,with significant implications for the design and optimization of future high-energy density materials.
文摘The desensitization of nitramine explosives while maintaining energetic performance is challenging.A highly efficient desensitizer is the key to solving the antinomy.This study focuses on using porous organic cages(POCs),specifically CC3 and RCC3,to desensitize RDX.By coating 0.1 wt%–5 wt%of POCs on RDX particles,a series of composite energetic materials were prepared.Characterization results show that POCs change the surface morphology of RDX,and there are interfacial interactions between them.The RDX@POCs composites exhibit enhanced stabilities in terms of heat,impact,friction,and electrostatic spark.For the RDX@RCC3-5%composite,the impact sensitivity(E_(IS)),friction sensitivity(E_(FS)),and electrostatic sensitivity(EES)were significantly reduced by 66.7%,68.8%,and 56.5%,respectively,while the detonation velocity decreased by merely 3.1%.These findings indicate that POCs,especially RCC3,are promising desensitizers for nitramine explosives,and their desensitization mechanisms likely involve barrier and buffering effects.The distinct desensitization behavior of RDX@RCC3 highlights the effectiveness of POCs in reducing the sensitivity of RDX without significantly compromising its energetic properties.
文摘With different structural forms of ventilation pipes have various attenuation effects on incident shock waves while meeting ventilation requirements.The attenuation mechanism and the propagation law of shock waves in ventilation pipes of different structures are investigated by experiments and numerical simulations.Furthermore,for the same structure,the effects of peak pressure and positive pressure time on the attenuation rate are discussed.It is found that the attenuation rate increases with the incident shock wave pressure,and the shock wave attenuation rate tends to reach its limiting value k for the same structure and reasonably short positive pressure time.Under the same conditions,the attenuation rate is calculated using the pressure of the shock wave as follows:diffusion chamber pipe,branch pipe and selfconsumption pipe;the attenuation rate per unit volume is calculated as follows:self-consumption pipe,branch pipe and diffusion chamber pipe.In addition,an easy method is provided to calculate the attenuation rate of the shock wave in single and multi-stage ventilation pipes.Corresponding parameters are provided for various structures,and the margin of error between the formulae and experimental results is within 10%,which is significant for engineering applications.
基金supported by the National Natural Science Foundation of China(Gant Nos.11372291 and 11902298)。
文摘Detonation performance is crucial for evaluating the power of high explosives(HEs),and the equation of state(EOS)that accurately describes the high-temperature,high-pressure,and high-temperature,medium-pressure states of detonation products is key to assessing the damage efficiency of these energetic materials.This article examines the limitations of the VLW EOS in representing the thermodynamic states of explosive detonation gas products under high-temperature and medium-to high-pressure conditions.A new gas EOS for detonation products,called VHL(Virial-Han-Long),is proposed.The accuracy of VHL in describing gas states under high-temperature and medium-to high-pressure conditions is verified,and its performance in evaluating explosive detonation and working capabilities is explored.The results demonstrate that VHL exhibits high precision in calculating detonation performance.Subsequently,the detonation performance of three new HEs(ICM-101,ONC,and TNAZ)was calculated and compared to traditional HEs(TATB,CL-20,and HMX).The results indicate that ONC has superior detonation performance compared to the other explosives,while ICM-101 shows a detonation velocity similar to CL-20 but with slightly lower detonation pressure.The detonation characteristics of TNAZ are comparable to those of the standard HE HMX.From the perspective of products,considering the comprehensive work performance(mechanical work and detonation heat),both ONC and ICM-101demonstrate relatively superior performance.
文摘The concept of TNT(Trinitrotoluene,C_7H_5N_3O_6)equivalence is often invoked to evaluate the performance and predict the explosion parameters of different types of explosives.However,due to its low prediction accuracy and limited application range,the use of TNT equivalence for predicting explosion parameters in a confined space is rare.Compared with explosions in free fields,the process of explosive energy release in a confined space is closely related to various factors such as oxygen balance,combustible components content,and surrounding oxygen content.Studies have shown that in a confined space,negative oxygen balance explosives react with surrounding oxygen during afterburning,resulting in additional energy release and enhanced blast effects.The mechanism of energy release during afterburning is highly complex,making it challenging to determine the TNT equivalence for blast effects in a confined space.Therefore,this remains an active area of research.In this study,internal blast experiments were conducted using TNT and three other explosives under both air and N_2(Nitrogen)conditions to obtain explosion parameters including blast wave overpressure,quasi-static pressure,and temperature.The influences of oxygen balance and external oxygen content on energy release are analyzed.The author proposes principles for determining TNT equivalence for internal explosions while verifying the accuracy of obtained blast parameters through calculations based on TNT equivalence.These findings can serve as references for predicting blast performance.
