Dynamic Analysis of Sandwiched Composite Foldable Structure under Heavy Vehicle Load

2011 ◽  
Vol 110-116 ◽  
pp. 2331-2336
Author(s):  
Norazman Mohamad Nor ◽  
S.T. Agusril ◽  
Mohamed Yusof Alias ◽  
A.M.A. Zaidi ◽  
Abdullah Shohaimi
Keyword(s):  
Weight Ratio ◽  
High Strength ◽  
Structural Element ◽  
Dynamic Simulations ◽  
Primary Material ◽  
Long Span ◽  
Disaster Relief Operations ◽  
Rapid Construction ◽  
Relief Operations ◽  
Strength And Stiffness

Foldable structures are very important for the purpose of rapid construction and bridging system. Such structural element can be utilized in disaster relief operations. In the early days, portable structure such as military bridges were made from steel, causing the weight of the structure to be huge, subsequently it will be costly to operate. To overcome these problems, aluminium and metal alloy were introduced to reduce the weight of such structure. Use of composite material such as Carbon Fiber Reinforced Polymer (CFRP) emerges as a lighter alternative being considered to be the primary material for the portable structure. The use of the CFRP as a primary material is due to its high strength to weight ratio, thus make it lighter than steel and other alloy. In this research, a long-span portable structure is analysed and designed using finite element method. Several dynamic simulations are made to test various possible lay-up including use of core in order to increase strength and stiffness of the member. From the trials it can be concluded that with proper design and fabrication, CFRP is capable of carrying the designed dynamic load. Furthermore, use of core layers for top flange can improve the performance of the structure significantly, while use of core to the webs stiffen the webs against buckling and further improve the overall performance of the structure.

scholarly journals Ultrahigh Ballistic Resistance of Twisted Bilayer Graphene

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 206
Author(s):  
Qing Peng ◽  
Sheng Peng ◽  
Qiang Cao
Keyword(s):  
Weight Ratio ◽  
High Strength ◽  
Bilayer Graphene ◽  
Energy Propagation ◽  
Dynamic Simulations ◽  
Protective Material ◽  
Impact Performance ◽  
Ballistic Resistance ◽  
Twisted Bilayer Graphene ◽  
The Impact

Graphene is a good candidate for protective material owing to its extremely high stiffness and high strength-to-weight ratio. However, the impact performance of twisted bilayer graphene is still obscure. Herein we have investigated the ballistic resistance capacity of twisted bilayer graphene compared to that of AA-stacked bilayer graphene using molecular dynamic simulations. The energy propagation processes are identical, while the ballistic resistance capacity of the twisted bilayer graphene is almost two times larger than the AA-bilayer graphene. The enhanced capacity of the twisted bilayer graphene is assumed to be caused by the mismatch between the two sheets of graphene, which results in earlier fracture of the first graphene layer and reduces the possibility of penetration.

Harvesting New York City - Old-Growth Urban Forestry

2019 ◽  
Author(s):  
Dan Bergsagel ◽  
Timothy D. Lynch
Keyword(s):  
New York ◽  
Research Work ◽  
Urban Forestry ◽  
Weight Ratio ◽  
High Strength ◽  
Structural Element ◽  
Building Stock ◽  
Old Growth ◽  
Building Type ◽  
The City

<p>New York is known as a metropolis of skyscrapers; however less than 1.5% of the 1 million buildings in the city stand over seven stories tall. Over 95% are thought to be of wood-frame or masonry and wood construction.</p><p>Most of this building stock was constructed using wood sourced from old-growth forests across the eastern seaboard. The city now sits on a stockpile of wood which germinated before New Amsterdam became New York, and which was felled while signatories of the Declaration of Independence were still President; this is structurally valuable hard, dense and high strength-to-weight ratio wood. As our buildings degrade and require renovation or replacement the city must ensure that this resource is not wasted, for environmental and economic reasons.</p><p>The total number of buildings is large, but because of the rapid and repetitive way that NYC was constructed the variation in building type and structural element sizes across the building population is small. Cross referencing NYC department databases using geographic information systems allowed the Department of Buildings to produce an estimate of the number of buildings in the city of each type. Assessment of historic pattern books, prescriptive regulations, and inspection of existing buildings allows generic estimates of wood dimension and quantity per building type. Combined, this data allows the estimation of the annual rate of release of wood from demolition in NYC - a predicted supply available for future use. A review of existing practices in wood salvage, processing and reuse is then assessed in context, outlining proposals for future local policy and research work.</p>

scholarly journals Mechanical Properties of Fibre Reinforced Polymers under Elevated Temperatures: An Overview

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2600
Author(s):  
Milad Bazli ◽  
Milad Abolfazli
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperatures ◽  
Mechanical Performance ◽  
Weight Ratio ◽  
High Strength ◽  
Civil Infrastructures ◽  
Frp Composites ◽  
Frp Composite ◽  
Materials Used ◽  
Strength And Stiffness

Fibre-reinforced polymer (FRP) composite is one of the most applicable materials used in civil infrastructures, as it has been proven advantageous in terms of high strength and stiffness to weight ratio and anti-corrosion. The performance of FRP under elevated temperatures has gained significant attention among academia and industry. A comprehensive review on experimental and numerical studies investigating the mechanical performance of FRP composites subjected to elevated temperatures, ranging from ambient to fire condition, is presented in this paper. Over 100 research papers on the mechanical properties of FRP materials including tensile, compressive, flexural and shear strengths and moduli are reviewed. Although they report dispersed data, several interesting conclusions can be drawn from these studies. In general, exposure to elevated temperatures near and above the resin glass transition temperature, Tg, has detrimental effects on the mechanical characteristics of FRP materials. On the other hand, elevated temperatures below Tg can cause low levels of degradation. Discussions are made on degradation mechanisms of different FRP members. This review outlines recommendations for future works. The behaviour of FRP composites under elevated temperatures provides a comprehensive understanding based on the database presented. In addition, a foundation for determining predictive models for FRP materials exposed to elevated temperatures could be laid using the finding that this review presents.

scholarly journals Design, Manufacturing and Analysis of Composite Leaf Spring

2021 ◽  
Vol 9 (VI) ◽  
pp. 2656-2665
Author(s):  
Vaishnavi S. Thorat
Keyword(s):  
Automobile Industry ◽  
Weight Reduction ◽  
Weight Ratio ◽  
High Strength ◽  
Material Design ◽  
Leaf Spring ◽  
Glass Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Glass Fibre Reinforced ◽  
Strength And Stiffness

Now-a-days it is necessary to conserve natural resources, economize energy and weight reduction. Weight reduction of vehicle has become the main issue in Automobile Industries. It can be achieved by introduction of better material, design optimization and better manufacturing process. The Automobile Industry has interest for replacement of Steel Leaf Spring with Composite Leaf Spring. Composite Material has High Strength and Stiffness to Weight Ratio. The Objective is to compare the Stresses, Deformation, Elastic Strain and Weight of Composite Leaf Spring with that of Steel Leaf Spring. The Material Selected is Glass Fibre Reinforced Polymer is used against Conventional Steel. The Leaf Spring was modelled in CATIA and analysis done in ANSYS Software.

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.

TUNGUM ALLOY

Alloy Digest ◽  
2012 ◽  
Vol 61 (5) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
Weight Ratio ◽  
High Strength ◽  
Fatigue Properties ◽  
Excellent Corrosion Resistance

Abstract Tungum alloy combines an unusually high strength-to-weight ratio, with ductility, excellent corrosion resistance, and good fatigue properties. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming. Filing Code: Cu-806. Producer or source: Tungum Ltd.

SANDVIK Ti-3Al-2.5V GRADE 9

Alloy Digest ◽  
1997 ◽  
Vol 46 (9) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Endurance Limit ◽  
Weight Ratio ◽  
High Strength ◽  
Strain Ratio ◽  
Bend Strength ◽  
Aerospace Applications ◽  
Excellent Corrosion Resistance ◽  
Titanium Aluminum ◽  
Fatigue Endurance

Abstract Sandvik Ti-3Al-2.5V Grade 9 titanium-aluminum alloy offers excellent corrosion resistance, especially to chloride media, and has a high strength-to-weight ratio, which is especially suitable for use in aerospace applications. Tubing can be produced having a CSR (contractile strain ratio) that enhances the fatigue endurance limit. This datasheet provides information on composition, physical properties, elasticity, tensile properties, and bend strength as well as fatigue. It also includes information on corrosion resistance as well as forming, machining, and joining. Filing Code: TI-109. Producer or source: Sandvik.

DONEGAL DC-50

Alloy Digest ◽  
1954 ◽  
Vol 3 (8) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Physical Properties ◽  
Surface Treatment ◽  
Tensile Properties ◽  
Precipitation Hardening ◽  
Weight Ratio ◽  
High Strength ◽  
Heat Treating

Abstract Donegal DC-50 is a precipitation hardening stainless steel having high strength-weight ratio. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as casting, heat treating, machining, joining, and surface treatment. Filing Code: SS-17. Producer or source: Donegal Manufacturing Corporation.

scholarly journals Tribological characterisation of magnesium matrix nanocomposites: A review

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110090
Author(s):  
Sudip Banerjee ◽  
Prasanta Sahoo ◽  
J Paulo Davim
Keyword(s):  
Weight Ratio ◽  
High Strength ◽  
Stir Casting ◽  
Tribological Behaviour ◽  
Magnesium Matrix ◽  
Friction Stir ◽  
Wear Friction ◽  
Melt Deposition ◽  
Mechanical And Tribological Characteristics ◽  
Matrix Nanocomposites

Magnesium matrix nanocomposites (Mg-MNCs) are high grade materials widely used in aerospace, electronics, biomedical and automotive sectors for high strength to weight ratio, excellent sustainability and superior mechanical and tribological characteristics. Basic properties of Mg-MNCs rely on type and amount of reinforcement and fabrication process. Current study reviews existing literatures to explore contribution of different parameters on tribological properties of Mg-MNCs. Effects of particle size and amount of different reinforcements like SiC, WC, Al2O3, TiB2, CNT, graphene nano platelets (GNP), graphite on tribological behaviour are discussed. Incorporation of nanoparticles generally enhances properties. Role of different fabrication processes like stir casting (SC), ultrasonic treatment casting (UST), disintegrated melt deposition (DMD), friction stir processing (FSP) on wear and friction behaviour of Mg-MNCs is also reviewed. Contributions of different tribological process parameters (sliding speed, load and sliding distance) on wear, friction and wear mechanism are also examined.

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