scholarly journals Numerical Study on the Effect of Z-Warps on the Ballistic Responses of Para-Aramid 3D Angle-Interlock Fabrics

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 479
Author(s):  
Yingxue Yang ◽  
Xiuqin Zhang ◽  
Xiaogang Chen ◽  
Shengnan Min
Keyword(s):  
Energy Absorption ◽  
Numerical Study ◽  
Three Dimensional ◽  
Local Stress ◽  
Woven Fabrics ◽  
Layer By Layer ◽  
Future Design ◽  
Structural Support ◽  
Fabric Structures ◽  
The Impact

In order to achieve an efficient ballistic protection at a low weight, it is necessary to deeply explore the energy absorption mechanisms of ballistic fabric structures. In this paper, finite element (FE) yarn-level models of the designed three-dimensional (3D) angle-interlock (AI) woven fabrics and the laminated two-dimensional (2D) plain fabrics are established. The ballistic impact responses of fabric panels with and without the interlocking Z-warp yarns during the projectile penetration are evaluated in terms of their energy absorption, deformation, and stress distribution. The Z-warps in the 3D fabrics bind different layers of wefts together and provide the panel with structural support along through-the-thickness direction. The results show that the specific energy absorption (SEA) of 3D fabrics is up to 88.1% higher than that of the 2D fabrics. The 3D fabrics has a wider range of in-plane stress dispersion, which demonstrates its structural advantages in dispersing impact stress and getting more secondary yarns involved in energy absorption. However, there is a serious local stress concentration in 2D plain woven fabrics near the impact location. The absence of Z-warps between the layers of 2D laminated fabrics leads to a premature layer by layer failure. The findings are indicative for the future design of ballistic amors.

scholarly journals A guideline for 3D printing terminology in biomedical research utilizing ISO/ASTM standards

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Amy E. Alexander ◽  
Nicole Wake ◽  
Leonid Chepelev ◽  
Philipp Brantner ◽  
Justin Ryan ◽  
...  
Keyword(s):  
3D Printing ◽  
Medical Literature ◽  
Three Dimensional ◽  
Physical Object ◽  
Medical Community ◽  
Layer By Layer ◽  
Digital File ◽  
Standardized Terminology ◽  
Standard Terms ◽  
The Impact

AbstractFirst patented in 1986, three-dimensional (3D) printing, also known as additive manufacturing or rapid prototyping, now encompasses a variety of distinct technology types where material is deposited, joined, or solidified layer by layer to create a physical object from a digital file. As 3D printing technologies continue to evolve, and as more manuscripts describing these technologies are published in the medical literature, it is imperative that standardized terminology for 3D printing is utilized. The purpose of this manuscript is to provide recommendations for standardized lexicons for 3D printing technologies described in the medical literature. For all 3D printing methods, standard general ISO/ASTM terms for 3D printing should be utilized. Additional, non-standard terms should be included to facilitate communication and reproducibility when the ISO/ASTM terms are insufficient in describing expository details. By aligning to these guidelines, the use of uniform terms for 3D printing and the associated technologies will lead to improved clarity and reproducibility of published work which will ultimately increase the impact of publications, facilitate quality improvement, and promote the dissemination and adoption of 3D printing in the medical community.

scholarly journals Drops bouncing off macro-textured superhydrophobic surfaces

2017 ◽  
Vol 824 ◽  
pp. 866-885 ◽  
Author(s):  
Ali Mazloomi Moqaddam ◽  
Shyam S. Chikatamarla ◽  
Iliya V. Karlin
Keyword(s):  
Contact Time ◽  
Numerical Study ◽  
Three Dimensional ◽  
Superhydrophobic Surfaces ◽  
Nonlinear Behaviour ◽  
Textured Surfaces ◽  
Texture Density ◽  
Wide Range ◽  
Quantitative Manner ◽  
The Impact

Recent experiments with droplets impacting macro-textured superhydrophobic surfaces revealed new regimes of bouncing with a remarkable reduction of the contact time. Here we present a comprehensive numerical study that reveals the physics behind these new bouncing regimes and quantifies the roles played by various external and internal forces. For the first time, accurate three-dimensional simulations involving realistic macro-textured surfaces are performed. After demonstrating that simulations reproduce experiments in a quantitative manner, the study is focused on analysing the flow situations beyond current experiments. We show that the experimentally observed reduction of contact time extends to higher Weber numbers, and analyse the role played by the texture density. Moreover, we report a nonlinear behaviour of the contact time with the increase of the Weber number for imperfectly coated textures, and study the impact on tilted surfaces in a wide range of Weber numbers. Finally, we present novel energy analysis techniques that elaborate and quantify the interplay between the kinetic and surface energy, and the role played by the dissipation for various Weber numbers.

Numerical study of asymmetric and axisymmetric thermal jet with entropy generation concept

2021 ◽  
Vol 15 (1) ◽  
pp. 7628-7636
Author(s):  
D. Belakhal ◽  
Kouider Rahmani ◽  
Amel Elkaroui Elkaroui ◽  
Syrine Ben Haj Ayech ◽  
Nejla Mahjoub Saïd ◽  
...  
Keyword(s):  
Entropy Generation ◽  
Numerical Study ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Variable Density ◽  
Current Investigation ◽  
Numerical Resolution ◽  
Different Temperatures ◽  
Density Ratios ◽  
The Impact

In the current investigation, numerical study of a thermal jet of asymmetric (rectangular and elliptical) and axisymmetric (circular) geometry was investigated with variable density to verify the impact of the ratio of density and geometry on the generation of entropy. The central jet was brought to different temperatures (194, 293 and 2110 K) to obtain density ratios (0.66, 1 and 7.2) identical to a mixture jet ((Air-CO2), (Air-Air) and (Air-He)), respectively. Solving the three-dimensional numerical resolution of the Navier Stocks for turbulent flow permanent enclosed on the turbulence model K-εstandard was made. The results acquired are compared with that carried out in previous experimental studies, where it was concluded that, the axisymmetric (circular) geometry increases the entropy generation.

Numerical study of the impact of water injection holes arrangement on cavitation flow control

2019 ◽  
Vol 103 (1) ◽  
pp. 003685041987774 ◽  
Author(s):  
Wei Wang ◽  
Qingdian Zhang ◽  
Tao Tang ◽  
Shengpeng Lu ◽  
Qi Yi ◽  
...  
Keyword(s):  
Flow Field ◽  
Numerical Study ◽  
Water Injection ◽  
Three Dimensional ◽  
Hydrodynamic Performance ◽  
Cavitation Flow ◽  
Suction Surface ◽  
Double Row ◽  
Suppression Effect ◽  
The Impact

A method of water injection to flow field using distributed holes on the suction surface of hydrofoil is presented in this article to control cavitation flow. Modified renormalization group k–ε turbulence model is coupled with full-cavitation model to calculate periodical cavitation patterns and the dynamic characteristics of the NACA66(MOD) hydrofoil. Water injection is found to be highly effective for cavitation suppression. The cavitation suppression effect of distributed regulation of jet holes and porosities along three-dimensional spanwise hydrofoil is also investigated. The appropriate porosities of single row spanwise jet holes and optimal jet position of double row jet holes are revealed for both cavitation suppression and good hydrodynamic performance. Double row jet holes setting in forward trapezoidal arrangement shows great potential for cavitation suppression and hydrodynamic performance. This research provides a method of water injection to flow field to actively control cavitation, which will facilitate development of engineering designs.

Interplay of fabric structure and shear thickening fluid impregnation in moderating the impact response of high-performance woven fabrics

2020 ◽  
Vol 54 (28) ◽  
pp. 4387-4395
Author(s):  
Sanchi Arora ◽  
Abhijit Majumdar ◽  
Bhupendra Singh Butola
Keyword(s):  
Beneficial Effect ◽  
Energy Absorption ◽  
Impact Energy ◽  
High Performance ◽  
Research Work ◽  
Impact Resistance ◽  
Woven Fabrics ◽  
Woven Fabric ◽  
Fabric Structure ◽  
The Impact

The beneficial effect of STF impregnation in enhancing the impact resistance of high-performance fabrics has been extensively reported in the literature. However, this research work reports that fabric structure has a decisive role in moderating the effectiveness of STF impregnation in terms of impact energy absorption. Plain woven fabrics having sett varying from 25 × 25 inch−1 to 55 × 55 inch−1 were impregnated with STF at two different padding pressures to obtain different add-ons. The impact energy absorption by STF impregnated loosely woven fabrics was found to be higher than that of their neat counterparts for both levels of add-on, while opposite trend was observed in case of tightly woven fabrics. Further, comparison of tightly woven plain, 2/2 twill, 3/1 twill and 2 × 2 matt fabrics revealed beneficial effect of STF impregnation, except for the plain woven fabric, establishing that there exists a fabric structure-STF impregnation interplay that tunes the impact resistance of woven fabrics.

Numerical Study on Impact Response of Aircraft Sandwich Wing Made of Fiber-Metal Laminate Face-Sheets Subjected to Bird Strike

2012 ◽  
Vol 488-489 ◽  
pp. 8-13 ◽  
Author(s):  
S.M.R. Khalili ◽  
M. Assar ◽  
R. Eslami Farsani ◽  
I. Hajiyousefi
Keyword(s):  
Energy Absorption ◽  
Numerical Study ◽  
Metal Layer ◽  
Element Model ◽  
Fiber Types ◽  
Bird Strike ◽  
Impact Phenomena ◽  
Impact Responses ◽  
Fiber Metal ◽  
The Impact

Aircraft structures are frequently subjected to impacts from objects such as runway debris and birds. In new aircraft structural design, Fiber Metal Laminates (FMLs) play a significant role due to their excellent mechanical properties, particularly the impact properties. In this study, the aircraft sandwich wing with FML face-sheets are analyzed by finite element model for simulating the bird strike. The numerical simulations of bird strike impact are performed adopting a lagrangian approach to design the wing by MSC/PATRAN FE code. The numerical obtained results are compared with the results in the literature for validation of the model. The effect of fiber orientations, fiber types, metal types in FML face sheets in sandwich wing on impact responses are investigated. The impact responses are illustrated by displacement history, contact force history and energy absorption. According to these results, the sandwich panel with FML skin is suitable structure for energy absorption (that is the most important factor in impact phenomena). The lay-ups with titanium metal layer with aramid fibers are the best.

scholarly journals Numerical and Experimental Study on Deficient Short Steel Tubes Strengthened with CFRP Under Compression

2019 ◽  
Author(s):  
Mohammad Reza Ghaemdoust ◽  
Omid Yousefi ◽  
Kambiz Narmashiri ◽  
Masoumeh Karimian
Keyword(s):  
Bearing Capacity ◽  
Numerical Study ◽  
Three Dimensional ◽  
Local Buckling ◽  
Steel Tubes ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Steel Columns ◽  
Repair Costs ◽  
The Impact

In view of development and repair costs, support of structures is imperative. Several factors, for example, design and calculation errors, absence of appropriate installation, change of structures application, exhaustion, seismic tremor, fire and natural conditions diminish their strength. In such cases, structures have need of rehabilitation and restoration to achieve their original performance. One of the most up to date materials for retrofitting is carbon fiber reinforced polymer (CFRP) that can provide an amount of restriction to postpone buckling of thin steel walls. This paper provides a numerical and experimental investigation on CFRP strengthened short steel tubes with initial horizontal and vertical deficiency under compression. Ten square and circular specimens were tested to study effects of the following parameters: (1) position of deficiency, horizontal or vertical; (2) tube shape, square or circular; (3) CFRP strengthening. In the experiments, axial static loading was gradually applied and for the numerical study three-dimensional (3D) static nonlinear analysis method using ABAQUS software was performed. The results show that deficiency reduces load-bearing capacity of steel columns and the impact of horizontal deficiency is higher than the impact of vertical deficiency, in both square and circular tubes. Use of CFRP materials for strengthening of short steel columns with initial deficiency indicates that fibers play a considerable role on increasing load bearing capacity, reducing stress at the damage location, preventing deformation caused by deficiency and delaying local buckling. Both numerical and experimental outcomes are in good agreement, which underlines the accuracy of the models adopted.

Numerical Investigation of the Impact of Part-Span Connectors on Aero-Thermodynamics in a Low Pressure Industrial Steam Turbine

2014 ◽  
Author(s):  
M. Häfele ◽  
J. Starzmann ◽  
M. Grübel ◽  
M. Schatz ◽  
D. M. Vogt ◽  
...  
Keyword(s):  
Steam Turbine ◽  
Numerical Study ◽  
Three Dimensional ◽  
Measurement Data ◽  
Cross Flow ◽  
Low Pressure ◽  
Wet Steam ◽  
Flow Vortex ◽  
The Impact ◽  
Non Equilibrium

A numerical study on the flow in a three stage low pressure industrial steam turbine with conical friction bolts in the last stage and lacing wires in the penultimate stage is presented and analyzed. Structured high-resolution hexahedral meshes are used for all three stages and the meshing methodology is shown for the rotor with friction bolts and blade reinforcements. Modern three-dimensional CFD with a non-equilibrium wet steam model is used to examine the aero-thermodynamic effects of the part-span connectors. A performance assessment of the coupled blades at part load, design and overload condition is presented and compared with measurement data from an industrial steam turbine test rig. Detailed flow field analyses and a comparison of blade loading between configurations with and without part-span connectors are presented in this paper. The results show significant interaction of the cross flow vortex along the part-span connector with the blade passage flow causing aerodynamic losses. This is the first time that part-span connectors are being analyzed using a non-equilibrium wet steam model. It is shown that additional wetness losses are induced by these elements.

Numerical Study on the Anti-Ballistic Properties of Metal Encapsulating Ceramic Composite Armors

2015 ◽  
Vol 723 ◽  
pp. 26-30 ◽  
Author(s):  
Jiang Ren Lu ◽  
Xin Li Sun ◽  
Xing Hui Cai ◽  
San Qiang Dong ◽  
Guo Liang Wang
Keyword(s):  
Ceramic Composite ◽  
Numerical Study ◽  
Three Dimensional ◽  
Ceramic Block ◽  
Ballistic Resistance ◽  
Limit Velocity ◽  
Ballistic Properties ◽  
Ballistic Limit Velocity ◽  
The Impact ◽  
Two Hybrid

The impact responses and ballistic resistance of the metal encapsulating ceramic composite armors with same area density and two hybrid cores are investigated. The hybrid cores include square metallic lattice with ceramic block insertions, and square metallic lattice with ceramic ball insertions and void-filling epoxy resin. Three-dimensional (3D) finite element (FE) simulations are carried out for each composite armors impacted by bullet with 12.7mm diameter. The focus is placed on the energy absorption capabilities and ballistic limit velocity of different composite armors. Results indicate that two kind of armors can improve the ballistic resistance properties and save mass of 22% and 25% compared to the homogeneous 4340 steel, respectively.

On the Role of Leading-Edge Bumps in the Control of Stall Onset in Axial Fan Blades

2013 ◽  
Vol 135 (8) ◽  
Author(s):  
Alessandro Corsini ◽  
Giovanni Delibra ◽  
Anthony G. Sheard
Keyword(s):  
Numerical Study ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Leading Edge ◽  
Suction Side ◽  
Axial Fan ◽  
Early Recovery ◽  
Viscosity Models ◽  
Flow Mechanisms ◽  
The Impact

Taking a lead from the humpback whale flukes, characterized by a series of bumps that result in a sinusoidal-like leading edge, this paper reports on a three-dimensional numerical study of sinusoidal leading edges on cambered airfoil profiles. The turbulent flow around the cambered airfoil with the sinusoidal leading edge was computed at different angles of attack with the open source solver OpenFOAM, using two different eddy viscosity models integrated to the wall. The reported research focused on the effects of the modified leading edge in terms of lift-to-drag performance and the influence of camber on such parameters. For these reasons a comparison with a symmetric airfoil is provided. The research was primarily concerned with the elucidation of the fluid flow mechanisms induced by the bumps and the impact of those mechanisms on airfoil performance, on both symmetric and cambered profiles. The bumps on the leading edge influenced the aerodynamic performance of the airfoil, and the lift curves were found to feature an early recovery in post-stall for the symmetric profile with an additional gain in lift for the cambered profile. The bumps drove the fluid dynamic on the suction side of the airfoil, which in turn resulted in the capability to control the separation at the trailing edge in coincidence with the peak of the sinusoid at the leading edge.

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