Different Types Of Explosives Research Articles

Investigation on rock damage associated with ice-filling borehole blasting

Rock excavation and ore extraction in cold regions (e.g., alpine and high-altitude regions) are often conducted using the drill and blasting method. Ice may be presented in boreholes drilled in cold regions due to the potential freezing of water (e.g., water in rock fractures and pores) flowing into boreholes from the surrounding ground. The performance of rock blasting is inevitably affected by the presence of ice and no study has examined the effect of ice in boreholes on rock blasting performance. The present study investigates rock damage induced by the ice-filling borehole blasting. The damage modes and mechanisms of rock mass under the ice-filling borehole blasting are analyzed. The differences of rock damage induced by the sole ice-filling borehole blasting and the ice-water and ice-air mixed filling borehole blasting are identified. The effects of ice volumes in boreholes on blast-induced rock damage are examined. It is found that blast-induced rock damage is greatly reduced as water in boreholes turns into ice. In addition, the blasting with the ice volume greater than 6.7 % filled at the bottom of borehole can induce less rock damage compared to full-coupled charge blasting. To improve the performance of rock blasting with ice-filling boreholes, the effects of two methods, i.e., changing ignition locations and using different types of explosives on rock damage induced by the ice-filling borehole blasting are investigated. An empirical formula of rock damage volume incorporating ice volume, explosive properties, and rock properties is finally proposed as the reference for the design of ice-filling borehole blasting in cold regions.

Numerical Simulation Study of Cavity Formation in Soil under Blast Load

The main applications of civil explosives in soils are soil compaction, mass excavation, and in situ pile creation. The suitability of explosives for each of these applications strongly depends upon the explosive properties and the soil properties. For those reasons, a reliable estimation or process simulation regarding cost efficiency and explosive work ability in the soil with known soil parameters is relevant. This paper presents a numerical simulation study of different types of soil (different amounts of gravel, sand, silt, and clay) under a blast load modeled using Ansys 2020 R1 Autodyn 2D hydrocode, with different types of explosives. The calculated results from the Ansys 2020 R1 Autodyn 2D and the experimental results obtained from the in situ cavity formation caused by blasting are presented. The Jones–Wilkins–Lee (JWL) equation of state parameters was calculated using EXPLO5 V7.01.01 supported by experimental data, while the soil and explosive properties were measured in laboratory and in situ.

Characteristics and variation laws of electromagnetic radiation generated during explosion

AbstractThe characteristics and laws of explosive electromagnetic radiation must be clarified to investigate its interference with electronic equipment. Currently, studies pertaining to explosive electromagnetic radiation are performed via small equivalent explosive explosion tests, and conclusions regarding the regularity of electromagnetic radiation from warhead explosions are not confirmed. This study analyzes the power laws of explosion electromagnetic radiation via numerical simulations, literature comparisons, experimental testing, and other methods. The results show that the duration of the explosion electromagnetic radiation is proportional to the 1/3 power of the equivalent. The delay time is between 44 and 53 μs and is inversely proportional to the detonation velocity. The peak time is positively correlated with the 1/2 power of the equivalent. The electric field intensity of an explosive explosion is directly proportional to the 1/3 power of the equivalent, whereas the electric field intensity of a warhead explosion is positively correlated but not linearly related with the equivalent power. The spectral distribution of the electromagnetic radiation caused by different types of explosives differ significantly. The electromagnetic radiation measurement results for explosive explosions can be predicted via numerical simulation. However, the simulation results do not match the measurement data of warhead explosions, thus highlighting the necessity of warhead explosion electromagnetic measurements.

Development of an analytical exponential-6 equation of state through Monte Carlo simulations.

The exponential-6 (exp-6) potential is commonly used to model fluids at high densities. In this paper, I propose a new equation of state (EOS) in the form of an analytical expression for the excess Helmholtz free energy of an exp-6 fluid. The EOS is based on extensive Monte Carlo simulations and therefore combines the excellent accuracy of the simulations with the numerical efficiency of a polynomial expression. The mean relative error in compressibility factor and internal energy is 0.14% and 0.25% respectively, which is a significant improvement over statistical mechanical theories. The EOS was implemented into a thermochemical code in order to optimize gas parameters and evaluate its performance on pure gas data, shock compression and detonation properties. Predicted gas densities, heat capacities and speed of sound for pure gases were generally within experimental uncertainties at pressures up to 1GPa and temperatures above 300K. For polar molecules, a simple free energy correction was introduced which greatly improved accuracy at low temperature. Calculated shock Hugoniots showed excellent agreement with experimental values up to 150GPa and 10 000K, and the detonation performance was accurately predicted for a number of different types of explosives.

Research on Comprehensive Performance Optimization Method of Explosives and Propellants Oriented to the Whole Process

Explosives and propellants are common basic energy for weapons and equipment to achieve delivery, damage, and control, and are an important manifestation of national defense power. However, due to the wide variety of products and complex performance, the traditional serial design optimization mode can no longer meet the requirements of product diversification and rapid development. In this paper, the design process of explosives is deeply studied, and a method for optimizing the comprehensive performance of explosives and propellants oriented to the whole process is proposed. The method uses a comprehensive performance optimization engine to numerically model different design links in a unified parameter space, connects different links horizontally, and adopts a multi-objective optimization algorithm to comprehensively consider the optimization objectives of different links, realizing the automatic execution of the optimization process according to the design process. In order to verify the effectiveness of the method, this paper optimizes the formula of explosives and propellants based on two different types of explosives, gun propellant and rocket propellant. Experimental results show that this method improves the design efficiency and improves product quality under the premise of ensuring safety and manufacturability.

Explosion Differentiation Using Light Emissions—Nuclear Reactor, Steam, Water Hammer, Hydrogen, Piper Alpha, and Hydro-Volcanic Explosions

Abstract Light emissions during chemical reactions provide insights into various scenarios to better understand explosions and water hammers. For example, hydrogen burning and explosions emit blue light, organic carbon combustion and explosions emit combinations of blue and yellow light, water phase changes emit infrared and less visible white light, and white light explosions ignite when multiple chemical reactions are involved. Since experimental tests to observe infrared light during water hammers have not yet been performed, test data from water boiling tests and volcanoes are compared to larger water hammer and steam explosion incidents. Considering these facts and examining a series of photos and videos from the literature and Internet, determinations are proven with respect to water hammers, steam explosions, Piper Alpha water hammer explosions, and chemical explosions. Such evidence proves that steam explosions are important for water hammer accidents, but chemical explosions explain other explosions that have long been considered to be steam explosions. These other explosions include nuclear power plant explosions, hydro-volcanic explosions, and hydrogen explosions, where some of these explosions are, in fact, related to water hammers. This article is primarily a photographic essay to explain the differences between different types of explosions and water hammers, although combustion and explosion principles are expanded and explained to support this essay.

Formation of Shaped Charge Projectile in Air and Water.

With the improvement of the antiknock performance of warships, shaped charge warheads have been focused on and widely used to design underwater weapons. In order to cause efficient damage to warships, it is of great significance to study the formation of shaped charge projectiles in air and water. This paper uses Euler governing equations to establish numerical models of shaped charges subjected to air and underwater explosions. The formation and the movement of Explosively Formed Projectiles (EFPs) in different media for three cases: air explosion and underwater explosions with and without air cavities are discussed. First, the velocity distributions of EFPs in the formation process are discussed. Then, the empirical coefficient of the maximum head velocity of EFPs in air is obtained by simulations of air explosions of shaped charges with different types of explosives. The obtained results agree well with the practical solution, which validates the numerical model. Further, this empirical coefficient in water is deduced. After that, the evolutions of the head velocity of EFPs in different media for the above three cases are further compared and analyzed. The fitting formulas of velocity attenuation of EFPs, which form and move in different media, are gained. The obtained results can provide a theoretical basis and numerical support for the design of underwater weapons.

Fractal Analysis for Wave Propagation in Combustion–Explosion Fracturing Shale Reservoir

The in-situ combustion–explosion fracturing technology in shale reservoirs can promote continuous fracture expansion with a radial detonation wave first converging into a shock wave and then decaying into an elastic wave. The transformation scale of the shale reservoir is determined by the range of wave propagation during combustion–explosion. As wave propagation paths are usually tortuous and fractal, the previous integer wave models are not competent to describe the wave propagation and estimate the impact range of the combustion–explosion fracturing process. This study develops two fractional wave propagation models and seeks analytical solutions. Firstly, a novel fractional wave model of rotation angle is proposed to describe the process of detonation waves converting into shock waves in a bifurcated structure. The radial displacement gradient of the detonation wave is represented by the internal expansion and rotation deformation of the shale. Secondly, another fractional wave propagation model of radial displacement is proposed to show the process of a shock wave decaying into an elastic wave. Thirdly, the proposed models are analytically solved through the fractional variable separation method and variational iteration method, respectively. Analytical solutions for rotation angle and radial displacement with fractal time and space are obtained. Finally, the impacts of the branching parameter of the detonation wave converge bifurcation system, aggregation order of detonation compression wave, and different types of explosives on the rotation angle of the shock wave are investigated. The propagation mechanism of the primary wave (P-wave) with time and space is analyzed. The analytical solutions can well describe the wave propagation process in fractured shales. The proposed fractional wave propagation models can promote the research of wave propagation in the combustion–explosion fracturing process of shale reservoirs.

Numerical simulation of the effect of water-decoupling charge blasting on reservoir permeability enhancement

In the development of deep resources, blasting fracturing technology is one of the most effective means to improve the permeability of otherwise low-permeability reservoirs, while the pressure rise time of shock wave and the charge structure are the key factors affecting the blasting effect. Thus, this paper first deduces a formula for the pressure rise time, based on which, the blast-induced damage evolution is numerically simulated, and the numerical result is consistent with the existing studies, which verifies the feasibility of the formula. In addition, the influence of decoupling coefficients (K) of different types of explosives (i.e. TNT, emulsion, and ANFO explosives) on the damage range of reservoir blasting is studied. It is found that under the blasting of different types of explosives, the damage evolution law of the reservoir is different, and appropriate explosives should be selected in combination with rock stratum parameters in actual construction. Finally, the increase in permeability and the drainage effect of the reservoir after blasting are quantified by numerical simulations. It is demonstrated the average permeability increment of the reservoir under the action of TNT explosive is the largest, which is 3.08 (K = 4), while that under the action of emulsion explosive and ANFO explosive are 1.49 (K = 2) and 1.17 (K = 3) respectively; and the changes in reservoir permeability and drainage volume are coherent with the range of damage; the greater the range of damage, the greater the reservoir permeability and the greater the drainage efficiency.

Injuries From Explosions: More Differences Than Similarities Between Various Types.

To compare injury patterns of different types of explosions. A retrospective study of 4508 patients hospitalized due to explosions recorded in the Israel National Trauma Registry between January 1997 and December 2018. The events were divided into 4 groups: terror-related, war-related, civilian intentional explosions, and civilian unintentional explosions. The groups were compared in terms of injuries sustained, utilization of hospital resources, and clinical outcomes. Civilian intentional and terror-related explosions were found to be similar in most aspects except for factors directly influencing mortality and a larger volume of severely injured body regions among terror-victims. Comparisons between other groups produced some parallels, albeit less consistent. Civilian intentional explosions and civilian unintentional explosions were different from each other in most aspects. The latter group also differed from others by its high volume of life-threatening burns and a higher proportion of children casualties. While consistent similarities between explosion casualties exist, especially between victims of intentional civilian and terror-related explosions, the general rule is that clinical experience with a type of explosion cannot be directly transferred to other types.

High Quantum Yield Nitrogen-Doped Carbon Quantum Dot-Based Fluorescent Probes for Selective Sensing of 2,4,6-Trinitrotoluene

Fluorescent carbon quantum dots hold great promise for the determination of nitro-explosive 2,4,6-trinitrotoluene (TNT), a potential environmental pollutant. Here, a nitrogen-doped carbon quantum dot (N-CQD)-based fluorometric probe with high quantum yield (73.10%) was developed for the selective determination of TNT. N-CQDs were synthesized by the reflux method using citric acid (CA) as a carbon precursor and ethylenediamine (EDA) with diaminocyclohexane (DACH) as nitrogen precursors. N-CQDs, with excitation and emission wavelengths of 360 and 460 nm, respectively, were highly selective toward TNT among different types of explosives [i.e., tetryl, 2,4,6-trinitrophenol (TNP), 2,4-dinitrotoluene (DNT), 4-amino-2,6-dinitrotoluene (ADNT), HMX, 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), and pentaerythritol tetranitrate (PETN)]. As a result of the dominant FRET mechanism secondarily assisted by ground-state donor–acceptor complexation, the fluorescence of N-CQDs showed excellent quenching in the presence of TNT. The structure of N-CQDs was elucidated using X-ray photoelectron spectroscopy, X-ray diffraction, IR, Raman, high-resolution transmission electron microscopy, and dynamic light scattering techniques, and their interaction mechanism with TNT was resolved using the Gaussian (i.e., highest occupied molecular orbital–lowest unoccupied molecular orbital energy levels) program. The limit of detection and limit of quantification in aqueous media were 30.0 and 90.0 nM, respectively, while the Benesi–Hildebrand binding constant of N-CQDs was 2.22 × 103. In the presence of common soil ions, explosive mixtures, and camouflage materials, the N-CQDs could determine TNT with recoveries between 94.9 and 104.9%. In addition, sandy soil specimens were artificially contaminated with TNT as real samples, and the TNT extracted from these samples was determined by both N-CQDs and the reference liquid chromatography with tandem mass spectrometry method to validate the proposed fluorometric method. To design field detection techniques, two different support materials based on the thin layer chromatography-paper and hydrogel (N-CQD-gel) were developed, and TNT was determined visually at a μM level with both materials. The developed support materials make N-CQDs potentially useful in environmental sensor applications with their selective and sensitive sensing ability.

Experimental and Empirical Study for Prediction of Blast Loads

This paper presents the issue of determining the blast load on an engineering structure. In cases of industrial accidents or terrorist attacks, in many cases it is necessary to determine the necessary explosion parameters to determine the response of the structure, preferably in a simple and time-saving manner. In such a way, the empirical relationships can be used to estimate the selected parameters of the explosion load. Many empirical relationships have been derived in the past, but not all are suitable for different types of explosions. This article compares and validates experimentally determined selected explosion parameters for the chosen explosive with empirical relationships. For comparison, three already verified and frequently used calculation procedures (Kingery, Kinney, Henrych) and one newly derived procedure (PECH) were used. As part of the experimental measurements, blast wave explosion parameters for small charges were determined for near-field explosions. The general-purpose plastic explosive Semtex 10-SE was used for the experiments. The results of the comparative study presented in this article demonstrate the importance of taking these procedures into account for a reliable determination of the effects of blast actions on buildings.

A Study on Parameters Influencing Blast-Induced Frequency Content and Dominant Frequency Attenuation

Adverse effects of the blasting vibration on surrounding structures intensify importance of investigation on the blast frequency content while it has not been fully considered in blasting design. In this study, blast-induced frequency content and dominant frequency attenuation are investigated. The results of this study and its comparison with the previous studies demonstrate that investigation of different parameters influencing blast-induced frequency content including peak blast load pressure, rise time, and falling time by the experimental pressure-time history with its Fast Fourier Transform (FFT) analysis leads to the similar results of study by the velocity-time recorded data of an infield blasting. The outcomes of this study on dominant frequency attenuation for different types of explosives but in the same material show approximately the same dominant vibration frequency in far-field for different explosives, whereas a rapid drop of dominant frequency to half of the initial value in near distance to the blasthole can be observed. Investigation on dominant frequency attenuation versus distance for the materials with different natural ground frequencies demonstrates that the geomaterial tends to pass the vibration frequency closer to its natural frequency. If the earth has a lower natural frequency, it will pass the waves with lower dominant frequencies, but it will attenuate the waves with higher dominant frequency.

Vapor cloud explosions in various types of confined environments: CFD analysis and model validation

In the current work, three different types of vapor cloud explosion experiments are simulated. The purpose of the simulations is twofold: firstly, to evaluate a recently developed CFD model and secondly to analyze the involved phenomena with the help of the simulation results. The proposed model, which has been implemented in the ADREA-HF CFD code, utilizes the RANS method using the Kato and Launder modification of k-e model. Combustion is modelled by taking into account the main mechanisms that contribute to the phenomenon such as chemistry, turbulence generated from the obstacles in front of the flame front, flame instabilities and turbulence generated by the flame-front itself. The CFD model is evaluated against different types of explosions in different geometries and with various fuels. Uniform premixed fuel-air mixture is considered in all cases. A large scale vented deflagration experiment in a 10 m length enclosure is firstly simulated using methane as fuel. The external explosion effect is apparent in this case. Then, a hydrogen deflagration experiment in a 78.5 m tunnel is simulated. Four mock-up cars are placed in the premixed region. Finally, propane and methane explosions inside a 1.5 m tube with obstacles and intense turbulence are simulated. Two different obstacle configurations are studied. The model predicts the overpressure values satisfactorily in all the examined cases. The factors that contribute to the pressure rise in each stage of each experiment are discussed based on the simulation results.

Dependency of the Blast Wave Pressure on the Amount of Used Booster

Most of the damage caused by an explosion is caused by a pressure effect. The magnitude of the pressure generated by the explosion is influenced by the external characteristics of the environment (surrounding objects, their arrangement, geometry, etc.) and internal characteristics (type of explosive, type of charge, booster and others). An effective combination of internal factors creates a symmetry that results in the highest possible value of pressure generated by the charge explosion. The paper focuses on the influence of the booster reaction on this symmetry. The scope of the paper is to understand the dependency of the blast wave pressure on the amount of used blaster to increase the efficacy of explosions on the environment and structures to increase the protection of affected structures. The open-air field tests were conducted using different types of explosives: trinitrotoluene and three different types of industrially made ANFO explosives (pure ammonium nitrate and fuel oil, ammonium nitrate and fuel oil plus aluminum powder, ammonium nitrate and fuel oil mixed with trinitrotoluene). The obtained data were compared with the analytical approach for setting the generated maximal pressure on the front of the blast wave.

FORMATION OF PARAMETERS OF FOAMED EXPLOSIVE MIXTURES FOR SEALING SOILS

Significant growth rates of construction require large areas prepared in advance. Given the complexity and large scale of construction on subsidence soils, an important issue remains their compaction. On the article, on the parameters of the explosion momentum of TNT-free explosive compositions based on ammonium nitrate (AN) and after ultrasonic treatment of ammonium nitrate were analytically investigated, and their comparison with ammonite №6 and igdanite was also compared. The principles of explosive pulse control by regulating the content and density of explosives due to ultrasonic radiation and foaming of low-density explosive mixtures have been developed and substantiated. Set the minimum value of the peak pressure at the interface "detonation product - environment" from time for foamed explosives after treatment with ultrasonic radiation. The object of research: Reclamation works and construction. Management of compaction of subsidence and flooded soils by directed action of explosive systems. Investigated problem: Taking into account that the method of compaction of subsiding loess soils with the energy of explosion is used in built-up areas, of particular importance is the control of the explosive pulse through the regulation of the content and density of explosives by ultrasonic radiation and foaming of low-density explosive mixtures this is done to ensure the required degree of compaction of the subsidence of the soil mass and to reduce the harmful seismic impact on the surrounding structures. The main scientific results: The dependence of the duration of the explosive pulse growth on the charge radius for different types of low-density explosives has been established, which indicates that the longest growth time of the explosive pulse is observed for charges based on foamed explosives, both conventional and ultrasonic treated. The dependences of the degree of soil compaction during the explosion of overhead charges of different types of explosives in the polymer housing on the specific costs of explosives are obtained. The research results allow to develop technological methods of controlling the parameters of the explosive pulse by using explosive density, which provides the opportunity to increase the efficiency of explosive energy to maintain the required degree of compaction of subsidence loess soils to a certain depth while seismic protection. The area of practical use of the research results: the use of this type of compaction of unstable soil is possible in the construction industry, in the mining industry and in the military. Innovative technological product: the methods of compaction of unstable soil with the energy of the explosion work when changing the parameters of the pulse, which will minimize the loss of energy in the blasting zone and increase the range of a single charge. Scope of the innovative technological product: the application of this method is possible: for compaction of unstable soil before construction, for soil compaction of runways at field airfields, for demining.

Probabilistic models for blast parameters and fragility estimates of steel columns subject to blast loads

This paper proposes a probabilistic framework to predict the failure probabilities of steel columns subject to blast loads. The framework considers the uncertainties in the blast phenomenon, the demands imposed on the column, and the capacities of the column for the limit states of flexure, and global buckling. As part of the work, we propose four probabilistic blast load models. For different types of explosives and atmospheric conditions, two models predict the incident and reflected peak pressure generated by the explosion and two models predict the incident and reflected positive time duration of the blast wave. The models are probabilistic to capture the associated uncertainties, including variations in the atmospheric conditions, the inherent variability in the blast load data even for identical experimental conditions, and model error. The blast load models are used to predict the structural demands (maximum internal moment and deflection) imposed by the blast on a column. The demand models are combined with strain-rate dependent capacity models for flexure and global buckling to estimate the conditional probability of failure (or fragility) of a steel column for given scaled distance. As an example, fragility estimates for different columns representative of typical columns in steel frames are developed. The results highlight the importance of the explosive weight and column axial load on the failure probabilities.

Quantification and analysis of air blast load propagation characteristics on structures

The detonation of an explosive charge extremely near or above the ground could be devastating causing deformation to the structural frame of the building, cracking of walls, exploding huge areas of windows and shattering all kinds of life saving systems. Depending upon the type and size of explosive used, the possible structural collapse happens when the blast waves produced during explosion, impacting the structure over time. This paper presents to study the characteristics of blast waves and understanding the relationships between various parameters considered in blast loading such as incident overpressure, reflected overpressure, phase duration and scaled distance. Analysis and quantification of uncertainties of the TNT equivalency of different explosives with respect to pressure and impulse observed. Focus was given to formulate an empirical equation from the extracted experimental data considering the influential parameters affecting the blast resistant design that governs the modeling of blast loads. This equation could help in predicting the safe distances beyond which the blasting of different types of explosives would cause minimum impact on the structure. Thus for designing a structure to be resisting blast weight, the foremost important task is to have a realistic overview about the prediction of pressures impacting on a structure and this paper gives essential outline of the detonating effects due to various types of explosives on structures.

Electric charging of eruptive clouds from Shiveluch Volcano caused by different types of explosions

The number of explosive eruptions at Shiveluch Volcano has significantly increased over the past years, which requires close volcanic monitoring using all available techniques. In order to implement a new monitoring technique into integrated methods of volcano monitoring, the authors analyze response to the intensity of the vertical component in the atmospheric electrical field (EZ AEF) during the movement of ash clouds. Two eruptions of different intensity that occurred December 16, 2016 and June 14, 2017 at Shiveluch were selected for study. We used a combination of satellite, seismic, and infrasound data to select signals in the EZ AEF field. Signals with negative polarity that accompanied ashfalls in the EZ AEF dynamics were registered for both eruptions within the closest area (< 50 km). In the former case, the ash cloud was “dry” and thus it caused aerial-electrical structure of the negatively charged cloud. In the latter case, a strong explosion sent into the atmosphere the large volume of ash and volcanic gases (98% in form of vapour) that resulted in the formation of a dipolar aerial-electrical structure caused by eolian differentiation within the closest area. At the distance of more than 100 km we registered a positive-going signal that is attributive to the aerial-electrical structure of the positively charged type of the cloud.

Electric charging of eruptive clouds from Shiveluch Volcano caused by different types of explosions

The number of explosive eruptions at Shiveluch Volcano has significantly increased over the past years, which requires close volcanic monitoring using all available techniques. In order to implement a new monitoring technique into integrated methods of volcano monitoring, the authors analyze response to the intensity of the vertical component in the atmospheric electrical field (EZ AEF) during the movement of ash clouds. Two eruptions of different intensity that occurred December 16, 2016 and June 14, 2017 at Shiveluch were selected for study. We used a combination of satellite, seismic, and infrasound data to select signals in the EZ AEF field. Signals with negative polarity that accompanied ashfalls in the EZ AEF dynamics were registered for both eruptions within the closest area (< 50 km). In the former case, the ash cloud was “dry” and thus it caused aerial-electrical structure of the negatively charged cloud. In the latter case, a strong explosion sent into the atmosphere the large volume of ash and volcanic gases (98% in form of vapour) that resulted in the formation of a dipolar aerial-electrical structure caused by eolian differentiation within the closest area. At the distance of more than 100 km we registered a positive-going signal that is attributive to the aerial-electrical structure of the positively charged type of the cloud.