Cutting resistance of flexible armour using multiple layers of triaxial kevlar fabric

2020 ◽  
pp. 152808372096827
Author(s):  
Magdi El Messiry ◽  
Shaimaa Youssef El-Tarfawy
Keyword(s):  
Cutting Force ◽  
Areal Density ◽  
Resistance Force ◽  
Knitted Fabric ◽  
Cutting Resistance ◽  
First Case ◽  
Weft Knitted Fabric ◽  
Cut Resistance ◽  
The Relationship ◽  
Resistance Value

The textiles capable of cutting resistance found applications in the industrial and military areas to construct flexible lightweight soft body armors. In the present work, a theoretical model to understand the mechanism of fabric cut resistance in a different direction for weft-knitted, triaxial, and multiple layers structures. An experimental study of cutting resistance force was done on weft-knitted fabric with Kevlar 29 triaxial fabrics in multiple layers structure to support derived mathematical model for the effect of multiple layers structure on their cutting force. The study examines specific cut resistance of the structure from four layers of Kevlar triaxial fabrics covered with knitted fabric on both sides. The angle of cutting force varied from 0°, 60°, and 90° with respect to the yarn inclination. Results show that the cutting force of the multilayer structure is linearly proportional to the number of Kevlar triaxial fabrics layers. The specific cut resistance value of the structure from four layers of Kevlar triaxial fabrics, covered with knitted fabric on both sides, reached 544, 435, and 326 (N/g/cm2) for cutting directions: angled 60°, vertical, and horizontal, respectively. In this work, the comparison between the triaxial fabric of high areal density and multiple layers of triaxial fabric with resultant same areal density indicates that a better specific cutting force was achieved in the first case. Furthermore, it investigated the relationship between triaxial surface density, the direction of cutting, and the number of triaxial fabric layers and discussed the optimum specific properties of the different structures.

New-Technique Drilling with Modulated Rotation Spindle Machine

2013 ◽  
Vol 816-817 ◽  
pp. 206-210 ◽  
Author(s):  
Takashi Inoue ◽  
Masahiro Hagino ◽  
Yuuki Kurita ◽  
Kimitoshi Watanabe ◽  
Kazuya Ueda ◽  
...  
Keyword(s):  
Cutting Force ◽  
Small Diameter ◽  
Resistance Force ◽  
Ti Alloy ◽  
Cutting Mechanism ◽  
Basic Principles ◽  
Cutting Resistance ◽  
Acceleration And Deceleration ◽  
Chip Discharge ◽  
The Relationship

In drilling deep holes with small-diameter tools in particular, chip shape is a major problem along with tool rigidity. In this study, we developed a spindle machine that has regularly repeating acceleration and deceleration regions in each drill rotation (called modulated rotation) as a new drilling spidle machine that can improve chip discharge ability. For an analysis of the cutting mechanism based on the basic principles of this device and its drilling characteristics, holes were drilled in CFRP, and Ti alloy (Ti-6A1-4V) materials using a straight shank drill. The relationship between the torque and thrust of cutting resistance force was obtained to show the relationship between cutting chips shape and cutting force. The characteristics of drilling with the developed spindle device were evaluated in comparison with regular drilling methods. It was found that the torque with this device was reduced by about 10% compared with general drilling. Outstanding chip breakup was seen with Titanium alloys in particular, as a result of which chip discharge could be improved.

scholarly journals Estimation of resistance force at steady-state sinkage for cylindrical wheel-typed lunar/planetary exploration rovers with function of push–pull locomotion

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Daisuke Fujiwara ◽  
Naoki Tsujikawa ◽  
Tetsuya Oshima ◽  
Kojiro Iizuka
Keyword(s):  
Steady State ◽  
Estimation Method ◽  
Planetary Exploration ◽  
Experimental Result ◽  
Resistance Force ◽  
Estimation Model ◽  
Loose Soil ◽  
Key Factor ◽  
The Relationship ◽  
Resistance Forces

Abstract Planetary exploration rovers have required a high traveling performance to overcome obstacles such as loose soil and rocks. Push-pull locomotion rovers is a unique scheme, like an inchworm, and it has high traveling performance on loose soil. Push-pull locomotion uses the resistance force by keeping a locked-wheel related to the ground, whereas the conventional rotational traveling uses the shear force from loose soil. The locked-wheel is a key factor for traveling in the push-pull scheme. Understanding the sinking behavior and its resistance force is useful information for estimating the rover’s performance. Previous studies have reported the soil motion under the locked-wheel, the traction, and the traveling behavior of the rover. These studies were, however, limited to the investigation of the resistance force and amount of sinkage for the particular condition depending on the rover. Additionally, the locked-wheel sinks into the soil until it obtains the required force for supporting the other wheels’ motion. How the amount of sinkage and resistance forces are generated at different wheel sizes and mass of an individual wheel has remained unclear, and its estimation method hasn’t existed. This study, therefore, addresses the relationship between the sinkage and its resistance force, and we analyze and consider this relationship via the towing experiment and theoretical consideration. The results revealed that the sinkage reached a steady-state value and depended on the contact area and mass of each wheel, and the maximum resistance force also depends on this sinkage. Additionally, the estimation model did not capture the same trend as the experimental results when the wheel width changed, whereas, the model captured a relatively the same trend as the experimental result when the wheel mass and diameter changed.

Influence of an antimicrobial treatment on the strength properties of polyamide/elastane weft-knitted fabric

2006 ◽  
Vol 103 (6) ◽  
pp. 4012-4019 ◽  
Author(s):  
Tatjana Mihailovic ◽  
Koviljka Asanovic ◽  
Ljiljana Simovic ◽  
Petar Skundric
Keyword(s):  
Strength Properties ◽  
Antimicrobial Treatment ◽  
Knitted Fabric ◽  
Weft Knitted Fabric

Study on the Relationship between UV Protectionand Knitted Fabric Structure

2013 ◽  
Vol 59 (4) ◽  
pp. 71-74 ◽  
Author(s):  
Hang-kei Stephen CHONG ◽  
Chi-wai KAN ◽  
Jimmy Kwok-cheong LAM ◽  
Sun-pui NG ◽  
Hong HU ◽  
...  
Keyword(s):  
Knitted Fabric ◽  
Fabric Structure ◽  
The Relationship

Respiratory mechanics in mechanically ventilated patients with respiratory failure

1985 ◽  
Vol 58 (6) ◽  
pp. 1849-1858 ◽  
Author(s):  
A. Rossi ◽  
S. B. Gottfried ◽  
B. D. Higgs ◽  
L. Zocchi ◽  
A. Grassino ◽  
...  
Keyword(s):  
Time Constant ◽  
Inflation Rate ◽  
Respiratory Mechanics ◽  
Mechanically Ventilated ◽  
Mechanically Ventilated Patients ◽  
Airway Occlusion ◽  
The Relationship ◽  
Resistance Value ◽  
Ventilated Patients

In 11 mechanically ventilated patients, respiratory mechanics were measured 1) during constant flow inflation and 2) following end-inflation airway occlusion, as proposed in model analysis (J. Appl. Physiol. 58: 1840–1848, 1985. During the latter part of inflation, the relationship between driving pressure and lung volume change was linear, allowing determination of static respiratory elastance (Ers) and resistance (RT). The latter represents in each patient the maximum resistance value that can obtain with the prevailing time constant inhomogeneity. Following occlusion, Ers and RT were also obtained along with RT (min) which represents a minimum, i.e., resistance value that would obtain in the absence of time constant inhomogeneity. A discrepancy between inflation and occlusion Ers and RT was found only in the three patients without positive end-expiratory pressure, and could be attributed to recruitment of lung units during inflation. In all instances Ers and RT were higher than normal. RT(min) was lower in all patients than the corresponding values of RT, indicating that resistance was frequency dependent due to time constant inequalities. Changes in inflation rate did not affect Ers, while RT increased with increasing flow.

scholarly journals Leadership and identities in the churches in the early second century: an interpretation of Acts 16

2020 ◽  
pp. 41-67
Author(s):  
Mariano Splendido ◽  
◽  
Keyword(s):  
Group Identity ◽  
Community Leadership ◽  
Second Century ◽  
First Case ◽  
The Relationship

The aim of this work is to analyze Acts 16 as a story organized by the author based on the tensions of the ἐκκλησίαι of the beginning of the IInd century. We will identify in the narrative how are represented the concerns about community leadership and the forging of a group identity. In the first case, Paul’s interaction with the Philippians οἶκοι leads to a reflection on the relationship between ministers and faithful. In the second, the different designations that Paul receives in the chapter would demonstrate not only the complex identity of the believers, but the community proposal of the author.

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