Ceramic Armour for Armoured Vehicles Against Large-Calibre Bullets

Modelling the armour-piercing bullets B-32 calibre 12.7 mm penetration into the double-layer ceramic-composite armour has been performed for the armour blocks of two designs. The first one is a layer of ceramic square tiles supported by the glass or polyamide fabric. Modelling and subsequent ballistic tests have shown that the conical Hertz crack localized in the ceramic tile is formed. The tile is destroyed from the spread of radial cracks, and the entire armour unit becomes unable to sustain the repeated hit of the bullet. In the second case, the armour block consists of the discrete epoxy-filled cylindrical ceramic elements with spherical ends. The advantage of this "discrete" armour is localization of the damage zone and thus an ability to sustain the multiple bullet hits. The ballistic tests of the compared armour units have shown that both provide effective additional protection of light-armoured vehicles against the normal impact of the calibre 12.7 mm bullet.

Download Full-text

Micro Via-Hole Punching of LTCC-PET Double Layer Sheets

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.326-328.509 ◽

2006 ◽

Vol 326-328 ◽

pp. 509-512

Author(s):

Sung Han Rhim ◽

Seung Wook Baek ◽

Soo Ik Oh

Keyword(s):

Double Layer ◽

Ceramic Composite ◽

Tape Casting ◽

Process Condition ◽

Single Layer ◽

Multilayer Structures ◽

Optimum Process ◽

Electronic Circuits ◽

Via Holes ◽

Via Hole

In low temperature co-fired ceramic (LTCC) packaging which offers a good performance to produce multilayer structures with electronic circuits and components, the via-hole fabrication of LTCC ceramic-PET double layer sheets (green sheets or green tapes) by micro-scale punching plays an important role in providing an electric path for the interconnection between layers. Although conventional punching has been used widely and many researchers have provided useful insights of the process, they are restricted to the punching of single layer material. This paper discusses the characteristic of micro via-hole punching of double layer sheets and the optimum process condition for via-holes of good quality. Workpiece (double layer sheet) used in the present investigation consists of LTCC ceramic composite material layer (ceramic layer) of 20~100*m in thickness and PET layer of 38 and 75*m in thickness by tape-casting. The diameter of via-holes ranges from 100~300*m.

Download Full-text

Failure Analysis of Impact Damaged Pressure Vessels and Pipelines

2008 7th International Pipeline Conference, Volume 3 ◽

10.1115/ipc2008-64332 ◽

2008 ◽

Author(s):

Igor Telichev

Keyword(s):

Crack Growth ◽

Hoop Stress ◽

Damage Zone ◽

Singular Integral Equations ◽

Pressure Vessels ◽

Rear Side ◽

Front Side ◽

Unstable Crack ◽

Radial Cracks ◽

The Impact

The present paper is devoted to analysis of burst conditions of the pipeline-in-service and vessel under high pressure subjected to the debris impact due to accidental explosion. The central concern of this study is to determine the border between simple perforation and catastrophic fracture of impact damaged pressurized structure. Under certain conditions vessel perforation from the front side can lead to unstable, rapid crack growth (“unzipping”). The pressure vessel of the relatively small size can be damaged from the rear side as well. As a consequence, two main classes of catastrophic failure of such structures are likely to occur: structure fracture from the front side and failure from the rear side. Damage patterns and mechanisms leading to unstable crack growth are discussed. The impact holes in a wall of pressurized structure are considered as a crack-like defect. By the model suggested, the cracked area around the penetrated hole is simulated by two radial cracks emanating from the rim of a hole. So the diameter of the model hole is equal to the diameter of the front impact hole; the length of the crack is bounded by a damage zone, which is a zone of spall cracks adjacent to the perforated hole. In a gas-filled cylinder shell the stresses in the circumferential direction are twice the longitudinal stresses. Thus, in the process of fracturing the cracks tend to run longitudinally, perpendicular to the hoop stress. By this reason the hypothetical radial cracks are normal to the hoop stress. Nonlinear fracture mechanics techniques were used to analyze and predict whether a wall perforation will lead to mere leakage of gas, or whether an unstable crack will run and destroy the pressurized structure. The problem was solved by numerical method of singular integral equations in Chebyshev’s polynomials. A developed model was successfully applied to the simulation of experimental results.

Download Full-text

Preparation of double-layer glass-ceramic/ceramic tile from bauxite tailings and red mud

Journal of the European Ceramic Society ◽

10.1016/j.jeurceramsoc.2009.01.007 ◽

2009 ◽

Vol 29 (10) ◽

pp. 1887-1894 ◽

Cited By ~ 46

Author(s):

Huizhi Yang ◽

Changping Chen ◽

Lijun Pan ◽

Hongxia Lu ◽

Hongwei Sun ◽

...

Keyword(s):

Double Layer ◽

Glass Ceramic ◽

Red Mud ◽

Ceramic Tile ◽

Bauxite Tailings

Download Full-text

Numerical modelling of normal impact on ceramic composite armours

International Journal of Impact Engineering ◽

10.1016/0734-743x(92)90281-w ◽

1992 ◽

Vol 12 (4) ◽

pp. 639-650 ◽

Cited By ~ 32

Author(s):

R. Cortés ◽

C. Navarro ◽

M.A. Martínez ◽

J. Rodríguez ◽

V. Sanchez-Galvez

Keyword(s):

Numerical Modelling ◽

Ceramic Composite ◽

Normal Impact

Download Full-text

Cracking at the fold in double layer coated paper: the influence of latex and starch composition

TAPPI Journal ◽

10.32964/tj18.2.93 ◽

2019 ◽

Vol 18 (2) ◽

pp. 93-99

Author(s):

SEYYED MOHAMMAD HASHEMI NAJAFI ◽

DOUGLAS BOUSFIELD, ◽

MEHDI TAJVIDI

Keyword(s):

Mechanical Properties ◽

Double Layer ◽

Starch Content ◽

Single Layer ◽

Double Layers ◽

Coated Paper ◽

Coated Papers ◽

Coating Layers ◽

Scanned Images ◽

Packaging Paper

Cracking at the fold of publication and packaging paper grades is a serious problem that can lead to rejection of product. Recent work has revealed some basic mechanisms and the influence of various parameters on the extent of crack area, but no studies are reported using coating layers with known mechanical properties, especially for double-coated systems. In this study, coating layers with different and known mechanical properties were used to characterize crack formation during folding. The coating formulations were applied on two different basis weight papers, and the coated papers were folded. The binder systems in these formulations were different combinations of a styrene-butadiene latex and mixtures of latex and starch for two different pigment volume concentrations (PVC). Both types of papers were coated with single and double layers. The folded area was scanned with a high-resolution scanner while the samples were kept at their folded angle. The scanned images were analyzed within a constant area. The crack areas were reported for different types of papers, binder system and PVC values. As PVC, starch content, and paper basis weight increased, the crack area increased. Double layer coated papers with high PVC and high starch content at the top layer had more cracks in comparison with a single layer coated paper, but when the PVC of the top layer was low, cracking area decreased. No measurable cracking was observed when the top layer was formulated with a 100% latex layer.

Download Full-text

A Survey on Crypto-Steganographic Schemes and A Use Case in Healthcare System

Journal of Engineering Technology and Applied Physics ◽

10.33093/jetap.2019.1.2.6 ◽

2019 ◽

Vol 1 (2) ◽

pp. 25-33

Author(s):

Mei Ling Phang ◽

Swee Huay Heng

Keyword(s):

Social Networking ◽

Information Sharing ◽

Healthcare System ◽

Double Layer ◽

21St Century ◽

Electronic Devices ◽

Third Party ◽

Use Case ◽

Comparison Analysis ◽

Information Assets

Information sharing has become prevalent due to the expansion of social networking in this 21st century. However, electronic devices are vulnerable to various kinds of attacks. Information might be disclosed, modified and accessed by an unauthorised third party which consequently leads to the breach of confidentiality, integrity and availability of the information. Therefore, it is of utmost importance to employ the technology of cryptography and steganography to protect information assets. Cryptography and steganography have weaknesses when they are working alone. Therefore, crypto-steganography, the combination of cryptography and steganography are introduced to overcome the weaknesses in order to provide a double layer of security and protection. This paper provides a general overview of steganography and cryptography as well as a comparison analysis of different crypto-steganographic schemes. A secure crypto-steganographic system for healthcare is then developed with the implementation and integration of the secure crypto-steganographic scheme proposed by Juneja and Sandhu. This healthcare system enables users to store and deliver message in a more secure way while achieving the main goals of both cryptography and steganography.

Download Full-text