Fabrication technique using a core and cavity mold of a hybrid composite ballistic helmet

2021 ◽  
Vol 21 (3) ◽  
pp. 623-629
Author(s):  
M.S.A.M. Alim ◽  
F. Mustapha ◽  
M.N. Abdullah ◽  
M.T.H. Sultan ◽  
M.K.H. Muda
Keyword(s):  
Room Temperature ◽  
Impact Resistance ◽  
Weight Ratio ◽  
High Strength ◽  
Fabrication Process ◽  
Mold Design ◽  
Molding Process ◽  
Thermoset Resin ◽  
Shaping Process ◽  
Curing Methods

Material used for helmet technology has transformed moderately little since the introduction of aramids, which ballistic helmets still uses woven aramids with a thermoset resin system. Most widely used strengthening material for ballistic helmet is Kevlar fibers which comprise outstanding impact resistance and high strength to weight ratio. For Kevlar reinforcement and resin shaping process, composite materials uses molding process in the fabrication methods. The most vital fabrication method is the hand lay-up process. Hand lay-up process normally consists of laying a dry fabric layer by hand onto a mold to shape into desirable design and shape. After the lay-up process is done, resin is then applied to the dry plies. There are several accessible curing methods and the most commonly used method is to let the product to cure at room temperature. This paper presents the fabrication process of ballistic helmet using a hand lay-up fabrication process with a core and cavity mold. This paper also describes the helmet mold design, materials and processing methods.

Analysis of Additive Alignment in a 90∘ Elbow Channel

2020 ◽  
Vol 28 (04) ◽  
pp. 2050032
Author(s):  
Hoang Minh Khoa Nguyen ◽  
Dong-Wook Oh
Keyword(s):  
Flow Visualization ◽  
Fiber Type ◽  
Weight Ratio ◽  
High Strength ◽  
Short Fiber ◽  
Industrial Applications ◽  
Injection Molding Process ◽  
Molding Process ◽  
Corner Region ◽  
Liquid Polymer

Short-fiber reinforced polymer composites have been widely used in industrial applications due to high strength-to-weight ratio, versatile manufacturing process, and etc. The alignment of fiber type additives plays an important role in the mechanical properties of a composite material. In this paper, an injection molding process was imitated with a liquid polymer composite flow inside a [Formula: see text] elbow channel. We performed a flow visualization experiment and analyzed the additive alignment of carbon fiber flowing in the polydimethylsiloxane (PDMS) medium. By analyzing the flow visualization images, the angle changes at the corner region of the elbow channel were calculated. At the corner region, the change of passage direction leads to the change of fiber orientation. It was observed that near to the convex region, fibers have angle change values larger than the fibers traveling near to the concave region.

Fabrication Process for a High Strength 9Cr-2W Steel Sheet

2010 ◽  
Vol 638-642 ◽  
pp. 2263-2267
Author(s):  
Tae Kyu Kim ◽  
Chang Hee Han ◽  
Sung Ho Kim ◽  
Chan Bock Lee
Keyword(s):  
Heat Treatment ◽  
Cold Rolling ◽  
Process Parameters ◽  
Carbon Concentration ◽  
Room Temperature ◽  
Steel Sheet ◽  
High Strength ◽  
Tensile Tests ◽  
Fabrication Process ◽  
Martensitic Steels

This study deals with the fabrication of high strength ferritic/martensitic steels by a control of both the carbon concentration and the fabrication process parameters. The 9Cr-2W steels containing a carbon concentration of 0.05, 0.07 and 0.11 wt% were normalized at 1050oC for 1 h, followed by a tempering at 550 and 750oC for 2 h, respectively. The results of the tensile tests at room temperature indicated that the tensile strengths were increased with an increase of the carbon concentration from 0.05 wt% to 0.07 wt%, but no more increase was observed when the carbon concentration was increased further up to 0.11%. After a cold rolling from a 4 mm to a 1 mm thickness without/with an intermediate heat treatment and a final heat treatment, the results of the tensile tests exhibited that superior tensile properties were obtained when the fabrication processes were composed of a tempering at 550oC, and a cold rolling with several intermediate heat treatments. These results could be attributed to the finely distributed precipitates in the partially recrystallized matrix. The optimized carbon concentration and the controlled fabrication process parameters are thus suggested to fabricate a high strength 9Cr-2W steel sheet.

Tough, Ductile High-Temperature Intermetallic Compounds: Results of a Four-Year Survey.

1990 ◽  
Vol 213 ◽  
Author(s):  
R.L. Fleischer ◽  
C.L. Briant ◽  
R.D. Field
Keyword(s):  
High Temperature ◽  
Intermetallic Compounds ◽  
Room Temperature ◽  
Impact Resistance ◽  
High Strength ◽  
Aircraft Engine ◽  
High Temperature Strength ◽  
Beneficial Effects ◽  
Strength And Stiffness ◽  
Binary Compounds

ABSTRACTA four-year survey of high-temperature intermetallic compounds has been aimed at identifying potentially useful structural materials for aerospace and aircraft engine applications. Since the good properties of high strength and stiffness at high temperatures are typically negated by brittleness at ambient temperature, new materials must have roomtemperature toughness or ductility. Screening has been done of 90 binary compounds with 20 different crystal structures, and 130 ternary or higher-order alloys. Testing typically included hardness vs. temperature, elastic modulus determination, and toughness evaluation via a room-temperature chisel test. Four alloy systems, including only two types that are of the simplest structures, showed substantial room-temperature toughness: Al-Ru, Ru-Sc, Ir-Nb, and Ru-Ta. Of these the last and the first are the most promising. Special features of the Ru- Ta (L1o) alloys are their room-temperature impact resistance and high-temperature strength. AIRu (B2) alloys can be tougher than the L1o structures and most are also ductile in compression at room temperature. Alloying experiments with B, Cr, and Sc show beneficial effects on ductility, oxidation resistance, and high-temperature strength.

scholarly journals Numerical and Experimental Investigation of Formability in Incremental Sheet Forming of Particle Reinforced Metal Matrix Composite Sheets

2021 ◽  
Author(s):  
Shakir Gatea ◽  
Thana Abdel Salam Tawfiq ◽  
Hengan Ou
Keyword(s):  
Metal Matrix ◽  
Room Temperature ◽  
Single Point ◽  
Weight Ratio ◽  
High Strength ◽  
Operating Conditions ◽  
Particle Composite ◽  
Heat Treated ◽  
Wide Range ◽  
Sic Particle

Abstract Metal matrix composites (MMCs) have a high strength-to-weight ratio, high stiffness, and good damage resistance under a wide range of operating conditions, making them a viable alternative to traditional materials in a variety of technical applications. Because of their high strength, composite materials are hard to deform to a significant depth at room temperature. As a result, additional treatments are required to enhance the composite's room ductility prior to deformation. In this investigation, as-received 6092Al/SiCp composite sheets (T6-condition) are heat treated to O-condition annealing to enhance its ductility in order to assess the influence of single point incremental forming (SPIF) parameters on the formability and fracture behavior of the Al/SiC particle composite sheets at room temperature. Then the annealed sheets are heat treated to T6-condition to enhance the strength and achieve properties equivalent to as-received sheets properties. The results demonstrate that the Al/SiC particle composite sheets with T6 treatment could not be deformed to the specified depth at room temperature due to low room ductility and that further treatment, such as O-condition annealing, is required to enhance the room ductility. When annealed Al/SiCp composite sheets are heat treated to T6, the sheets exhibit properties comparable to the as-received sheets. Al/SiC particle composite sheets with low SPIF parameters may have greater formability and fracture depth with low strain hardening curve.

Investigation on Flexural and Impact Properties of Abaca and Manila Hybrid Composite

2014 ◽  
Vol 1051 ◽  
pp. 102-106
Author(s):  
B. Vijaya Ramnath ◽  
V.M. Manickavasagam ◽  
C. Elanchezhian ◽  
A. Santhosh Shankar ◽  
R. Sundarrajan ◽  
...  
Keyword(s):  
Hybrid Composite ◽  
Composite Laminate ◽  
Room Temperature ◽  
Fibre Composite ◽  
Weight Ratio ◽  
High Strength ◽  
Natural Fibre ◽  
The Past ◽  
Fibre Composites ◽  
Increased Strength

Bio-fibre composites are increasingly replacing conventional and synthetic composite materials for the past two decades. This is due to their abundant availability, high strength to weight ratio and bio-degradability. Suitable properties of natural fibres can be imparted by changing the orientation of the fibres during manufacturing process. This paper proposes a hybrid property of natural fibre composite made up of Manila and abaca fibres as reinforcing agents with epoxy resin as matrix .Hand lay-up process is used for manufacturing this composite laminate. Then the treated fibres with increased strength are used with epoxy LY556 resin with HY951 hardener under room temperature. Three different samples are prepared and their mechanical properties like impact and flexural strength are found. This hybrid composite is effectively developed for automobile and electrical applications.

Sintering metal injection molding parts of tungsten-based steel using microwave and conventional heating methods

2018 ◽  
Vol 233 (11) ◽  
pp. 2138-2146 ◽  
Author(s):  
Veeresh Nayak C ◽  
Ramesh MR ◽  
Vijay Desai ◽  
Sudip Kumar Samanta
Keyword(s):  
Injection Molding ◽  
Microwave Sintering ◽  
Weight Ratio ◽  
High Strength ◽  
Conventional Heating ◽  
Metal Injection Molding ◽  
Injection Molding Process ◽  
Molding Process ◽  
Homogeneous Microstructure ◽  
Microwave Assisted

In recent years, the near net shape metal injection molding process combines desirable features of plastic injection molding and powder metallurgy processes to gain high strength-to-weight ratio for manufacturing complex-shaped parts. The metal injection molding process consists of mixing, molding, debinding, and sintering. Microwave processing has attracted much attention in global research because of its unique features such as its ability to heat and sinter a wide variety of metals and its significant advantages in energy efficiency, processing speed, and compatibility. Also, it presents few environmental risks and can produce refined microstructures. The injected samples to be sintered are composed of fine tool steel metal powder and binders, stearic acid, paraffin wax, low-density polyethylene, and polyethylene glycol (600). In recent years, microwave-assisted post-treatment is considered a novel method for processing green parts. In this work, the green parts are subjected to high-intensity microwave fields which operate at a frequency of 2.45 GHz. Metal injection molding compacts were sintered using multi-mode microwave radiation. The sintering of a metal injection molding compact by microwaves has hardly been reported. The metal injection molding compact showed better results than those produced by sintering with conventional heating. This study evaluates the effect of conventional sintering and microwave sintering on mechanical properties. By optimizing the sintering process, increased sintered hardness, a more homogeneous microstructure, and greater shrinkage were obtained using microwave-assisted sintering.

scholarly journals Ultra-Porous Nanocellulose Foams: A Facile and Scalable Fabrication Approach

Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1142 ◽  
Author(s):  
Carlo Antonini ◽  
Tingting Wu ◽  
Tanja Zimmermann ◽  
Abderrahmane Kherbeche ◽  
Marie-Jean Thoraval ◽  
...  
Keyword(s):  
Ambient Pressure ◽  
Weight Ratio ◽  
High Strength ◽  
Mechanical Tests ◽  
Immiscible Liquid ◽  
Absorption Capacity ◽  
Fabrication Process ◽  
High Porosity ◽  
Oil Absorption ◽  
Environmental Pressures

Cellulose nanofibril foams are cellulose-based porous materials with outstanding mechanical properties, resulting from the high strength-to-weight ratio of nanofibrils. Here we report the development of an optimized fabrication process for highly porous cellulose foams, based on a well-controlled freeze-thawing-drying (FTD) process at ambient pressure. This process enables the fabrication of foams with ultra-high porosity, up to 99.4%, density of 10 mg/cm3, and liquid (such as oil) absorption capacity of 100 L/kg. The proposed approach is based on the ice-templating of nanocellulose suspension in water, followed by thawing in ethanol and drying at environmental pressures. As such, the proposed fabrication route overcomes one of the major bottle-necks of the classical freeze-drying approach, by eliminating the energy-demanding vacuum drying step required to avoid wet foam collapse upon drying. As a result, the process is simple, environmentally friendly, and easily scalable. Details of the foam development fabrication process and functionalization are thoroughly discussed, highlighting the main parameters affecting the process, e.g., the concentration of nanocellulose and additives used to control the ice nucleation. The foams are also characterized by mechanical tests and oil absorption measurements, which are used to assess the foam absorption capability as well as the foam porosity. Compound water-in-oil drop impact experiments are used to demonstrate the potential of immiscible liquid separation using cellulose foams.

Design and Fabrication of Safe, Light-Weight, Flying Robots

2015 ◽  
Author(s):  
Yash Mulgaonkar ◽  
Terry Kientz ◽  
Mickey Whitzer ◽  
Vijay Kumar
Keyword(s):  
Carbon Fiber ◽  
Testing Machine ◽  
Weight Ratio ◽  
High Strength ◽  
Plaster Mold ◽  
Molding Process ◽  
Universal Testing ◽  
Liquid Silicone Rubber ◽  
Liquid Silicone ◽  
Flying Robots

This work presents the design, fabrication, and testing of a novel lightweight yet sturdy cage for micro aerial vehicles. Fabricated from a polymer infused 12k carbon-fiber using a smart liquid silicone rubber (LSR) molding process, the cage weighs only 3g and is capable of sustaining impacts at speeds up to 6m/s. We also quantitatively and qualitatively characterize the rigidity and stiffness of the cage using a universal testing machine. This paper subsequently describes the fabrication methodology employed for designing the cage to achieve the high strength-weight ratio. This involves 3D printing, silicon rubber molding, plaster mold rotocasting, wet layup of carbon fiber and finally autoclaving. Finally we demonstrate a 23g autonomous, pico quadrotor capable of sustaining stable flight with collisions with the environment.

Consolidation of Ti Powder by a Compression Rotation Shearing System at Room Temperature - Effect of Pivot Rotation Speed on Consolidation

2011 ◽  
Vol 409 ◽  
pp. 3-8 ◽  
Author(s):  
Noboru Nakayama ◽  
S. Kato ◽  
Hiroyuku Takeishi ◽  
Hiroyuki Miki
Keyword(s):  
Melting Point ◽  
High Temperatures ◽  
High Speed ◽  
Room Temperature ◽  
High Vacuum ◽  
High Strength ◽  
High Melting ◽  
Metal Powders ◽  
High Melting Point ◽  
Molding Process

Ti has high strength, good corrosion resistance, is lightweight and shows good biocompatibility. It has thus been used extensively for mechanical and medical structural components. On the other hand, the disadvantages of Ti include a high melting point, ease of oxidization at high temperatures, low specific heat and low thermal conductivity. There are three specific problems associated with Ti metallurgy. The first is that powder metallurgical processing requires high temperatures and a high vacuum, the second is that samples produced by existing powder metallurgy techniques have a low density, and the third is the occurrence of burning because of a local temperature rise during the cutting process. Therefore, in the present work, a new high-speed, room-temperature molding process involving compression rotation shearing was developed. This method can be used for solidification of metal powders by enforced plastic flow and breaking of oxide films. Therefore, no external heat is required and the molding time is short. The proposed method represents an easy approach to consolidating high melting point metallic materials.

Precipitation in Al-Li-Zr alloys

1992 ◽  
Vol 50 (1) ◽  
pp. 186-187
Author(s):  
D.M. Vanderwalker
Keyword(s):  
Fracture Toughness ◽  
Precipitation Hardening ◽  
Weight Ratio ◽  
High Strength ◽  
Transmission Electron ◽  
Water Quench ◽  
Aluminum Lithium ◽  
Aluminum Lithium Alloys ◽  
Lithium Alloys ◽  
Zr Alloys

Aluminum-lithium alloys have a low density and high strength to weight ratio. They are being developed for the aerospace industry.The high strength of Al-Li can be attributed to precipitation hardening. Unfortunately when aged, Al-Li aquires a low ductility and fracture toughness. The precipitate in Al-Li is part of a sequence SSSS → Al3Li → AlLi A description of the phases may be found in reference 1 . This paper is primarily concerned with the Al3Li phase. The addition of Zr to Al-Li is being explored to find the optimum in properties. Zirconium improves fracture toughness and inhibits recrystallization. This study is a comparision between two Al-Li-Zr alloys differing in Zr concentration.Al-2.99Li-0.17Zr(alloy A) and Al-2.99Li-0.67Zr (alloy B) were solutionized for one hour at 500oc followed by a water quench. The specimens were then aged at 150°C for 16 or 40 hours. The foils were punched into 3mm discs. The specimens were electropolished with a 1/3 nitric acid 2/3 methanol solution. The transmission electron microscopy was conducted on the JEM 200CX microscope.

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