scholarly journals Penetration of Energised Metal Fragments to Porcine Thoracic Tissues

2021 ◽  
Author(s):  
Thuy-Tien Nguyen ◽  
John Breeze ◽  
Spyros D Masouros
Keyword(s):  
Impact Velocity ◽  
Medical Emergency ◽  
Common Mechanism ◽  
Public Infrastructure ◽  
Residual Velocity ◽  
Gas Gun ◽  
Numerical Tools ◽  
Inherent Vulnerability ◽  
Explosive Devices ◽  
The Impact

Abstract Energised fragments from explosive devices have been the most common mechanism of injury to both military personnel and civilians in recent conflicts and terrorist attacks. Fragments that penetrate into the thoracic cavity are strongly associated with death due to the inherent vulnerability of the underlying structures. The aim of this study was to investigate the impact of fragment-simulating projectiles (FSPs) to tissues of the thorax in order to identify the thresholds of impact velocity for perforation through these tissues and the resultant residual velocity of the FSPs. A gas-gun system was used to launch 0.78-g cylindrical and 1.13-g spherical FSPs at intact porcine thoracic tissues from different impact locations. The sternum and rib bones were the most resistant to perforation, followed by the scapula and intercostal muscle. For both FSPs, residual velocity following perforation was linearly proportional to impact velocity. These findings can be used in the development of numerical tools for predicting the medical outcome of explosive events, which in turn can inform the design of public infrastructure, of personal protection, and of medical emergency response.

Selection of Densification Strain to Predict Dynamic Crushing Stress at High Impact Velocity of ALPORAS Aluminium Foam

2014 ◽  
Vol 626 ◽  
pp. 383-388 ◽  
Author(s):  
Mohd Azman Yahaya ◽  
Dong Ruan ◽  
Guo Xing Lu ◽  
Matthew S. Dargusch ◽  
Tong Xi Yu
Keyword(s):  
Impact Velocity ◽  
Strain Curve ◽  
High Impact ◽  
Aluminium Foam ◽  
Gas Gun ◽  
High Impact Velocity ◽  
Velocity Prediction ◽  
Blast Loadings ◽  
The Impact ◽  
Dynamic Crushing

Cellular material such as aluminium foam has been considered as a potential material for energy absorption upon impact and blast loadings. One of the most important properties that contribute to this feature is the densification strain. At high impact velocity, prediction of the densification strain from quasi-static engineering stress-strain curve has been found inadequate. Furthermore, theoretical prediction using the equation proposed by Reid et al. always over-predicts the dynamic crushing stress. Formation of the shock wave at high impact velocity is believed to further increase the densification level of the foam. However, this effect is disregarded when determining the densification strain quasi-statically. The present study aims to address this issue by determining the densification strain experimentally from impact tests. Forty cylindrical aluminium foams with three different lengths were used as projectiles and were fired towards a rigid load cell by using a gas gun. The peak forces generated from the impact were recorded and analysed. The experimental densification strains were determined physically by measuring the deformation of the foam projectiles after the tests. It is concluded that, at high impact velocity, the densification strain varies with the initial impact velocity. Therefore an appropriate value of densification strain needs to be used in the equation of dynamic crushing stress for a better approximation.

Simulation Studies on the Influence of Impact Velocity on the PELE Penetrated and Broken Reinforced Concrete

2013 ◽  
Vol 690-693 ◽  
pp. 3108-3111 ◽  
Author(s):  
Xiao Jun Ye ◽  
Zhong Hua Du ◽  
Chuan Hui Hu ◽  
Cheng Jun Song ◽  
Xiao Sheng
Keyword(s):  
Finite Element Method ◽  
Reinforced Concrete ◽  
Impact Velocity ◽  
Simulation Studies ◽  
Residual Velocity ◽  
Software Simulation ◽  
Definite Effect ◽  
Simulation Results ◽  
The Impact ◽  
Good Agreement

In order to study the effect of the impact velocity for the penetrator with enhanced lateral effect (PELE) penetrating reinforced concrete (RC) targets, penetration of PELE filled nylon against RC target using the different velocity is simulated by LS-DYNA finite element method software. Simulation shows that the impact velocity have definite effect on broken RC. On condition of PELE having penetrated target, with farther increase of impact velocity, the area of PELE broken RC on the direction of decrease firstly and augmentation thereafter, the residual velocity after penetrating target is less at the same time; Take into account validity of lateral effect and general launching condition, selecting the impact velocity at the range of 800 m/s-1300 m/s is suitable for PELE broken RC. The simulation results are in good agreement with those of the experiments.

Shear Wave Attenuation and its Micro-Mechanism of Polymers

2013 ◽  
Vol 446-447 ◽  
pp. 249-253
Author(s):  
Zhi Ping Tang ◽  
Ting Li
Keyword(s):  
Shear Wave ◽  
Impact Velocity ◽  
Shear Failure ◽  
Wave Attenuation ◽  
Optical Microscope ◽  
Shear Loading ◽  
Impact Surface ◽  
Gas Gun ◽  
Electro Magnetic ◽  
The Impact

The impact shear response of crystallized polypropylene under combined compression and shear loading was studied by using an inclined gas gun and electro-magnetic particle velocity gauges. The experimental results show that the transverse wave velocity increases nonlinearly with the impact velocity, indicating its shear behavior is strongly related to the hydrostatic pressure. Remarkable shear wave attenuation occurs near the impact surface when the impact velocity and inclination angle reach the critical value. The micro-observation of recovered samples with a polarized optical microscope reveals that there exists a melting layer of about 2-3μm thick, i.e. adiabatic shear failure layer, very near the impact surface (about 5μm) which causes the shear wave attenuation.

Ejecta Size Distribution Resulting from Hypervelocity Impacts between Aluminum Alloys

2014 ◽  
Vol 566 ◽  
pp. 338-343 ◽  
Author(s):  
Kenta Nozaki ◽  
Masahiro Nishida ◽  
Koichi Hayashi ◽  
Sunao Hasegawa
Keyword(s):  
Aluminum Alloy ◽  
Impact Velocity ◽  
High Speed ◽  
Video Camera ◽  
Distribution Model ◽  
Cumulative Number ◽  
Gas Gun ◽  
High Speed Video Camera ◽  
The Impact ◽  
Japan Aerospace Exploration Agency

We investigated the effects of impact velocity on ejecta size when aluminum alloy 2017-T4 spheres with a diameter of 3.2 mm impacted aluminum alloy 6061-T6 targets with a thickness of 30 mm at velocities of 2 to 7 km/s. We used a two-stage light-gas gun at the Institute of Space and Astronautical Science (ISAS)/Japan Aerospace Exploration Agency (JAXA). To examine the scattering angles of the ejecta, the following was placed 50 mm in front of the target: a witness plate (150 mm × 150 mm, 2 mm in thickness) made of copper with a hole of 30 mm. The ejection behaviors of fragments were observed using a high-speed video camera. The size distributions of the ejecta were examined in detail. The cumulative number of ejecta was proportional to the square of the impact velocity; in other words, to the impact energy of the projectiles. An experimental formula was created by curve fitting of the cumulative number distribution of the projected areas to a bilinear exponential distribution model when the aluminum alloy spheres struck the aluminum alloy targets.

scholarly journals Predicting pathogenic non-coding SVs disrupting the 3D genome in 1646 whole cancer genomes using multiple instance learning

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marleen M. Nieboer ◽  
Luan Nguyen ◽  
Jeroen de Ridder
Keyword(s):  
Multiple Instance Learning ◽  
Cancer Diagnostics ◽  
Common Mechanism ◽  
Open Chromatin ◽  
Driver Genes ◽  
3D Genome ◽  
Whole Genomes ◽  
Cancer Genomes ◽  
Cancer Types ◽  
The Impact

AbstractOver the past years, large consortia have been established to fuel the sequencing of whole genomes of many cancer patients. Despite the increased abundance in tools to study the impact of SNVs, non-coding SVs have been largely ignored in these data. Here, we introduce svMIL2, an improved version of our Multiple Instance Learning-based method to study the effect of somatic non-coding SVs disrupting boundaries of TADs and CTCF loops in 1646 cancer genomes. We demonstrate that svMIL2 predicts pathogenic non-coding SVs with an average AUC of 0.86 across 12 cancer types, and identifies non-coding SVs affecting well-known driver genes. The disruption of active (super) enhancers in open chromatin regions appears to be a common mechanism by which non-coding SVs exert their pathogenicity. Finally, our results reveal that the contribution of pathogenic non-coding SVs as opposed to driver SNVs may highly vary between cancers, with notably high numbers of genes being disrupted by pathogenic non-coding SVs in ovarian and pancreatic cancer. Taken together, our machine learning method offers a potent way to prioritize putatively pathogenic non-coding SVs and leverage non-coding SVs to identify driver genes. Moreover, our analysis of 1646 cancer genomes demonstrates the importance of including non-coding SVs in cancer diagnostics.

scholarly journals Air mediates the impact of a compliant hemisphere on a rigid smooth surface

Soft Matter ◽  
2021 ◽  
Author(s):  
Siqi Zheng ◽  
Sam Dillavou ◽  
John M. Kolinski
Keyword(s):  
Elastic Body ◽  
Elastic Properties ◽  
Impact Velocity ◽  
Solid Surface ◽  
High Speed ◽  
Smooth Surface ◽  
High Speed Imaging ◽  
The Impact ◽  
Rigid Smooth

When a soft elastic body impacts upon a smooth solid surface, the intervening air fails to drain, deforming the impactor. High-speed imaging with the VFT reveal rich dynamics and sensitivity to the impactor's elastic properties and the impact velocity.

scholarly journals A smart passive MR damper with a hybrid powering system for impact mitigation: An experimental study

2021 ◽  
pp. 1045389X2098808
Author(s):  
S. Jin ◽  
L. Deng ◽  
J. Yang ◽  
S. Sun ◽  
D. Ning ◽  
...  
Keyword(s):  
Impact Velocity ◽  
Mr Damper ◽  
Damping Force ◽  
Softening Effect ◽  
Impact Speed ◽  
Impact Mitigation ◽  
Passive Damper ◽  
Comparison Results ◽  
Wide Range ◽  
The Impact

This paper presents a smart passive MR damper with fast-responsive characteristics for impact mitigation. The hybrid powering system of the MR damper, composed of batteries and self-powering component, enables the damping of the MR damper to be negatively proportional to the impact velocity, which is called rate-dependent softening effect. This effect can keep the damping force as the maximum allowable constant force under different impact speed and thus improve the efficiency of the shock energy mitigation. The structure, prototype and working principle of the new MR damper are presented firstly. Then a vibration platform was used to characterize the dynamic property and the self-powering capability of the new MR damper. The impact mitigation performance of the new MR damper was evaluated using a drop hammer and compared with a passive damper. The comparison results demonstrate that the damping force generated by the new MR damper can be constant over a large range of impact velocity while the passive damper cannot. The special characteristics of the new MR damper can improve its energy dissipation efficiency over a wide range of impact speed and keep occupants and mechanical structures safe.

Effect of Particle Impact Velocity on Cone Crack Shape in Ceramic Material

2005 ◽  
Vol 297-300 ◽  
pp. 1321-1326 ◽  
Author(s):  
Sang Yeob Oh ◽  
Hyung Seop Shin
Keyword(s):  
Impact Velocity ◽  
Computational Simulation ◽  
Back Surface ◽  
Particle Impact ◽  
Cone Crack ◽  
Crack Shape ◽  
The Impact ◽  
Particle Impact Velocity ◽  
Sic Particle ◽  
Ring Cracks

The damage behaviors induced in a SiC by a spherical particle impact having a different material and size were investigated. Especially, the influence of the impact velocity of a particle on the cone crack shape developed was mainly discussed. The damage induced by a particle impact was different depending on the material and the size of a particle. The ring cracks on the surface of the specimen were multiplied by increasing the impact velocity of a particle. The steel particle impact produced the larger ring cracks than that of the SiC particle. In the case of the high velocity impact of the SiC particle, the radial cracks were generated due to the inelastic deformation at the impact site. In the case of the larger particle impact, the morphology of the damages developed were similar to the case of the smaller particle one, but a percussion cone was formed from the back surface of the specimen when the impact velocity exceeded a critical value. The zenithal angle of the cone cracks developed into the SiC decreased monotonically as the particle impact velocity increased. The size and material of a particle influenced more or less on the extent of the cone crack shape. An empirical equation was obtained as a function of impact velocity of the particle, based on the quasi-static zenithal angle of the cone crack. This equation will be helpful to the computational simulation of the residual strength in ceramic components damaged by the particle impact.

Debris/Micrometeoroid Impacts and Synergistic Effects on Spacecraft Materials

MRS Bulletin ◽  
2010 ◽  
Vol 35 (1) ◽  
pp. 41-47 ◽  
Author(s):  
E. Grossman ◽  
I. Gouzman ◽  
R. Verker
Keyword(s):  
Space Debris ◽  
Synergistic Effects ◽  
Degradation Mechanism ◽  
Space Environment ◽  
Materials Properties ◽  
Gas Gun ◽  
Naturally Occurring ◽  
Space Activity ◽  
The Impact ◽  
Debris Impact

AbstractIn the last 40 years, the increased space activity created a new form of space environment of hypervelocity objects—space debris—that have no functional use. The space debris, together with naturally occurring ultrahigh velocity meteoroids, presents a significant hazard to spacecraft. Collision with space debris or meteoroids might result in disfunction of external units such as solar cells, affecting materials properties, contaminating optical devices, or destroying satellites. The collision normally results in the formation of additional debris, increasing the hazard for future missions. The hypervelocity debris effect is studied by retrieving materials from space or by using ground simulation facilities. Simulation facilities, which include the light gas gun and Laser Driven Flyer methods, are used for studying the materials degradation due to debris impact. The impact effect could be accelerated when occurring simultaneously with other space environment components, such as atomic oxygen, ultraviolet, or x-ray radiation. Understanding the degradation mechanism might help in developing materials that will withstand the increasing hazard from the space debris, allowing for longer space missions. The large increase in space debris population and the associated risk to space activity requires significant measures to mitigate this hazard. Most current efforts are being devoted to prevention of collisions by keeping track of the larger debris and avoiding formation of new debris.

Sign in / Sign up

Export Citation Format

Share Document