Blast Simulation Research Articles

A closed-body preclinical model to investigate blast-induced spinal cord injury.

Blast-induced spinal cord injuries (bSCI) are common and account for 75% of all combat-related spinal trauma. It remains unclear how the rapid change in pressure contributes to pathological outcomes resulting from these complex injuries. Further research is necessary to aid in specialized treatments for those affected. The purpose of this study was to develop a preclinical injury model to investigate the behavior and pathophysiology of blast exposure to the spine, which will bring further insight into outcomes and treatment decisions for complex spinal cord injuries (SCI). An Advanced Blast Simulator was used to study how blast exposure affects the spinal cord in a non-invasive manner. A custom fixture was designed to support the animal in a position that protects the vital organs while exposing the thoracolumbar region of the spine to the blast wave. The Tarlov Scale and Open Field Test (OFT) were used to detect changes in locomotion or anxiety, respectively, 72 h following bSCI. Spinal cords were then harvested and histological staining was performed to investigate markers of traumatic axonal injury (β-APP, NF-L) and neuroinflammation (GFAP, Iba1, S100β). Analysis of the blast dynamics demonstrated that this closed-body model for bSCI was found to be highly repeatable, administering consistent pressure pulses following a Friedlander waveform. There were no significant changes in acute behavior; however, expression of β-APP, Iba1, and GFAP significantly increased in the spinal cord following blast exposure (p < 0.05). Additional measures of cell count and area of positive signal provided evidence of increased inflammation and gliosis in the spinal cord at 72 h after blast injury. These findings indicated that pathophysiological responses from the blast alone are detectable, likely contributing to the combined effects. This novel injury model also demonstrated applications as a closed-body SCI model for neuroinflammation enhancing relevance of the preclinical model. Further investigation is necessary to assess the longitudinal pathological outcomes, combined effects from complex injuries, and minimally invasive treatment approaches.

Method to map human and infrastructure vulnerability using CNN land cover: Case study of floating tank explosion at petrochemical plants of LaemChabang, Thailand

Industrial storage tanks, used to store flammable materials in the petrochemical industry, can induce potential fire and explosion under specific conditions. Therefore, it is necessary to map the population and environment vulnerability, and, to develop procedures for emergency responses in order to reduce potential casualties. In order to achieve this, Convolutional Neural Networks (CNN) are used in this study using 6 classes: floating tank, forest, house, road, wasteland and water. Datasets are built for a total of approximately 1.4 million tiles with a resolution of 0.33m/pixel and their size are optimized in function of the class. The 6 associated CNN models are built and optimized to classify each class. The validation of the models shows that, with the exception of road and wasteland where the precision is only 73% and 89% respectively, the other 4 classes have a value higher than 95%. Post-processing is performed on each prediction before aggregating these results to obtain the land cover. For the floating tank class, a 5 step post-processing is used based on a Density-Based Spatial Clustering of Applications with Noise algorithm (DBCAN) after which blast simulation is applied and effects on people, buildings and trees are obtained through 4 steps. Finally, the petrochemical site of LaemChabang in Thailand is used as study case. Except for the road class that is difficult to detect, land cover is well performed. Human casualties and surface of damaged buildings are finally estimated demonstrating the usefulness of the tool to be used for the emergency planning of industrial disasters.

Dynamic response and failure analysis for urban bridges under far-field blast loads

Compared to near/mid-field explosions, the far-field blast generates blast waves with long duration and propagation distance, which will cause distinctly different damage effects. The dynamic response and failure mechanism of urban bridges under far-field blast loads are numerically investigated in this work. To address the excessive model scale caused by the direct simulation and remapping methods, approximate far-field blast waves are input into the air domain through the Autodyn subroutine in the present far-field blast simulations. The reliability of the loading method and the fluid-structure interaction simulation scheme adopted here is then demonstrated by published experimental data. Based on an urban bridge prototype, the refined numerical model of the bridge is established. Eventually, the failure process and damage modes of the bridge under far-field explosions are analyzed, while the effects of impact angles and load parameters are explored. The results imply that (i) the response of the bridge under far-field explosions is global, while the typical features in the response process are the pier tilt and superstructure uplift; (ii) the damage modes of the bridge include crush and twist of piers, damage to shear keys, cracking of bent caps, and movement of the superstructure; (iii) the decrease of impact angle exacerbates the pier displacement and reduces the superstructure uplift; (iv) for peak overpressure, decay parameter and positive phase duration, the bridge structural response is most sensitive to peak overpressure.

Analysis of flow field in a blast simulator combined-driven by explosive charge and compressed gas

The flow field characteristics of blast simulators with the explosive-driven method and compression-driven method have been extensively investigated; however, limited effort has been made to the flow field in blast simulators combined-driven by explosive charge and compressed gas. In this paper, the finite volume method governed by the Navier–Stokes equation based on an explosive detonation and k-omega SST turbulence equation was used to analyze the flow field characteristics of blast simulators with three kinds of drive methods, namely, explosive-driven method, compression-driven method, and combined-driven method. The results show that the numerical method could simulate the flow field characteristics of the blast simulators with the explosive-driven method and compression-driven method accurately by comparing to the experimental data. Also, the influence of air turbulence on the explosion flow field cannot be neglected in the case of long running time. It is obtained that the combined-driven method could increase the pressure peak value of shock waves and extends positive pressure duration effectively, owing to the interaction of the shock waves generated from the explosive detonation and the rarefaction wave formed by rupturing the diaphragm. The first overpressure peak value, the second overpressure peak value, and the positive pressure duration obtained by the combined-driven method of 5 kg TNT and 0.3 MPa compressed gas were 1.669 times, 2.172 times, and 2.308 times more than those obtained by the explosive-driven method of 5 kg TNT, respectively. The maximum overpressure and positive pressure duration obtained by the combined-driven method of 5 kg TNT and 0.3 MPa compressed gas were 2.56 times and 1.162 times more than those obtained by the compression-driven method of 0.3 MPa compressed gas, respectively. Moreover, various shock wave environments could be simulated by controlling the charge mass of explosive charge and the initial pressure of compressed gas.

Combined experimental and theoretical study on the blast response of arching masonry walls

This paper studies the nonlinear dynamic response of arching masonry walls to blast load. The methodology combines laboratory blast testing and nonlinear dynamic modeling of arching one-way masonry walls and their response to blast load. The paper aims at enhancing the understanding of the dynamic and nonlinear physical response of the structural system. The experimental phase focuses on a one-way arching masonry wall tested in a blast simulator. The test is designed to explore global and local measures of the response of such walls. New experimental data that contributes to the understanding of the blast response and for validating theoretical and numerical models is presented. The theoretical phase develops a nonlinear, dynamic, continuous beam-type model that considers the deformability of the mortar joints and the masonry units. The model combines inertial effects with geometrical and material nonlinearities and uses the finite element method for the numerical solution. The model is examined and evaluated against the experimental benchmark, and then it is used to explore the impact of the boundary conditions and the blast intensity on the dynamic response. The combined investigation highlights, explores, and quantifies the unique aspects of the complex dynamic response of such walls to blast loading.

Spatiotemporally resolved 5-MHz visualization and particle image velocimetry in early time multiphase blasts

Explosive blasts, used in a variety of engineering applications, have coupled multiphase dynamics, and require high-fidelity spatiotemporally resolved measurements to understand and accurately predict key design parameters. This study evaluates burst-mode laser-based particle-field visualization and particle image velocimetry (PIV) for planar measurements up to 5 MHz. This enhancement of time-resolved PIV represents an order-of-magnitude increase over the prior state of the art enabling measured velocities in the km/s regime. The technique is applied to a multiphase blast’s early (<10 µs) development to quantify the cross-sectional flow structure, velocity, acceleration, and pressure within the rapidly expanding particle field. The morphological evolution of the solid explosive products is characterized by a scale-independent shape parameter and the fractal dimension. This analysis highlights two flow development regimes (separated by 2 µs) in the expansion process. The high measurement resolution enables the characterization of significant differences in velocity and acceleration between the primary and secondary expansion directions. These orthogonal directions are located where the shock is attached and detached respectively from the solid products: each is driven by different forces in the flow. These measurements yield information about complex transport processes and may be useful for subsequent validation of high-fidelity multiphase blast simulations.

A simplified approach to modelling blasts in computational fluid dynamics (CFD)

This paper presents a time-efficient numerical approach to modelling high explosive (HE) blastwave propagation using Computational Fluid Dynamics (CFD). One of the main issues of using conventional CFD modelling in high explosive simulations is the ability to accurately define the initial blastwave properties that arise from the ignition and consequent explosion. Specialised codes often employ Jones-Wilkins-Lee (JWL) or similar equation of state (EOS) to simulate blasts. However, most available CFD codes are limited in terms of EOS modelling. They are restrictive to the Ideal Gas Law (IGL) for compressible flows, which is generally unsuitable for blast simulations. To this end, this paper presents a numerical approach to simulate blastwave propagation for any generic CFD code using the IGL EOS. A new method known as the Input Cavity Method (ICM) is defined where input conditions of the high explosives are given in the form of pressure, velocity and temperature time-history curves. These time history curves are input at a certain distance from the centre of the charge. It is shown that the ICM numerical method can accurately predict over-pressure and impulse time history at measured locations for the incident, reflective and complex multiple reflection scenarios with high numerical accuracy compared to experimental measurements. The ICM is compared to the Pressure Bubble Method (PBM), a common approach to replicating initial conditions for a high explosive in Finite Volume modelling. It is shown that the ICM outperforms the PBM on multiple fronts, such as peak values and overall overpressure curve shape. Finally, the paper also presents the importance of choosing an appropriate solver between the Pressure Based Solver (PBS) and Density-Based Solver (DBS) and provides the advantages and disadvantages of either choice. In general, it is shown that the PBS can resolve and capture the interactions of blastwaves to a higher degree of resolution than the DBS. This is achieved at a much higher computational cost, showing that the DBS is much preferred for quick turnarounds.

Numerical simulation of rock mass blasting vibration using particle flow code and particle expansion loading algorithm

In the numerical analysis of rock mass blasting using the particle expansion loading algorithm in the PFC method, the size of the blasting funnel is usually consistent with the experiment, but the blasting seismic wave produced is quite different from the reality. By reasonably determining the micro-parameters that affect the simulation effect of blasting vibration, the particle expansion loading algorithm can better simulate the actual situation of the blasting effect of the rock mass. The studied rock's density, uniaxial compressive strength, and elastic modulus are 2500 kg/m3, 80.1 MPa, and 65 GPa, respectively. Firstly, based on the theory of the PFC method and the law of energy conservation, the attenuation process of the seismic waves was controlled by the critical damping ratio and contact stiffness of the model. Then, the rock blasting numerical simulation is carried out using the particle expansion loading algorithm. The critical damping ratio mainly affects particle vibration's kinetic energy attenuation rate. At the same time, the contact stiffness can control both the peak velocity and the duration of blasting vibration. Finally, the field blasting experiment verifies the rationality of the quantitative relationship between the critical damping ratio and contact stiffness and the specific parameters of blasting seismic waves in the simulation of rock blasting vibration. It is verified that the particle expansion loading algorithm in the PFC method can not only simulate the blasting funnel forming well but also simulate the blasting vibration effect in the outlying area, which provides a more reliable numerical simulation method for the simulation of rock blasting.

Development of a novel bioengineered 3D brain-like tissue for studying primary blast-induced traumatic brain injury.

Primary blast injury is caused by the direct impact of an overpressurization wave on the body. Due to limitations of current models, we have developed a novel approach to study primary blast-induced traumatic brain injury. Specifically, we employ a bioengineered 3D brain-like human tissue culture system composed of collagen-infused silk protein donut-like hydrogels embedded with human IPSC-derived neurons, human astrocytes, and a human microglial cell line. We have utilized this system within an advanced blast simulator (ABS) to expose the 3D brain cultures to a blast wave that can be precisely controlled. These 3D cultures are enclosed in a 3D-printed surrogate skull-like material containing media which are then placed in a holder apparatus inside the ABS. This allows for exposure to the blast wave alone without any secondary injury occurring. We show that blast induces an increase in lactate dehydrogenase activity and glutamate release from the cultures, indicating cellular injury. Additionally, we observe a significant increase in axonal varicosities after blast. These varicosities can be stained with antibodies recognizing amyloid precursor protein. The presence of amyloid precursor protein deposits may indicate a blast-induced axonal transport deficit. After blast injury, we find a transient release of the known TBI biomarkers, UCHL1 and NF-H at 6 h and a delayed increase in S100B at 24 and 48 h. This in vitro model will enable us to gain a better understanding of clinically relevant pathological changes that occur following primary blast and can also be utilized for discovery and characterization of biomarkers.

Blast Exposure Dysregulates Nighttime Melatonin Synthesis and Signaling in the Pineal Gland: A Potential Mechanism of Blast-Induced Sleep Disruptions.

Blast-induced traumatic brain injury (bTBI) frequently results in sleep-wake disturbances. However, limited studies have investigated the molecular signaling mechanisms underlying these sleep disturbances, and potentially efficacious therapies are lacking. We investigated the levels of melatonin and genes involved in melatonin synthesis pathway in the pineal glands of Sprague Dawley rats exposed to single and tightly coupled repeated blasts during the night and daytime. Rats were exposed to single and tightly coupled repeated blasts using an advanced blast simulator. The plasma, cerebrospinal fluid (CSF), and pineal gland were collected at 6 h, 24 h, or 1 month postblast at two different time points: one during the day (1000 h) and one at night (2200 h). Differential expressions of genes involved in pineal melatonin synthesis were quantified using quantitative real-time polymerase chain reaction (qRT-PCR). Plasma and CSF melatonin levels were assessed using a commercial melatonin ELISA kit. The plasma and CSF melatonin levels showed statistically significant decreases at 6 h and 24 h in the blast-exposed rats euthanized in the night (in dim light), with no significant alterations noted in rats euthanized in the morning (daylight) at all three-time points. Blast-exposed rats showed statistically significant decreases in Tph1, Aanat, Asmt, and Mtnr1b mRNA levels, along with increased Tph2 mRNA, in the pineal gland samples collected at night at 6 h and 24 h. No significant changes in the mRNA levels of these genes were noted at 1 month. These findings imply that the melatonin circadian rhythm is disrupted following blast exposure, which may be a factor in the sleep disturbances that blast victims frequently experience.

Silencing a free field blast simulator to meet residential standards

The Naval Medical Research Center in Silver Spring, Maryland, plans to install a new free field blast simulator in an existing building on campus. The new blast simulator will be an addition to two current blast simulators and is capable of generating higher dynamic pressure levels, up to 35 psi, than the existing simulators by igniting a mixture of oxygen and acetylene to create the simulated blast. In order to accurately simulate the blast, the outlet of the simulator must be exhausted to the outdoors which will produce noise levels in excess of 140 dBA at five feet. The campus lies within 1800 feet of the nearest residential neighborhood and 950 feet of the nearest commercial neighborhood. The nearest outdoor occupied area on campus, a parking lot, is only 90 feet away. Sound pressure levels produced by the simulator as well as the exhaust requirements were evaluated in order to design a mitigation scheme to reduce noise to meet acceptable residential levels in the parking lot area. Phoenix Noise and Vibration worked with Vibro Acoustics to develop a silencer design to meet these criteria which will be reviewed in the presentation.

Numerical simulation of charge blasting without coupling to air media

Blasting technology is one of the means commonly used in the excavation process of stone tunnels, in the blasting technology, it is mainly divided into glossy blasting and pre-cracking blasting. In the process of blasting, in order to prevent the excessive damage caused by explosive blasting, it is often used to blast by means of uncoupled charges. In this study, LS-DYNA was used to establish a three-dimensional model for numerical simulation of blasting, and the whole process of blasting of uncoupled charge was reproduced. By simulating the damage cloud map, the pressure on the pore wall and the vibration speed of the pore wall are analyzed and compared with the non-coupling coefficients k=1.5, 2, 2.5, and 3, which provides a theoretical basis for the calculation of the parameters of glossy blasting and pre-cracking blasting.

Damage to Rocks by Eccentric Uncoupled Charge Explosion Loads

In the process of tunnel excavation, the blasting technology is one of the commonly used tunnel excavation methods. The blasting technology is mainly divided into smooth blasting and presplitting blasting. In the process of blasting, in order to prevent excessive damage caused by explosive blasting, the blasting is often carried out by means of uncoupled charging. In the previous studies, the explosive and the blast hole were mainly placed concentrically, while in the actual engineering, the charge often exists in the form of eccentricity. In this study, LS-DYNA is used to establish three-dimensional models of concentric charge and eccentric charge respectively for numerical simulation of blasting, and the whole process of uncoupled charge blasting is reproduced. Based on the damage cloud diagram, hole wall pressure and hole wall vibration velocity obtained by simulation, the damage caused by blasting under two different charging conditions is analyzed and compared.

Limbic Responses Following Shock Wave Exposure in Male and Female Mice.

Blast traumatic brain injury (bTBI) presents a serious threat to military personnel and often results in psychiatric conditions related to limbic system dysfunction. In this study, the functional outcomes for anxiety- and depressive-like behaviors and neuronal activation were evaluated in male and female mice after exposure to an Advanced Blast Simulator (ABS) shock wave. Mice were placed in a ventrally exposed orientation inside of the ABS test section and received primary and tertiary shock wave insults of approximately 15 psi peak pressure. Evans blue staining indicated cases of blood-brain barrier breach in the superficial cerebral cortex four, but not 24 h after blast, but the severity was variable. Behavioral testing with the elevated plus maze (EPM) or elevated zero maze (EZM), sucrose preference test (SPT), and tail suspension test (TST) or forced swim test (FST) were conducted 8 days–3.5 weeks after shock wave exposure. There was a sex difference, but no injury effect, for distance travelled in the EZM where female mice travelled significantly farther than males. The SPT and FST did not indicate group differences; however, injured mice were less immobile than sham mice during the TST; possibly indicating more agitated behavior. In a separate cohort of animals, the expression of the immediate early gene, c-Fos, was detected 4 h after undergoing bTBI or sham procedures. No differences in c-Fos expression were found in the cerebral cortex, but female mice in general displayed enhanced c-Fos activation in the paraventricular nucleus of the thalamus (PVT) compared to male mice. In the amygdala, more c-Fos-positive cells were observed in injured animals compared to sham mice. The observed sex differences in the PVT and c-Fos activation in the amygdala may correlate with the reported hyperactivity of females post-injury. This study demonstrates, albeit with mild effects, behavioral and neuronal activation correlates in female rodents after blast injury that could be relevant to the incidence of increased post-traumatic stress disorder in women.

An experimental and simulated investigation into the validity of unrestricted blast wave scaling models when applied to transonic flow in complex tunnel environments

Since the inception of high explosives as an industrial tool, significant efforts have been made to understand the flow of energy from an explosive into its surroundings to maximize work produced while minimizing damaging effects. Many tools have been developed over the past century, such as the Hopkinson–Cranz (H-C) Scaling Formula, to define blast wave behavior in open air. Despite these efforts, the complexity of wave dynamics has rendered blast wave prediction difficult under confinement, where the wave interacts with reflective surfaces producing complex time-pressure waveforms. This paper implements two methods to better understand blast overpressure propagation in a confined tunnel environment and establish whether scaled tests can be performed comparatively to costly full-scale experiments. Time–pressure waveforms were predicted using both a 1:10 scaled model and three-dimensional air blast simulations conducted in Ansys Autodyn. A comparison of the reduced scale model simulation with a full-scale blast simulation resulted in self-similar overpressure waveforms when employing the H-C scaling model. Experimental overpressure waveforms showed a high level of correlation between the reduced scale model and simulations. Additionally, peak overpressure, duration, and impulse values were found to match within tolerances that are highly promising for applying this methodology in future applications. Using this validated relationship, the simulated model and reduced scale tests were used to predict an overpressure waveform in a full-scale underground mine opening to within 2.12%, 2.91%, and 7.84% for peak overpressure, time of arrival, and impulse, respectively. This paper demonstrates the effectiveness of scaled, blast models when predicting blast wave parameters in a confined environment.

Blast Waves Cause Immune System Dysfunction and Transient Bone Marrow Failure in a Mouse Model.

Explosive devices, either conventional or improvised, are common sources of injuries during combat, civil unrest, and terror attacks, resulting in trauma from exposure to blast. A blast wave (BW), a near-instantaneous rise in pressure followed by a negative pressure, propagates through the body in milliseconds and can affect physiology for days/months after exposure. Epidemiological data show that blast-related casualties result in significantly higher susceptibility to wound infections, suggesting long-lasting immune modulatory effects from blast exposure. The mechanisms involved in BW-induced immune changes are poorly understood. We evaluated the effects of BW on the immune system using an established murine model. Animals were exposed to BWs (using an Advanced Blast Simulator), followed by longitudinally sampling for 14 days. Blood, bone marrow, and spleen were analyzed for changes in the 1) complete blood count (CBC), and 2) composition of bone marrow cells (BMC) and splenocytes, and 3) concentrations of systemic cytokines/chemokines. Our data demonstrate that BW results in transient bone marrow failure and long-term changes in the frequency and profile of progenitor cell populations. Viability progressively decreased in hematopoietic stem cells and pluripotent progenitor cells. Significant decrease of CD4+ T cells in the spleen indicates reduced functionality of adaptive immune system. Dynamic changes in the concentrations of several cytokines and chemokines such as IL-1α and IL-17 occurred potentially contributing to dysregulation of immune response after trauma. This work lays the foundation for identifying the potential mechanisms behind BW’s immunosuppressive effects to inform the recognition of this compromised status is crucial for the development of therapeutic interventions for infections to reduce recovery time of wounded patients injured by explosive devices.

Обоснование области и опыт применения однорядного взрывания в условиях повышенных требований к качеству полезного ископаемого

The paper justifies the application area of single-row blasting at nonmetallic deposits characterized with a complex structure and low cost of mineral resources, but with a high value of recoverable fractions. It describes the reasons for decreasing value of the end products mined in quarries developing marble reserves to produce microcalcite. Ways of upgrading the quality characteristics of rock preparation for excavation using single-row blasting are described for conditions of increased requirements towards the quality of minerals. Drilling and blasting plans are developed to achieve the required quality characteristics of rock crushing. A simulation of single-row blasting in conditions of varying parameters of the borehole grid and specific consumption of explosives has been carried out. The article presents the results of pilot blasting as well as technical and economic comparison of multi-row and single-row blasting in terms of maximized profitability of the mining company and minimized cost of the end product. The parameters of the mining system that are changed when single-row blasting is used are indicated.

Evaluation of Blast Simulation Methods for Modeling Blast Wave Interaction With Human Head.

Blast-induced traumatic brain injury (bTBI) research is crucial in asymmetric warfare. The finite element analysis is an attractive option to simulate the blast wave interaction with the head. The popular blast simulation methods are ConWep-based pure Lagrangian, Arbitrary-Lagrangian-Eulerian, and coupling method. This study examines the accuracy and efficiency of ConWep and coupling methods in predicting the biomechanical response of the head. The simplified cylindrical, spherical surrogates and biofidelic human head models are subjected to field-relevant blast loads using these methods. The reflected overpressures at the surface and pressures inside the brain from the head models are qualitatively and quantitatively evaluated against the available experiments. Both methods capture the overall trends of experiments. Our results suggest that the accuracy of the ConWep method is mainly governed by the radius of curvature of the surrogate head. For the relatively smaller radius of curvature, such as cylindrical or spherical head surrogate, ConWep does not accurately capture decay of reflected blast overpressures and brain pressures. For the larger radius of curvature, such as the biofidelic human head, the predictions from ConWep match reasonably well with the experiment. For all the head surrogates considered, the reflected overpressure-time histories predicted by the coupling method match reasonably well with the experiment. Coupling method uniquely captures the shadowing and union of shock waves governed by the geometry-driven flow dynamics around the head. Overall, these findings will assist the bTBI modeling community to judiciously select an objective-driven modeling methodology.

Experimental investigations of direct measurement of borehole wall pressure under decoupling charge

Decoupling charge is quite widely applied in smooth blasting, pre-splitting blasting, and bench blasting. The borehole wall pressure (BWP) is an indispensable condition for analyzing blasting action as it is the main initial parameter that determines the stress wave generated in the rock. In this study, a full-scale concrete model (4.0 m in length × 3.0 m in width × 1.6 m in height) with two boreholes was utilized to directly measure the BWP under decoupling charging. PVDF (polyvinylidene fluoride) gauges were employed as pressure-sensing devices to develop a technique for direct measuring high dynamic pressure due to its superior characteristics. The values of measured peak pressures of the borehole wall ranged from 1461 to 205 MPa within 0.1–1.1 m from the explosive charge end along the borehole axis. BWP of decoupling charge are responses to air shock wave loading and explosion gas loading, in which the responses near the explosive charge are the results of air shock wave and explosion gas working together, while the responses far from the charge are merely loaded by the air shock wave. The strain rates varied from 2.12 to 0.73 s−1 for the test range, which has confirmed that decoupling blast loading is a quasi-dynamic process. By fitting the experimental data, it is found that the peak value of BWP along the borehole axisdecreases as a power function with the increase of the distance from the explosive. The findings may be of great significance to mechanism analysis of rock blasting, scientific design of blasting schemes, and numerical simulation of rock blasting.

Thin-Walled Cylindrical Shell Storage Tank under Blast Impacts: Finite Element Analysis.

Thin-walled cylindrical shell storage tanks are pressure vessels in which the walls of the vessel have a thickness that is much smaller than the overall size of the vessel. These types of structures have global applications in various industries, including oil refineries and petrochemical plants. However, these storage tanks are vulnerable to fire and explosions. Therefore, a parametric study using numerical simulation was carried out, considering the internal liquid level, wall thickness, material yield strength, constraint conditions, and blast intensity, with a diameter of 100 m and height of 22.5 m under different blast loads using the finite element analysis method. The thickness of the tank wall is varied as 10 mm, 20 mm, 30 mm, and 40 mm, while the fill level of internal fluid is varied as 25, 50, 75, and 100%. The blast simulation was conducted using LS-DYNA software. The numerical results are then compared with analytical results. The effects of blast intensity, standoff distance, wall thickness, and fill level of internal fluid on the structural behaviour of the storage tank were investigated and discussed.