Study of Different Materials to Mitigate Blast Energy for the Tunnel Subjected to Buried Explosion

2021 ◽  
pp. 505-518
Author(s):  
Jagriti Mandal ◽  
Manmohan Dass Goel ◽  
Ajay Kumar Agarwal
Keyword(s):  
Blast Energy

Blast Mitigation Seat Analysis: Evaluation of Lumbar Compression Data Trends in 5th Percentile Female Anthropomorphic Test Device Performance Compared to 50th Percentile Male Anthropomorphic Test Device in Drop Tower Testing

2016 ◽  
Author(s):  
Kelly Bosch
Keyword(s):  
Lumbar Spine ◽  
Vertical Direction ◽  
Drop Tower ◽  
Blast Mitigation ◽  
Test Device ◽  
Military Population ◽  
Data Set ◽  
System Survivability ◽  
Blast Energy ◽  
Hybrid Iii

Although blast mitigation seats are historically designed to protect the 50th percentile male occupant based on mass, the scope of the occupant centric platform (OCP) Technology Enabled Capability Demonstration (TEC-D) within the U.S. Army Tank Automotive Research Development Engineering Center (TARDEC) Ground System Survivability has been expanded to encompass lighter and heavier occupants which represents the central 90th percentile of the military population. A series of drop tower tests were conducted on twelve models of blast energy-attenuating (EA) seats to determine the effects of vertical accelerative loading on ground vehicle occupants. Two previous technical publications evaluated specific aspects of the results of these drop tower tests on EA seats containing the three sizes of anthropomorphic test devices (ATDs) including the Hybrid III 5th percentile female, the Hybrid III 50th percentile male, and the Hybrid III 95th percentile male. The first publication addressed the overall trends of the forces, moments, and accelerations recorded by the ATDs when compared to Injury Assessment Reference Values (IARVs), as well as validating the methodology used in the drop tower evaluations1. Review of ATD data determined that the lumbar spine compression in the vertical direction could be used as the “go/no-go” indicator of seat performance. The second publication assessed the quantitative effects of Personal Protective Equipment (PPE) on the small occupant, as the addition of a helmet and Improved Outer Tactical Vest (IOTV) with additional gear increased the weight of the 5th percentile female ATD more than 50%2. Comparison of the loading data with and without PPE determined that the additional weight of PPE increased the overall risk of compressive injury to the lumbar and upper neck of the small occupant during an underbody blast event. Using the same data set, this technical paper aimed to evaluate overall accelerative loading trends of the 5th percentile female ATD when compared to those of the 50th percentile male ATD in the same seat and PPE configuration. This data trend comparison was conducted to gain an understanding of how seat loading may differ with a smaller occupant. The focus of the data analysis centered around the lumbar spine compression, as this channel was the most likely to exceed the IARV limit for the 5th percentile female ATD. Based on the previous analysis of this data set, the lightest occupant trends showed difficulty in protecting against lumbar compression injuries with respect to the 5th percentile female’s IARV, whereas the larger occupants experienced fewer issues in complying with their respective IARVs for lumbar compression. A review of pelvis acceleration was also conducted for additional kinetic insight into the motion of the ATDs as the seat strokes. This analysis included a review of how the weight and size of the occupant may affect the transmission of forces through a stroking seat during the vertical accelerative loading impulse.

scholarly journals Surface Interactions of Transonic Shock Waves with Graphene-Like Nanoribbons

Surfaces ◽  
2020 ◽  
Vol 3 (3) ◽  
pp. 505-515
Author(s):  
Shamal L. Chinke ◽  
Inderpal Singh Sandhu ◽  
Tejashree M. Bhave ◽  
Prashant S. Alegaonkar
Keyword(s):  
Split Hopkinson Pressure Bar ◽  
Interaction Mechanism ◽  
Chemical Vapor ◽  
Biomass Combustion ◽  
Structure Property ◽  
Hopkinson Pressure Bar ◽  
Blast Energy ◽  
Impulse Duration ◽  
Vapor Deposition Technique ◽  
The Impact

Graphene-like nanoribbons (GLNRs) were fabricated (length—20 μm; width—2 μm) and subjected to blast-like pulsed pressure >1.5 GPa (pulse speed ≈1 Mach, impulse duration, ≈µs) to examine the amount of absorption. GLNRs prepared by the chemical vapor deposition technique via controlled biomass combustion were subjected to investigate the structure–property characteristics using microspectroscopic techniques. Following this, GLNRs were employed to high strain rate (HSR) studies with the help of the technique known as split Hopkinson pressure bar (SHPB) to evaluate numerous dynamic parameters. The parameters were extracted from variations in the stress and strain rates. Their analysis provided insight into the damping response of blast energy within GLNRs. By and large, the impact generated modified the microstructure, exhibiting modifications in the number of layers, conjugated loops, and dynamic disorder. Signal processing analysis carried out for incident and transmitted impulse pressure revealed an interaction mechanism of shock wave with GLNR. Details are presented.

Ambient Gas Effects on Debris Formed During KrF Laser Ablation of Polyimide

1991 ◽  
Vol 236 ◽  
Author(s):  
Stephan Küper ◽  
James Brannon
Keyword(s):  
Laser Ablation ◽  
Blast Wave ◽  
Small Volume ◽  
Ambient Pressure ◽  
Wave Theory ◽  
Sufficient Time ◽  
Excimer Laser Ablation ◽  
Blast Energy ◽  
Ambient Gases ◽  
Krf Excimer Laser

AbstractThe surface debris that results from KrF excimer laser ablation of polyimide has been investigated as a function of the pressure. and atomic or molecular weight of several ambient gases: H2, He. Ne, air, Ar, Kr, and Xe. A linear relation between the measured debris radius and the inverse third root of the ambient pressure was found to exist, consistent with the predictions of blast wave theory. No measureable debris could be observed using helium or hydrogen gases up to 1 atm. similar to previous reports on helium. The derived value of the blast energy. equal to about 5% of the incident pulse energy, was used to estimate a nascent blast pressure of approximately 150 atm. By making the assumption that surface debris will form if the ablation fragments are confined in a “small” volume for a “sufficient” time, then conclusions from blast wave theory suggest how to decrease the amount of generated debris.

Heap leaching stimulation by blast energy

2019 ◽  
pp. 61-64
Author(s):  
V. N. Tyupin ◽  
Keyword(s):  
Heap Leaching ◽  
Blast Energy

Use of blast energy in excavating soils

1993 ◽  
Vol 27 (2) ◽  
pp. 66-71
Author(s):  
A. A. Vovk ◽  
V. G. Kravets ◽  
L. I. Demeshchuk
Keyword(s):  
Blast Energy

Blast Mitigation Seat Analysis: Assessment of the Effect of Personal Protective Equipment on the 5th Percentile Female Anthropomorphic Test Device Performance in Drop Tower Evaluations

2015 ◽  
Author(s):  
Kelly Bosch ◽  
Katrina Harris ◽  
David Clark ◽  
Risa Scherer ◽  
Joseph Melotik
Keyword(s):  
Personal Protective Equipment ◽  
Drop Tower ◽  
Protective Equipment ◽  
Blast Mitigation ◽  
Military Population ◽  
Small Female ◽  
Data Set ◽  
Technical Publication ◽  
Blast Energy ◽  
Hybrid Iii

To address the lack of knowledge on the quantitative effects of Personal Protective Equipment (PPE) on the small occupant, 55 drop tower tests were conducted and the resulting responses were evaluated. A previous technical publication evaluated the results of drop tower testing of twelve models of blast energy-attenuating seats1. That study assessed the data recorded from three sizes of anthropomorphic test devices, or ATDs, including the Hybrid III 5th percentile female, the Hybrid III 50th percentile male, and the Hybrid III 95th percentile male. The forces, moments, and accelerations from the ATDs were compared to Injury Assessment Reference Values (IARVs) to validate the drop tower methodology and to evaluate the appropriateness of the IARVs developed for the three occupant sizes. The data review revealed that the maximum lumbar compression loads recorded by the ATDs was an effective “go/no-go” criteria for judging seat performance, and that the 5th percentile female ATD, or small occupant, was the most difficult to pass the corresponding lumbar compression IARV. Additionally, the 5th percentile female ATD exceeded its corresponding IARV for upper neck compression, leading to the motivation for this study; the data set from the previous technical publication was used in this study. Historically, blast mitigation seats are designed to accommodate the average sized occupant, or 50th percentile male. Moving forward, there is a new emphasis on extending the protection afforded to the full military population, including the small female. The data presented in this paper seeks to determine the effect of PPE on the lumbar compression and upper neck loads for the small occupant.

scholarly journals Protective Headgear Attenuates Forces on the Inner Table and Pressure in the Brain Parenchyma During Blast and Impact: An Experimental Study Using a Simulant-Based Surrogate Model of the Human Head

2019 ◽  
Vol 142 (4) ◽  
Author(s):  
Austin Azar ◽  
Kapil Bharadwaj Bhagavathula ◽  
James Hogan ◽  
Simon Ouellet ◽  
Sikhanda Satapathy ◽  
...  
Keyword(s):  
Surrogate Model ◽  
Brain Injuries ◽  
Human Head ◽  
Brain Parenchyma ◽  
Blast Energy ◽  
Elevated Pressures ◽  
Blunt Impact ◽  
Head Protection ◽  
Impact Events ◽  
The Brain

Abstract Military personnel sustain head and brain injuries as a result of ballistic, blast, and blunt impact threats. Combat helmets are meant to protect the heads of these personnel during injury events. Studies show peak kinematics and kinetics are attenuated using protective headgear during impacts; however, there is limited experimental biomechanical literature that examines whether or not helmets mitigate peak mechanics delivered to the head and brain during blast. While the mechanical links between blast and brain injury are not universally agreed upon, one hypothesis is that blast energy can be transmitted through the head and into the brain. These transmissions can lead to rapid skull flexure and elevated pressures in the cranial vault, and, therefore, may be relevant in determining injury likelihood. Therefore, it could be argued that assessing a helmet for the ability to mitigate mechanics may be an appropriate paradigm for assessing the potential protective benefits of helmets against blast. In this work, we use a surrogate model of the head and brain to assess whether or not helmets and eye protection can alter mechanical measures during both head-level face-on blast and high forehead blunt impact events. Measurements near the forehead suggest head protection can attenuate brain parenchyma pressures by as much as 49% during blast and 52% during impact, and forces on the inner table of the skull by as much as 80% during blast and 84% during impact, relative to an unprotected head.

scholarly journals Experimental multiblast craters and ejecta — seismo-acoustics, jet characteristics, craters, and ejecta deposits and implications for volcanic explosions

2022 ◽  
Author(s):  
Ingo Sonder ◽  
Alison Graettinger ◽  
Tracianne Neilsen ◽  
Robin Matoza ◽  
Jacopo Taddeucci ◽  
...  
Keyword(s):  
Seismic Energy ◽  
Volcanic Eruptions ◽  
Maximum Size ◽  
Seismic Signal ◽  
Energy Estimates ◽  
First Order ◽  
Blast Energy ◽  
Jet Characteristics ◽  
Volcanic Explosions ◽  
Explosion Depth

Blasting experiments were performed that investigate multiple explosions that occur in quick succession in the ground and their effects on host material and atmosphere. Such processes are known to occur during volcanic eruptions at various depths, lateral locations, and energies. The experiments follow a multi-instrument approach in order to observe phenomena in the atmosphere and in the ground, and measure the respective energy partitioning. The experiments show significant coupling of atmospheric (acoustic)- and ground (seismic) signal over a large range of (scaled)distances (30--330\m, 1--10\(\m\J^{-1/3}\)). The distribution of ejected material strongly depends on the sequence of how the explosions occur. The overall crater sizes are in the expected range of a maximum size for many explosions and a minimum for one explosion at a given lateral location. The experiments also show that peak atmospheric over-pressure decays exponentially with scaled depth at a rate of \bar{d}_0 = 6.47x10^{-4} mJ^{-1/3}; at a scaled explosion depth of \(4x10^{-3} mJ^{-1/3} ca. 1% of the blast energy is responsible for the formation of the atmospheric pressure pulse; at a more shallow scaled depth of 2.75x10^{-3 \mJ^{-1/3} this ratio lies at ca. 5.5–7.5%. A first order consideration of seismic energy estimates the sum of radiated airborne and seismic energy to be up to 20\% of blast energy.

Gas hazard of explosives used in the mining industry

2021 ◽  
pp. 106-111
Author(s):  
S.A. Kozyrev ◽  
E.A. Vlasova
Keyword(s):  
Negative Impact ◽  
Mining Industry ◽  
Gaseous Detonation ◽  
Human Organism ◽  
Detonation Products ◽  
Underground Blasting ◽  
Gaseous Products ◽  
Blast Energy ◽  
Toxic Hazard ◽  
Hazardous Pollutants

Reducing emissions of hazardous pollutants that have a negative impact on the environment and human health has been approved as one of the strategic objectives of Russia's development. More than 90% of minerals in mined using blast energy. Despite an increase in the share of non-explosive component mixtures used in mining, blasting still poses a hazard to miners as the gaseous detonation products are potentially dangerous. The composition of blast gaseous products is extremely important in underground blasting because air exchange is difficult under these conditions and the blast products can contaminate the atmosphere of underground excavations, causing illness or poisoning of miners. Currently, there are no uniform requirements for obtaining information on the amount of gaseous blast products that would be hazardous to the human organism. Available documents do not contain information on the permissible amounts of toxic oxides per 1 kg of explosive detonated. The article compares the results of studying gas toxic hazard of industrial explosives obtained by different methods and based on different criteria.

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