A Numerical Study of Ballistic Resistance of a Single Layer Ceramic Target

2021 ◽  
pp. 235-247
Author(s):  
M. K. Khan ◽  
M. A. Iqbal ◽  
N. K. Gupta
Keyword(s):  
Numerical Study ◽  
Single Layer ◽  
Ceramic Target ◽  
Ballistic Resistance

scholarly journals Enhanced ultraviolet absorption in graphene by aluminum and magnesium hole-arrays

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xueling Cheng ◽  
Yunshan Wang
Keyword(s):  
Numerical Study ◽  
Uv Spectroscopy ◽  
Single Layer ◽  
Hybrid Structure ◽  
Uv Absorption ◽  
Single Layer Graphene ◽  
Visible Range ◽  
Uv Spectrum ◽  
Hole Arrays ◽  
Uv Range

AbstractOptoelectronic devices in the UV range have many applications including deep-UV communications, UV photodetectors, UV spectroscopy, etc. Graphene has unique exciton resonances, that have demonstrated large photosensitivity across the UV spectrum. Enhancing UV absorption in graphene has the potential to boost the performance of the various opto-electronic devices. Here we report numerical study of UV absorption in graphene on aluminum and magnesium hole-arrays. The absorption in a single-layer graphene on aluminum and magnesium hole-arrays reached a maximum value of 28% and 30% respectively, and the absorption peak is tunable from the UV to the visible range. The proposed graphene hybrid structure does not require graphene to be sandwiched between different material layers and thus is easy to fabricate and allows graphene to interact with its surroundings.

scholarly journals Numerical Study on Crack Distributions of the Single-Layer Building under Seismic Waves

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-16
Author(s):  
Fenghui Dong ◽  
Zhipeng Zhong ◽  
Jin Cheng
Keyword(s):  
Seismic Waves ◽  
Numerical Study ◽  
Single Layer ◽  
Experimental Tests ◽  
Masonry Structure ◽  
Original Model ◽  
Dynamic Responses ◽  
Masonry Structures ◽  
Reinforced Masonry ◽  
Longitudinal Cracks

This paper conducts a numerical simulation of the antiseismic performance for single-layer masonry structures, completes a study on crack distributions and detailed characteristics of masonry structures, and finally verifies the correctness of the numerical model by experimental tests. This paper also provides a reinforced proposal to improve the antiseismic performance of single-layer masonry structures. Results prove that the original model suffers more serious damage than the reinforced model; in particular, longitudinal cracks appear on bottoms of two longitudinal walls in the original model, while these cracks appear later in the reinforced model; a lot of cracks appear on the door hole of the original model, and no crack appears in the reinforced model till the end of seismic waves; seismic damage of walls in the reinforced model is obviously lighter than that in the original model; dynamic responses at all observed points of the reinforced masonry are obviously less than those of the original model. Strains at all positions of the reinforced model are obviously smaller than those of the original model. From macroscopic and microscopic perspectives, the computational results prove that the reinforced proposal proposed in this paper can effectively improve the antiseismic performance of the masonry structure.

Recombination zone and efficiency in bipolar single layer light-emitting devices: a numerical study

2008 ◽  
Vol 93 (2) ◽  
pp. 559-564 ◽  
Author(s):  
Ying-Quan Peng ◽  
Qing-Sen Yang ◽  
Hong-Wei Xing ◽  
Xun-Shuan Li ◽  
Jian-Ting Yuan ◽  
...  
Keyword(s):  
Numerical Study ◽  
Single Layer ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Recombination Zone

Effect of Helmet Pads on the Load Transfer to Head Under Blast Loadings

2014 ◽  
Author(s):  
Timothy G. Zhang ◽  
Sikhanda S. Satapathy
Keyword(s):  
Load Transfer ◽  
Numerical Study ◽  
Single Layer ◽  
Blast Loading ◽  
Performance Criterion ◽  
Ballistic Performance ◽  
Commercial Code ◽  
Head Assembly ◽  
Computational Simplicity ◽  
Blast Loadings

Recent wars have highlighted the need to better protect dismounted soldiers against emerging blast and ballistic threats. Current helmets are designed to meet ballistic performance criterion. Therefore, ballistic performance of helmets has received a lot of attention in the literature. However, blast load transfer/mitigation has not been well understood for the helmet/foam pads. The pads between the helmet and head can not only absorb energy, but also produce more comfort to the head. The gap between the helmet and head due to the pads helps prevent or delay the contact between helmet shell and the head. However, the gap between the helmet shell and the head can produce underwash effect, where the pressure can be magnified under blast loading. In this paper, we report a numerical study to investigate the effects of foam pads on the load transmitted to the head under blast loading. The ALE module in the commercial code, LS-DYNA was used to model the interactions between fluid (air) and the structure (helmet/head assembly). The ConWep function was used to apply blast loading to the air surrounding the helmet/head. Since we mainly focus on the load transfer to the head, four major components of the head were modeled: skin, bone, cerebrospinal fluid (CSF) and brain. The foam pads in fielded helmets are made of a soft and a hard layer. We used a single layer with the averaged property to model both of those layers for computational simplicity. Sliding contact was defined between the foam pads and the helmet. A parametric study was carried out to understand the effects of material parameters and thickness of the foam pads.

scholarly journals Numerical Study of an Ultra-Broadband All-Silicon Terahertz Absorber

2020 ◽  
Vol 10 (2) ◽  
pp. 436 ◽  
Author(s):  
Jinfeng Wang ◽  
Tingting Lang ◽  
Tingting Shen ◽  
Changyu Shen ◽  
Zhi Hong ◽  
...  
Keyword(s):  
Numerical Study ◽  
Structural Parameters ◽  
Impedance Matching ◽  
Single Layer ◽  
Transverse Magnetic ◽  
Absorption Efficiency ◽  
Absorption Mechanism ◽  
Loss Mechanism ◽  
Perfect Absorption ◽  
Terahertz Absorber

In this article we present and numerically investigate a broadband all-silicon terahertz (THz) absorber which consists of a single-layer periodic array of a diamond metamaterial layer placed on a silicon substrate. We simulated the absorption spectra of the absorber under different structural parameters using the commercial software Lumerical FDTD solutions, and analyzed the absorption mechanism from the distribution of the electromagnetic fields. Finally, the absorption for both transverse electric (TE) and transverse magnetic (TM) polarizations under different incident angles from 0 to 70° were investigated. Herein, electric and magnetic resonances are proposed that result in perfect broadband absorption. When the absorber meets the impedance matching principle in accordance with the loss mechanism, it can achieve a nearly perfect absorption response. The diamond absorber exhibits an absorption of ~100% at 1 THz and achieves an absorption efficiency >90% within a bandwidth of 1.3 THz. In addition, owing to the highly structural symmetry, the absorber has a polarization-independent characteristic. Compared with previous metal–dielectric–metal sandwiched absorbers, the all-silicon metamaterial absorbers can avoid the disadvantages of high ohmic losses, low melting points, and high thermal conductivity of the metal, which ensure a promising future for optical applications, including sensors, modulators, and photoelectric detection devices.

Numerical Study on the Ballistic Impact on Lightweight Composite Armour

2014 ◽  
Vol 670-671 ◽  
pp. 824-828 ◽  
Author(s):  
Jiang Ren Lu ◽  
Xin Li Sun ◽  
Xing Hui Cai ◽  
San Qiang Dong ◽  
Guo Liang Wang
Keyword(s):  
Numerical Study ◽  
Thickness Ratio ◽  
Ceramic Fiber ◽  
Sandwich Composite ◽  
Fiber Layer ◽  
Ballistic Resistance ◽  
Finite Element Software ◽  
Steel Target ◽  
Potential Component ◽  
Ballistic Limit Velocity

A lightweight sandwich composite armours has been established by comparing the ballistic resistance of the potential component materials. The ballistic-resistance properties of the armours under impacting by the bullet with 12.7mm diameter are also numerically investigated by using finite element software LS-DYNA. Numerical modeling is used to obtain an estimate for the ballistic limit velocity (V50) and simulate penetration processes. The focus is placed on the energy absorption capabilities of different component layers with same density per unit area. The influence of stacking sequence and thickness ratio of ceramic/fiber layer has been analyzed in detail. Results indicate that the composite armour having optimal thickness ratio of ceramic/fiber layer in the same density and its mass is 29% lighter than of 4340 steel target.

Numerical Study on Controllable Multi-Band Microwave Metamaterial Absorbers

2011 ◽  
Vol 239-242 ◽  
pp. 1260-1264
Author(s):  
Wei Wei Ji ◽  
Tao Wang ◽  
Yan Nie ◽  
Rong Zhou Gong
Keyword(s):  
Numerical Study ◽  
Impedance Matching ◽  
Single Layer ◽  
Surface Current ◽  
Metamaterial Absorber ◽  
Band Absorption ◽  
Different Dimensions ◽  
Resonant Feature ◽  
Difference Time ◽  
Multi Band

Based on the impedance matching and electromagnetic resonant characteristic of composite materials, we present a single-layer metamaterial absorber consisting of arch copper loop and substrate FR-4, of which the resonant frequency depended on the loop’s geometry perimeter. By combining resonant loops with different dimensions together, we can achieve multi-band absorption. The standard finite difference time domain method was used to calculate the magnitudes of reflectance, and then the induced surface current and power loss distributions were demonstrated to analyze the insight physical picture of the multi-band resonant feature. By optimizing the simulation results, the absorptivities of two absorption peaks are all above 98% when the number of copper loops is two, 95% for three absorption peaks of three loops, and 87% for four absorption peaks of four loops.

Numerical study on the short-circuit current in single layer organic solar cells with Schottkey contacts

2010 ◽  
Vol 6 (2) ◽  
pp. 103-107
Author(s):  
Chao-zhu Ma ◽  
Wei-min Meng ◽  
Ying-quan Peng ◽  
Run-sheng Wang ◽  
Rong-hua Li ◽  
...  
Keyword(s):  
Solar Cells ◽  
Organic Solar Cells ◽  
Numerical Study ◽  
Short Circuit ◽  
Single Layer ◽  
Short Circuit Current

scholarly journals Experimental and numerical study of wall layer development in a tribocharged fluidized bed

2018 ◽  
Vol 849 ◽  
pp. 860-884 ◽  
Author(s):  
Petteri Sippola ◽  
Jari Kolehmainen ◽  
Ali Ozel ◽  
Xiaoyu Liu ◽  
Pentti Saarenrinne ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Fluidized Bed ◽  
Numerical Study ◽  
Single Layer ◽  
Wall Layer ◽  
Small Scale ◽  
Average Charge ◽  
Particle Layer ◽  
Column Wall ◽  
Triboelectric Charging

The effects of triboelectricity in a small-scale fluidized bed of polyethylene particles were investigated by imaging the particle layer in the vicinity of the column wall and by measuring the pressure drop across the bed. The average charge on the particles was altered by changing the relative humidity of the gas. A triboelectric charging model coupled with a computational fluid dynamics–discrete element method (CFD-DEM) model was utilized to simulate gas–particle flow in the bed. The electrostatic forces were evaluated based on a particle–particle particle–mesh method, accounting for the surface charge on the insulating walls. It was found that simulations with fixed and uniform charge distribution among the particles capture remarkably well both the agglomeration of the particles on the wall and the associated decrease in the pressure drop across the bed. With a dynamic tribocharging model, the charging rate had to be accelerated to render the computations affordable. Such simulations with an artificial acceleration significantly over-predict charge segregation and the wall becomes rapidly sheeted with a single layer of strongly charged particles.

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