scholarly journals Dynamic Impact Surface Damage Analysis of 3D Woven Para-Aramid Armour Panels Using NDI Technique

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 877
Author(s):  
Mulat Alubel Abtew ◽  
Francois Boussu ◽  
Pascal Bruniaux ◽  
Yan Hong

The effects of the yarn composition system inside 3D woven high-performance textiles are not well investigated and understood against their final ballistic impact behaviour. The current study aims to examine the ballistic impact performances of armour panels made of different 3D woven fabric variants through postmortem observations. Four high-performance five-layer 3D woven fabric variants were engineered based on their different warp yarn compositions but similar area density. A 50 × 50 cm2 armour system of each variant, which comprises eight nonbonded but aligned panels, namely, 3D-40-8/0 (or 8/0), 3D-40-8/4 (or 8/4), 3D-40-8/8 (or 8/8) and 3D-40-4/8 (or 4/8), were prepared and moulded to resemble female frontal morphology. The armour systems were then tested with nonperforation ballistic impacts according to the National Institute of Justice (NIJ) 0101.06 standard Level-IIIA. Two high-speed cameras were used to capture the event throughout the test. Nondestructive investigation (NDI) using optical microscopic and stereoscopic 3D digital images were employed for the analysis. The armour panels made of the 8/0 and 4/8 fabric variants were perforated, whereas the armour made of the 8/8 and 8/4 fabric variants showed no perforation. Besides, the armour made of the 8/4 fabric variant revealed higher local and global surface displacements than the other armours. The current research findings are useful for further engineering of 3D woven fabric for seamless women’s impact protective clothing.

2014 ◽  
Vol 553 ◽  
pp. 757-762 ◽  
Author(s):  
Cheng Yang ◽  
Phuong Tran ◽  
Tuan Ngo ◽  
Priyan Mendis ◽  
William Humphries

Woven fabrics are widely used in various protective applications. The effects of different woven architectures (such as plain, basket, twill and satin) on impact resistance performance have not been adequately studied. In this work, high-speed impact testing on single layer plain weave structures has been carried out using a gas gun experimental setup. Ballistic resistance performance of the woven fabric is evaluated based on the resultant velocity of the projectile, as well as the post-mortem failure analysis. Finite element computational models are presented in this research, thereby providing predictive capability for the manufacturer and designer in order to minimise field testing, as well as shedding light on to the damage mechanisms of composite fabrics subjected to ballistic impact. The numerical model is validated with the experimental results in terms of dissipated energy and resultant velocity. Numerical investigation is conducted on other woven structures of identical areal density for comparison, revealing the importance of fabric architecture. The influences of yarn-yarn and yarn-projectile friction properties on the ballistic performance of various textile structures are also presented.


2019 ◽  
pp. 152808371986288 ◽  
Author(s):  
Mulat Alubel Abtew ◽  
François Boussu ◽  
Pascal Bruniaux ◽  
Carmen Loghin ◽  
Irina Cristian ◽  
...  

This paper investigates the influences of woven fabric type, impact locations and number of layers on ballistic impact performances of target panels through trauma dimension and panel surface damage mechanisms for lightweight women ballistic vest design. Three panels with 30, 35 and 40 layers of two-dimensional plain weave and another two panels with 30 and 40 layers of three-dimensional warp interlock fabrics were prepared. The three-dimensional woven fabric was manufactured using automatic Dornier weaving machine, whereas the two-dimensional fabric (with similar p-aramid fibre type (Twaron®)) was received from the Teijin Company. The ballistic tests were carried out according to NIJ Standard-0101.06 Level IIIA. Based on the result, woven fabric construction type, number of layers and target locations were directed an upshot on the trauma measurement values of the tested target panels. For example, 40 layers of two-dimensional plain weave fabric panels show lower trauma measurement values as compared to its counterpart three-dimensional warp interlock fabric panels with similar layer number. Moreover, 40 layers of two-dimensional fabric panels revealed 47% and 39% trauma depth reduction as compared to panels with 30 layers of two-dimensional fabric panel in moulded (target point 1) and non-moulded (target point 6), respectively. Due to higher amount of primary yarn involvement, two-dimensional plain weave fabric panel face higher level of local surface damages but less severe and fibrillated yarns than three-dimensional warp interlock fabrics panels. Moreover, three-dimensional warp interlock fabric panels required higher number of layers compared to two-dimensional plain weave aramid fabrics to halt the projectiles. Similarly, based on the post-mortem analysis of projectile, higher projectile debris deformation was recorded for panels having higher number of layers for both types of fabrics at similar target locations.


2020 ◽  
Vol 10 (14) ◽  
pp. 4873 ◽  
Author(s):  
Mulat Alubel Abtew ◽  
Francois Boussu ◽  
Pascal Bruniaux ◽  
Carmen Loghin ◽  
Irina Cristian

This paper investigates the effects of warp yarns ratios on the ballistic performances of three-dimensional (3D) warp interlock p-aramid fabrics. Four 3D warp interlock variants with different binding and stuffer warp yarns ratios were designed and developed. Except for warp yarns ratios, similar fabric parameters and manufacturing conditions were considered. Two-dimensional (2D) woven fabric having similar material characteristics and recommended for female seamless soft body armor are also considered for comparisons. Five ballistic panels, one from 2D plain weave fabric and the rest four from the other 3D warp interlock variants were prepared in a non-angled layer alignment and non-stitched but bust-shaped molded form. The ballistic test is carried out according to NIJ (National Institute of Justice) standard-level IIIA. Back Face Signature (BFS) was then modeled and measured to compute both trauma and panels’ energy-absorbing capability. The result showed significant ballistic improvement in the 3D warp interlock variant with optimum warp yarns ratios over traditional 2D plain weave fabrics. 3D warp interlock fabric panel made with 66.6% binding and 33.3% stuffer warp yarn ratio revealed both lower BFS depth and higher energy absorbing capacity (%) than other panels made of 2D plain weave and 3D warp interlock fabric variants.


Author(s):  
N. Yoshimura ◽  
K. Shirota ◽  
T. Etoh

One of the most important requirements for a high-performance EM, especially an analytical EM using a fine beam probe, is to prevent specimen contamination by providing a clean high vacuum in the vicinity of the specimen. However, in almost all commercial EMs, the pressure in the vicinity of the specimen under observation is usually more than ten times higher than the pressure measured at the punping line. The EM column inevitably requires the use of greased Viton O-rings for fine movement, and specimens and films need to be exchanged frequently and several attachments may also be exchanged. For these reasons, a high speed pumping system, as well as a clean vacuum system, is now required. A newly developed electron microscope, the JEM-100CX features clean high vacuum in the vicinity of the specimen, realized by the use of a CASCADE type diffusion pump system which has been essentially improved over its predeces- sorD employed on the JEM-100C.


Author(s):  
Marc H. Peeters ◽  
Max T. Otten

Over the past decades, the combination of energy-dispersive analysis of X-rays and scanning electron microscopy has proved to be a powerful tool for fast and reliable elemental characterization of a large variety of specimens. The technique has evolved rapidly from a purely qualitative characterization method to a reliable quantitative way of analysis. In the last 5 years, an increasing need for automation is observed, whereby energy-dispersive analysers control the beam and stage movement of the scanning electron microscope in order to collect digital X-ray images and perform unattended point analysis over multiple locations.The Philips High-speed Analysis of X-rays system (PHAX-Scan) makes use of the high performance dual-processor structure of the EDAX PV9900 analyser and the databus structure of the Philips series 500 scanning electron microscope to provide a highly automated, user-friendly and extremely fast microanalysis system. The software that runs on the hardware described above was specifically designed to provide the ultimate attainable speed on the system.


Author(s):  
M. T. Postek ◽  
A. E. Vladar

One of the major advancements applied to scanning electron microscopy (SEM) during the past 10 years has been the development and application of digital imaging technology. Advancements in technology, notably the availability of less expensive, high-density memory chips and the development of high speed analog-to-digital converters, mass storage and high performance central processing units have fostered this revolution. Today, most modern SEM instruments have digital electronics as a standard feature. These instruments, generally have 8 bit or 256 gray levels with, at least, 512 × 512 pixel density operating at TV rate. In addition, current slow-scan commercial frame-grabber cards, directly applicable to the SEM, can have upwards of 12-14 bit lateral resolution permitting image acquisition at 4096 × 4096 resolution or greater. The two major categories of SEM systems to which digital technology have been applied are:In the analog SEM system the scan generator is normally operated in an analog manner and the image is displayed in an analog or "slow scan" mode.


Author(s):  
Sai Venkatramana Prasada G.S ◽  
G. Seshikala ◽  
S. Niranjana

Background: This paper presents the comparative study of power dissipation, delay and power delay product (PDP) of different full adders and multiplier designs. Methods: Full adder is the fundamental operation for any processors, DSP architectures and VLSI systems. Here ten different full adder structures were analyzed for their best performance using a Mentor Graphics tool with 180nm technology. Results: From the analysis result high performance full adder is extracted for further higher level designs. 8T full adder exhibits high speed, low power delay and low power delay product and hence it is considered to construct four different multiplier designs, such as Array multiplier, Baugh Wooley multiplier, Braun multiplier and Wallace Tree multiplier. These different structures of multipliers were designed using 8T full adder and simulated using Mentor Graphics tool in a constant W/L aspect ratio. Conclusion: From the analysis, it is concluded that Wallace Tree multiplier is the high speed multiplier but dissipates comparatively high power. Baugh Wooley multiplier dissipates less power but exhibits more time delay and low PDP.


Nanophotonics ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 937-945
Author(s):  
Ruihuan Zhang ◽  
Yu He ◽  
Yong Zhang ◽  
Shaohua An ◽  
Qingming Zhu ◽  
...  

AbstractUltracompact and low-power-consumption optical switches are desired for high-performance telecommunication networks and data centers. Here, we demonstrate an on-chip power-efficient 2 × 2 thermo-optic switch unit by using a suspended photonic crystal nanobeam structure. A submilliwatt switching power of 0.15 mW is obtained with a tuning efficiency of 7.71 nm/mW in a compact footprint of 60 μm × 16 μm. The bandwidth of the switch is properly designed for a four-level pulse amplitude modulation signal with a 124 Gb/s raw data rate. To the best of our knowledge, the proposed switch is the most power-efficient resonator-based thermo-optic switch unit with the highest tuning efficiency and data ever reported.


2021 ◽  
Vol 35 ◽  
pp. 102249
Author(s):  
S. Thakur ◽  
S. Maiti ◽  
K. Sardar ◽  
N. Besra ◽  
P. Bairi ◽  
...  

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