scholarly journals Performance of Composite Metal Foam Armors against Various Threat Sizes

2020 ◽  
Vol 4 (4) ◽  
pp. 176
Author(s):  
Jacob Marx ◽  
Marc Portanova ◽  
Afsaneh Rabiei
Keyword(s):  
Kinetic Energy ◽  
Impact Energy ◽  
Metal Foam ◽  
Efficient Design ◽  
Thin Aluminum ◽  
Impact Energies ◽  
The Impact ◽  
Hollow Metal

The ballistic capabilities of composite metal foam (CMF) armors were experimentally tested against a 14.5 × 114 mm B32 armor-piercing incendiary (API) and compared to various sizes of armor-piercing (AP) ballistic threats, ranging from a 7.62 to 12.7 mm. Three different arrangements of layered hard armors were designed and manufactured using ceramic faceplates (in one layer, two layers or multiple tiles), a combination of ceramic and steel face sheets, with a single-layered CMF core, and a thin aluminum backing. The performance of various CMF armor designs against the 14.5 mm rounds are compared to each other and to the performance of the rolled homogeneous armor standard to identify the most efficient design for further investigations. The percentage of kinetic energy absorbed by the CMF layer in various armor arrangements and in tests against various threat sizes was calculated and compared. It appears that the larger the threat size, the more efficient the CMF layer will be due to a greater number of hollow metal spheres that are engaged in absorbing the impact energy. The results from this study will help to model and predict the performance of CMF armors against various threat sizes and impact energies.

${\rm C}^+_{60}$ IONS IN COLLISIONS WITH CRYSTALLINE SURFACES: KINEMATICS AND DYNAMICS

1996 ◽  
Vol 10 (01) ◽  
pp. 11-57 ◽  
Author(s):  
TH. LILL ◽  
H.-G. BUSMANN ◽  
F. LACHER ◽  
I.V. HERTEL
Keyword(s):  
Molecular Dynamics ◽  
Kinetic Energy ◽  
Impact Energy ◽  
Tangential Component ◽  
Measured Velocity ◽  
Surface Molecules ◽  
Molecular Dynamics Calculations ◽  
Impact Energies ◽  
Impact Angles ◽  
The Impact

Collisions of [Formula: see text] ions with surfaces of highly oriented pyrolytic graphite (HOPG), diamond (111) and heteroepitaxial fullerite films on mica in the impact energy range between 100 and 1500 eV are studied by mass, energy, and angle resolved time-of-flight mass spectrometry. For the graphite and diamond surfaces, highly inelastic scattering has been observed. The analysis of the velocity dependence of the scattered ions reveals that the normal and tangential component of the ion velocity have different significance for the collision dynamics. The normal component of the velocity appears to determine the amount of energy transferred into vibrational and deformational energy of the projectile and target. The final kinetic energy is independent of the impact energy for impact angles of ≈20° and impact energies between 140 and 450 eV. This observation can be explained by the existence of an upper bound of the final kinetic energy that is defined by the amount of energy stored in the deformed molecule without being deposited or destroyed. The tangential component is partially transformed into rotational energy of the [Formula: see text] in the collision with the surface, as may be explained by a simple rolling ball model. In contrast, scattering from heteroepitaxial fullerite films is nearly elastic for impact energies up to 230 eV and impact angles of about 20°. Additionally, the velocity distributions reveal a low velocity component. Its relative intensity increases with increasing impact energy and remains the only feature in the velocity distribution for impact energies higher than 290 eV. This component is due to sputtering of surface molecules. The angular dependent intensities of the fast ions exhibit a rich structure. This can be attributed to rainbow scattering, as confirmed by classical trajectory and molecular dynamics calculations with different levels of sophistication. These calculations also show that linear collision sequences along the closed packed rows of the fullerite surface may be generated as the result of the [Formula: see text] impact. A detailed study of these collision sequences by molecular dynamics calculations reveals that rainbow effects might be possible when these sequences are defocused due to thermal motion of the surface molecules. The contribution of this process to the measured velocity and angular distributions is discussed.

scholarly journals Breakage Susceptibility of Wheat and Triticale Seeds Related to Moisture Content and Impact Energy

2012 ◽  
Vol 45 (3) ◽  
pp. 5-13
Author(s):  
F. Shahbazi ◽  
A Dowlatshah ◽  
S. Valizadeh
Keyword(s):  
Moisture Content ◽  
Impact Energy ◽  
Mechanical Damage ◽  
Moisture Contents ◽  
Seed Damage ◽  
Significant Difference ◽  
Impact Energies ◽  
The Impact ◽  
Content Range ◽  
Wheat Seeds

Abstract Mechanical damage of seeds due to harvest, handling and other process is an important factor that affects the quality and quantity of seeds. Seed damage result in lower grain value, storability problem, and reduced seed germination and seedling vigor and subsequent yield of crops. The objective of this research was to determine the effects of moisture content and impact energy on the breakage susceptibility of wheat and triticale seeds. The experiments were conducted at five moisture contents of 7.5, 12, 17, 22 and 27% w.b. and at the impact energies of 0.05 and 0.1 J. The percentage of breakage of both wheat and triticale seeds increased as impact energy increased. The analysis of variance showed that there was a significant difference between breakage susceptibility of wheat and triticale seeds at the 1% probability level. Triticale seeds had more breakage than wheat seeds. For both wheat and triticale seeds as the moisture content of the seeds increased, the amount of the percentage breakage of seeds decreased as a polynomial. The average values of percentage breakage of wheat seeds decreased from 43.81 to 19.88% as the moisture content increased from 7.5 to 27%. Over this same moisture content range the percentage breakage of triticale seeds varied from 81.34 to 37.77%. Below the moisture contents of 17% for the wheat and 22% for the triticale the percentage breakage of seeds increased dramatically.

scholarly journals Dropped Object Impact Analysis Considering Frequency and Consequence for LNG-FPSO Topside Module

2021 ◽  
Vol 11 (16) ◽  
pp. 7753
Author(s):  
Kwangkook Lee ◽  
Hyunsu Ryu
Keyword(s):  
Impact Energy ◽  
Impact Analysis ◽  
Quantitative Risk Assessment ◽  
Production Area ◽  
The Difference ◽  
Offshore Industry ◽  
Impact Energies ◽  
The Impact ◽  
External Loads ◽  
Specific Orientation

Recently, quantitative risk assessment (QRA) has been widely used as a decision-making tool in the offshore industry. This study focused on analyzing dropped objects in the design of a modern offshore platform. A modified QRA procedure was developed for assessing production module protection against accidental external loads. Frequency and consequence analyses were performed using the developed QRA procedure. An exceedance curve was plotted, and a high-risk management item was derived through this process. In particular, simulations and experiments were used to verify the difference between the potential and impact energies according to drop orientation. When the object dropped in a specific orientation, the impact energy was confirmed to be up to 4.7 times greater than the potential energy. To reflect the QRA results in structural design, the proposed procedure should be used to calculate the maximum impact energy. The proposed procedure provides a step-by-step guide to assess the damage capacity of a production area as well as the damage frequency and consequences.

scholarly journals The Effect of Sorbitol and Conservation Period on The in Vitro Evolution of Solanum Tuberosum L. Plantlets

2012 ◽  
Vol 45 (3) ◽  
pp. 79-86
Author(s):  
Iustina Brînduşa Ciobanu ◽  
Dana Constantinovici
Keyword(s):  
Moisture Content ◽  
Impact Energy ◽  
Solanum Tuberosum L ◽  
Mechanical Damage ◽  
Moisture Contents ◽  
Significant Difference ◽  
Impact Energies ◽  
The Impact ◽  
Wheat Seeds

Abstract Mechanical damage of seeds due to harvest, handling and other process is an important factor that affects the quality and quantity of seeds. Seed damage result in lower grain value, storability problem, and reduced seed germination and seedling vigor and subsequent yield of crops. The objective of this research was to determine the effects of moisture content and impact energy on the breakage susceptibility of wheat and triticale seeds. The experiments were conducted at five moisture contents of 7.5, 12, 17, 22 and 27% w.b. and at the impact energies of 0.05 and 0.1 J. The percentage of breakage of both wheat and triticale seeds increased as impact energy increased. The analysis of variance showed that there was a significant difference between breakage susceptibility of wheat and triticale seeds at the 1% probability level. Triticale seeds had more breakage than wheat seeds. For both wheat and triticale seeds as the moisture content of the seeds increased, the amount of the percentage breakage of seeds decreased as a polynomial. The average values of percentage breakage of wheat seeds decreased from 43.81 to 19.88% as the moisture content increased from 7.5 to 27%. Over this same moisture content range the percentage breakage of triticale seeds varied from 81.34 to 37.77%. Below the moisture contents of 17% for the wheat and 22% for the triticale the percentage breakage of seeds increased dramatically.

Abrasion regimes in fluvial bedrock incision

Geology ◽  
2021 ◽  
Author(s):  
Alexander R. Beer ◽  
Michael P. Lamb
Keyword(s):  
Impact Energy ◽  
Fragment Size ◽  
Bedrock Rivers ◽  
Rock Fragments ◽  
River Incision ◽  
Energy Scaling ◽  
Wide Range ◽  
Bedrock Erosion ◽  
Impact Energies ◽  
The Impact

River incision into bedrock drives landscape evolution and couples surface changes to climate and tectonics in uplands. Mechanistic bedrock erosion modeling has focused on plucking—the hydraulic removal of large loosened rock fragments—and on abrasion—the slower fracturing-driven removal of rock due to impacts of transported sediment—which produces sand- or silt-sized fragments at the mineral grain scale (i.e., wear). An abrasion subregime (macro-abrasion) has been hypothesized to exist under high impact energies typical of cobble or boulder transport in mountain rivers, in which larger bedrock fragments can be generated. We conducted dry impact abrasion experiments across a wide range of impact energies and found that gravel-sized fragments were generated when the impact energy divided by squared impactor diameter exceeded 1 kJ/m2. However, the total abraded volume followed the same kinetic-energy scaling regardless of fragment size, holding over 13 orders of magnitude in impact energy and supporting a general abrasion law. Application to natural bedrock rivers shows that many of them likely can generate large fragments, especially in steep mountain streams and during large floods, transporting boulders in excess of 0.6 m diameter. In this regime, even single impacts can cause changes in riverbed topography that may drive morphodynamic feedbacks.

Investigations on Dynamic Energy Absorption Behavior of Metal Foam

2016 ◽  
Vol 715 ◽  
pp. 192-197
Author(s):  
Geng Luo ◽  
Pu Xue
Keyword(s):  
Shock Wave ◽  
Kinetic Energy ◽  
Internal Energy ◽  
Energy Absorption ◽  
Metal Foam ◽  
Local Maximum ◽  
Energy Behavior ◽  
Impact Side ◽  
The Impact ◽  
Maximum Minimum

In this study, the dynamic energy absorption behavior of metal foam is investigated. A 3D Voronoi numerical model is established. Uniaxial compression under quasi-static and impact with velocities in the range of 10m/s to 200m/s are implemented, respectively, to investigate the energy behavior. During the impact process, the impact energy is transferred into kinetic energy and the internal energy. The kinetic energy varies with fluctuation due to the propagation and reflection of plastic shock wave. When the plastic shock wave arrives at the impact side or support side, the rate of internal energy absorption increases, and the kinetic energy possesses a local maximum/minimum value. The dynamic internal energy is obvious higher than quasi-static internal energy, due to the region behind the wave front is compacted tightly resulted from the plastic shock wave.

The flexural behaviors of the impacted composite single-lap adhesive joints

2015 ◽  
Vol 22 (5) ◽  
Author(s):  
Emin Ergun ◽  
Hasan Çallioğlu
Keyword(s):  
Experimental Study ◽  
Impact Energy ◽  
Energy Levels ◽  
Composite Plates ◽  
Lap Joints ◽  
Adhesive Joints ◽  
Single Lap Joints ◽  
Impact Tests ◽  
Impact Energies ◽  
The Impact

AbstractThis experimental study deals with the flexural behaviors of composite single-lap adhesive joints after impact tests. Increasing impact energies are applied at the center of the composite plates having three different overlap lengths. It is shown that the overlap lengths and impact energy levels affect considerably the impact responses of the composite single-lap joints. It is also shown that the bending stiffness of the composite increases with increasing overlap length. For this reason, after the impact tests, how these effects influence the flexural behaviors of the impacted composite lap joints was also investigated. The flexural loads of the impacted and non-impacted composite single-lap joints were determined and compared with each other. It is shown that the residual flexural loads after impact increase with increasing overlap lengths but decrease with increasing impact energy.

scholarly journals An Experimental Investigation on the Impact Behaviour of Glass/Epoxy and Hybrid Composite Plates

2009 ◽  
Vol 18 (4) ◽  
pp. 096369350901800 ◽  
Author(s):  
Metin Sayer ◽  
Numan B. Bektaş ◽  
Onur Sayman ◽  
Muzaffer Topçu
Keyword(s):  
Cross Sections ◽  
Impact Energy ◽  
Hybrid Composite ◽  
Composite Plates ◽  
Glass Carbon ◽  
Extent Of Damage ◽  
Impact Energies ◽  
The Impact ◽  
The Relationship ◽  
Energy Profiling

In this study, the impact behaviours of glass/epoxy and hybrid (glass-carbon/epoxy) composite plates have been investigated experimentally. The increasing impact energy was performed on composite plates until complete perforation of samples. An energy profiling diagram, showing the relationship between impact energy and absorbed energy, was used together with load-deflection curves to determine the penetration and perforation thresholds of composite plates. The failure processes of damaged specimens for different impact energies were evaluated by comparing load-deflection curves and images of damaged samples taken from impacted sides and non-impacted sides. Cross-sections of damaged specimens for both plates were also inspected visually and discussed to assess the extent of damage, such as fibre fracture in layers, expansion of delaminations between adjacent layers. The perforation threshold of hybrid composite impacted from surface with carbon fibres was found approximately 30% and 15% higher than those of surface with glass fibres of hybrid plates and glass/epoxy plates, respectively.

Development of Impact Energy Distribution of Various Abrasives during Cyclic Impact/Abrasion Testing

2017 ◽  
Vol 267 ◽  
pp. 234-242 ◽  
Author(s):  
Lukas Widder ◽  
Markus Varga ◽  
Karl Adam ◽  
Andreas Kuttner
Keyword(s):  
Energy Distribution ◽  
Impact Energy ◽  
Fracture Behaviour ◽  
Energy Distributions ◽  
Abrasive Particles ◽  
Size Fractions ◽  
Cyclic Impact ◽  
Impact Energy Distribution ◽  
Impact Energies ◽  
The Impact

In heavy industries like mining or steel production vast amounts of loose materials need to be transported, relocated or otherwise processed. During these routines severe stresses are applied on heavy machinery components such as excavator grabs and clamshells, which ultimately lead to excessive wear. The dominant wear mechanisms under such conditions are impact and abrasion. The focus of this paper is to investigate the fracture behaviour of various abrasives as experienced under real application in the steel industry. Breaking events of abrasive particles affect the impact energies on tool equipment. The Cyclic Impact/Abrasion Test rig (CIAT) was applied to investigate the stability and fracture behaviour of the abrasives. Rotating counter bodies made of martensitic quenched and tempered steel were used to generate impact events on loose abrasive particles. After certain time intervals the abrasives were screened and particle size fractions documented. Impact energy is strongly dependent on size and density, as well as fragility and cracking of particles. As fracturing events diminish particle dimensions and shift size distributions to lower size fractions, each abrasive showed a distinctive impact energy distribution over the course of the test duration. Impact energy distributions of abrasives were correlated to wear rates of the steel samples for each abrasive used. The results indicate a distinct behaviour of each abrasive, yielding certain impact energy distributions. Depending on processing specific abrasive goods in actual applications, impact energies and associated wear loss can differ significantly.

Impact Energy of Gas-Solid Flows

2014 ◽  
Vol 628 ◽  
pp. 323-326
Author(s):  
Hai Ping Zhu
Keyword(s):  
Blast Furnace ◽  
Energy Dissipation ◽  
Kinetic Energy ◽  
Flow Rate ◽  
Impact Energy ◽  
Particle Interactions ◽  
Governing Equations ◽  
Solid Flow ◽  
Friction Energy ◽  
Impact Energies

The models for impact energies of gas-solid flows are proposed based on the governing equations of the flows, and then applied to investigate the energies of the gas-solid flow in a model blast furnace (BF). The kinetic energy, contact and friction energy dissipations, and energy dissipation from fluid – particle interactions are examined. The effect of solid flow rate on the energies is also studied. The results indicate that the distributions of the energies are related to the flow pattern of the solid flow.

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