Auxetic materials
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The document discusses auxetic materials, which have a negative Poisson's ratio meaning they become larger when stretched rather than smaller. Auxetic materials can occur naturally in neutron stars, white dwarfs, and cat skin, and researchers are working to manufacture artificial versions that could have applications as artificial muscles, arteries, and structural connectors due to their increased shear stiffness, toughness, and indentation resistance compared to conventional materials.
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Auxetic Materials
Auxetic materials are known for their peculiar behavior unlike conventional materials the thickness of these materials increase under the action of axial pull. In this paper we are going to study the properties of Auxetic materials , their occurrence in nature, methods of synthesis, applications. Our ideas of other possibilities to make use of these materials. The current status of research into auxetic (negative Poisson's ratio) materials is reviewed, with particular focus on those aspects of relevance to aerospace engineering. Developments in the modelling, design, manufacturing, testing, and potential applications of auxetic cellular solids, polymers, composites, and sensor/actuator devices are presented. Auxetic cellular solids in the forms of honeycombs and foams are reviewed in terms of their potential in a diverse range of applications, including as core materials in curved sandwich panel Composite components, random applications, directional pass band filters, adaptive and deployable structures,MEMS devices, filters and sieves, seat cushion material, energy absorption components, viscoelastic, damping materials and fastening devices. In this paper we are going to put forward our proposals of using auxetic materials in helmet, seat of a bike, car bumpers.
PPT on laminated composite
This document provides an overview of laminated composite materials and refined plate theories used to model their behavior. It discusses how classical plate theory (CPT) and first-order shear deformation theory (FSDT) have limitations for thick laminated composites due to neglecting transverse shear effects. Higher-order theories like trigonometric shear deformation theory (TSDT), hyperbolic shear deformation theory (HSDT), and second-order shear deformation theory (SSDT) are introduced to address these limitations. The objectives of the study are to develop new refined theories, establish their credibility by applying them to static flexure problems, and obtain results for laminated beams and plates under various loadings not widely available in literature.
Micromechanics of Composite Materials
This document discusses the course MDPN452 Mechanics of Composite Materials, taught by Dr. Mohammad Tawfik. It covers topics related to micromechanics of composites including the relationship between composite and constituent material properties, designing composites to achieve desired stiffness and strength, assumptions of micromechanics models, approaches to determining elastic properties like stiffness and Poisson's ratio, and models for predicting strength in tension and compression. Students are assigned homework to research models of tensile and compressive failure in composites and compare them to experimental data.
Prepreg
Prepreg is reinforcing fabric pre-impregnated with epoxy resin and curing agent. It requires heat and pressure to cure the laminate. Prepregs offer advantages like maximum strength, uniform thickness, less mess and waste, and shorter curing times compared to hand-layup. However, prepregs cost more and have a limited shelf life requiring storage at cooler temperatures. Proper curing requires a heat source like an oven to reach 270F and sustain it for 4 hours under vacuum bagging.
Banana fiber reinforced composite material
This document discusses the preparation of a banana fiber reinforced composite wall material. Banana fibers are extracted from plantain stems and twisted into threads. The threads are arranged vertically and horizontally on a cardboard surface. Polyester resin, methyl ethyl ketone peroxide hardener, and silicon powder filler are mixed in a 60:10:30 ratio and poured into the fiber framework. The resulting composite wall has a tensile strength of 33 MPa and low thermal conductivity. Potential applications include automotive parts, and advantages of the natural fiber composite include being environmentally friendly and biodegradable. Future work proposed includes producing larger sheets and further testing mechanical properties.
Auxetics
Auxetic materials are any materials that thicken when stretched and thin when compressed, known as having a negative Poisson's ratio. They have high energy absorption and fracture resistance. Naturally occurring auxetic materials include single-crystal arsenic, catskin, and load-bearing bone. Current uses include pyrolytic graphite for aerospace thermal protection, Ni3Al in gas turbine vanes, and expanded PTFE for Gore-Tex. Possible future uses include prosthetics, surgical implants, filters, and bulletproof vests that take advantage of auxetic properties like energy absorption.
Filament winding نآمیرا فارسیمادان
An indepth description of filament winding and its fabrication.The slide has good understandability concepts that can be utilised for simple and effective presentation.
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The following presentation discusses challenges and solutions of composites testing, with a focus on standards, alignment, and strain.
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Auxetic Materials
Auxetic materials are known for their peculiar behavior unlike conventional materials the thickness of these materials increase under the action of axial pull. In this paper we are going to study the properties of Auxetic materials , their occurrence in nature, methods of synthesis, applications. Our ideas of other possibilities to make use of these materials. The current status of research into auxetic (negative Poisson's ratio) materials is reviewed, with particular focus on those aspects of relevance to aerospace engineering. Developments in the modelling, design, manufacturing, testing, and potential applications of auxetic cellular solids, polymers, composites, and sensor/actuator devices are presented. Auxetic cellular solids in the forms of honeycombs and foams are reviewed in terms of their potential in a diverse range of applications, including as core materials in curved sandwich panel Composite components, random applications, directional pass band filters, adaptive and deployable structures,MEMS devices, filters and sieves, seat cushion material, energy absorption components, viscoelastic, damping materials and fastening devices. In this paper we are going to put forward our proposals of using auxetic materials in helmet, seat of a bike, car bumpers.
PPT on laminated composite
This document provides an overview of laminated composite materials and refined plate theories used to model their behavior. It discusses how classical plate theory (CPT) and first-order shear deformation theory (FSDT) have limitations for thick laminated composites due to neglecting transverse shear effects. Higher-order theories like trigonometric shear deformation theory (TSDT), hyperbolic shear deformation theory (HSDT), and second-order shear deformation theory (SSDT) are introduced to address these limitations. The objectives of the study are to develop new refined theories, establish their credibility by applying them to static flexure problems, and obtain results for laminated beams and plates under various loadings not widely available in literature.
Micromechanics of Composite Materials
This document discusses the course MDPN452 Mechanics of Composite Materials, taught by Dr. Mohammad Tawfik. It covers topics related to micromechanics of composites including the relationship between composite and constituent material properties, designing composites to achieve desired stiffness and strength, assumptions of micromechanics models, approaches to determining elastic properties like stiffness and Poisson's ratio, and models for predicting strength in tension and compression. Students are assigned homework to research models of tensile and compressive failure in composites and compare them to experimental data.
Prepreg
Prepreg is reinforcing fabric pre-impregnated with epoxy resin and curing agent. It requires heat and pressure to cure the laminate. Prepregs offer advantages like maximum strength, uniform thickness, less mess and waste, and shorter curing times compared to hand-layup. However, prepregs cost more and have a limited shelf life requiring storage at cooler temperatures. Proper curing requires a heat source like an oven to reach 270F and sustain it for 4 hours under vacuum bagging.
Banana fiber reinforced composite material
This document discusses the preparation of a banana fiber reinforced composite wall material. Banana fibers are extracted from plantain stems and twisted into threads. The threads are arranged vertically and horizontally on a cardboard surface. Polyester resin, methyl ethyl ketone peroxide hardener, and silicon powder filler are mixed in a 60:10:30 ratio and poured into the fiber framework. The resulting composite wall has a tensile strength of 33 MPa and low thermal conductivity. Potential applications include automotive parts, and advantages of the natural fiber composite include being environmentally friendly and biodegradable. Future work proposed includes producing larger sheets and further testing mechanical properties.
Auxetics
Auxetic materials are any materials that thicken when stretched and thin when compressed, known as having a negative Poisson's ratio. They have high energy absorption and fracture resistance. Naturally occurring auxetic materials include single-crystal arsenic, catskin, and load-bearing bone. Current uses include pyrolytic graphite for aerospace thermal protection, Ni3Al in gas turbine vanes, and expanded PTFE for Gore-Tex. Possible future uses include prosthetics, surgical implants, filters, and bulletproof vests that take advantage of auxetic properties like energy absorption.
Filament winding نآمیرا فارسیمادان
An indepth description of filament winding and its fabrication.The slide has good understandability concepts that can be utilised for simple and effective presentation.
Composites Testing: Challenges & Solutions
The following presentation discusses challenges and solutions of composites testing, with a focus on standards, alignment, and strain.
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This document discusses various methods for producing composites, which are divided into open molding and closed molding. Open molding methods described include hand lay-up, spray-up, and filament winding. Closed molding methods include compression molding, pultrusion, vacuum bag molding, and vacuum infusion processing. Each method is briefly described in terms of its process, molds used, advantages, and typical products produced.
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This document discusses the history and chemistry of vulcanization and curing systems for rubber. Some key points include:
- Charles Goodyear discovered in 1839 that heating rubber with sulfur produced an elastic product that did not become sticky or brittle at high/low temperatures, launching the vulcanization process.
- Sulfur has remained the most important vulcanizing agent, though other chemicals have also been examined. Accelerators were later developed to speed up the vulcanization reaction.
- Efficient vulcanization systems using sulfur donors and accelerators produce vulcanizates with mainly mono- and disulfide crosslinks rather than unstable polysulfide crosslinks and pendant groups. This improves aging
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This document discusses natural fiber composites made from hemp. It notes that Henry Ford developed a plant-based car made from hemp in 1940. Today, companies like Ford are using hemp composites for parts like door trim panels and under-the-hood sound dampeners. Hemp fibers are cleaned, heated, and glued together with natural or synthetic resins to form composites. Composites made from hemp are lighter, more energy efficient to produce, and can replace plastics and some metals in vehicles and other applications. By 2010, it was anticipated that natural fibers would replace 20% of the fiberglass used in US cars.
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This document discusses opportunities and challenges for textile reinforced composites. It describes how textiles can be formed using various processes like weaving, knitting, braiding, and direct forming to create structures with multiple fiber orientations. Textiles are considered to have cost advantages over tape layup methods. However, shaping textiles to create tapered or complex geometries can introduce variations in fiber volume fraction, weave angle, yarn distribution, and mechanical properties across the structure. Careful design is required to minimize these variations.
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Banana Fiber Reinforced Composite Materials
The natural fibers are renewable, non-abrasive, bio-degradable, possess a good calorific value, exhibit excellent mechanical properties and are inexpensive.
This good environmental friendly feature makes the materials very popular in engineering markets such as the automotive and construction industry.
The banana fibers are waste product of banana cultivation, therefore without any additional cost these fibers can be obtained for industrial purposes.
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Different Load calculation.
Calculation of standard dimensions of drive like arc of contact, length of belt or chain, no. of links and etc.
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The document discusses drafting in textile manufacturing. It defines drafting as reducing the mass per unit length of sliver by passing it over rotating rollers of increasing speed. The drafting process involves three stages - break draft, main draft, and tension draft. In the main draft stage, where the bulk of drafting occurs, methods like aprons and pressure bars are used to control fibers. A roving frame inserts twist and winds the roving onto bobbins after drafting. Calculations are provided to determine the ratch, or distance between rollers, based on parameters like roller diameter, winding rate, and angular velocity. Drafting results in fibers becoming more compact and chemically stable with improved strength and lower moisture absorption.
Polymer Composites in Aviation Sector
Modern aerospace industry is highly progressive and polymer composite materials have a positive and significant impact on it. At least 30-40 percent of modern airframes are now made of these composites, and this percentage is increasing rapidly due to technological advances in this field. Fiber-reinforced polymer composite materials are fast gaining ground as preferred materials for construction of aircrafts and space crafts. This review paper demonstrates brief about the components of polymer composites, its properties and its uses in aerospace industries. Polymer composites are highly efficient and environment friendly. Traditional materials are susceptible to fatigue and corrosion when composite materials provide resistance to both of this along with its significant amount of weight reduction. Due to high strength and stiffness of its fiber, polymer composite provides high “strength to weight” & “stiffness to weight” ratios. Apart from this, they possess good shear properties and low density .As a result, new generation aerospace engineers and aircraft designers are turning to polymer composite materials to make their flying vehicle and aircraft lighter, stronger and of course more fuel efficient. A brief introduction of composites usage in aerospace sector is given first. The nature of Polymer composite materials and special problems in designing and working with them are then highlighted. The advantages and disadvantages of polymer composites in aviation sector is discussed.
Link for Related Research Paper: http://www.ijert.org/view-pdf/16992/polymer-composites-in-aviation-sector
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Shape memory materials have two crystal structures and can change between the structures through heating and cooling, allowing the material to remember its original shape. These materials are thermoplastic and display pseudo-elastic behavior, making them suitable for applications such as morphing wings, reusable molds, deployable mirrors, and portable bridges where the ability to change shape and remember the original is useful.
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This document discusses various methods for producing composites, which are divided into open molding and closed molding. Open molding methods described include hand lay-up, spray-up, and filament winding. Closed molding methods include compression molding, pultrusion, vacuum bag molding, and vacuum infusion processing. Each method is briefly described in terms of its process, molds used, advantages, and typical products produced.
Vulcanisation, accelerators & curing system
This document discusses the history and chemistry of vulcanization and curing systems for rubber. Some key points include:
- Charles Goodyear discovered in 1839 that heating rubber with sulfur produced an elastic product that did not become sticky or brittle at high/low temperatures, launching the vulcanization process.
- Sulfur has remained the most important vulcanizing agent, though other chemicals have also been examined. Accelerators were later developed to speed up the vulcanization reaction.
- Efficient vulcanization systems using sulfur donors and accelerators produce vulcanizates with mainly mono- and disulfide crosslinks rather than unstable polysulfide crosslinks and pendant groups. This improves aging
Natural fibre-composites
This document discusses natural fiber composites made from hemp. It notes that Henry Ford developed a plant-based car made from hemp in 1940. Today, companies like Ford are using hemp composites for parts like door trim panels and under-the-hood sound dampeners. Hemp fibers are cleaned, heated, and glued together with natural or synthetic resins to form composites. Composites made from hemp are lighter, more energy efficient to produce, and can replace plastics and some metals in vehicles and other applications. By 2010, it was anticipated that natural fibers would replace 20% of the fiberglass used in US cars.
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This document discusses repair of damage to aircraft structures using composites. It describes the advantages of composite repair over metallic repair, including lighter weight, higher strength, and easier field-level repair allowing improved aircraft availability. Various composite repair methods are presented, including injection repair, potting repair, and bonded or bolted patch repairs to restore structural integrity. The equipment and facilities needed for inspection, testing and performing composite repairs in the field or depot are also outlined. The conclusion recommends establishing field-level composite repair facilities to enhance aircraft turnaround rates.
Vacuum bag molding
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A brief presentation on Carbon Fiber and its applications by students of Ahsanullah University of Science and Technology (AUST)
Composite manufacturing processes
Hand lay up, pre-preg, pressure molding, vacuum bagging, filament winding, pultusion, spray method, sheet molding, bulk molding and resin transfer molding
Polyester fiber and its properties
Polyester is a synthetic polymer composed of at least 85% ester linkages between an alcohol and terephthalic acid. It exists in several forms including filament, staple, tow, and fiberfill, each used for different applications. Polyester is colorless, transparent, smooth, lustrous, and can take on various shapes. It is strong, resistant to stretching, shrinking, chemicals, and retains its shape well when wet or dry. Polyester is often blended with other fibers like cotton, wool, and rayon to improve durability and wrinkle resistance. It has a wide range of uses including clothing, home furnishings, and industrial products.
3D Braiding Technology & Application
3D braided fabrics are fabrics in which yarn runs through the braid in all three directions, formed by inter-plaiting three orthogonal sets of yarn.The fiber architecture of three-dimensional braided fabrics provides high strength, stiffness, and structural integrity, making them suitable for a wide array of applications. 3D fabrics can be produced via weaving, knitting, and non-weaving processes.
Bearing materials ...
The document discusses powder metallurgy bearing materials. It begins with a brief history of self-lubricating bearings developed in the 1920s. Common materials used include bronze, iron, and aluminum alloys which are porous and can be impregnated with oil to provide self-lubrication. The document outlines the manufacturing process and secondary operations like impregnation, machining, and coating. Self-lubricating bearings have advantages of reliability, low maintenance needs, and can operate under a range of loads and speeds. Selection of the proper bearing material is important for predictable wear performance and lifetime in different applications.
2. textile reinforced composites
This document discusses various types of textile reinforcements and composites materials, including woven, knitted, braided and stitched fabrics. It describes the components, classification, manufacturing processes and applications of composites. Specifically, it provides details on woven fabric-reinforced composites, their mechanical properties, and how they are widely used in aerospace applications. It also examines the Boeing 787 aircraft as a case study, outlining the technological and economic benefits of its extensive use of composite materials.
Mechanics of Composite Materials
This document discusses opportunities and challenges for textile reinforced composites. It describes how textiles can be formed using various processes like weaving, knitting, braiding, and direct forming to create structures with multiple fiber orientations. Textiles are considered to have cost advantages over tape layup methods. However, shaping textiles to create tapered or complex geometries can introduce variations in fiber volume fraction, weave angle, yarn distribution, and mechanical properties across the structure. Careful design is required to minimize these variations.
Textile composite testing
This document provides an overview of mechanical and non-destructive testing methods for composite materials. It discusses various mechanical tests including hardness, tensile, compression, impact, and fatigue tests. It also discusses non-destructive testing methods such as visual inspection, liquid penetrant, magnetic particle, eddy current, ultrasonic, and radiographic testing. The document provides details on procedures and purposes for many of the most common tests used to evaluate composite material properties and identify defects.
Banana Fiber Reinforced Composite Materials
The natural fibers are renewable, non-abrasive, bio-degradable, possess a good calorific value, exhibit excellent mechanical properties and are inexpensive.
This good environmental friendly feature makes the materials very popular in engineering markets such as the automotive and construction industry.
The banana fibers are waste product of banana cultivation, therefore without any additional cost these fibers can be obtained for industrial purposes.
Design of Flat Belt , V Belt and Chain Drive by Prof. Sagar Dhotare
Design Covers following points,
calculation of belt width and no, of plies with proper cross-section.
Different Load calculation.
Calculation of standard dimensions of drive like arc of contact, length of belt or chain, no. of links and etc.
Composites
Composites are materials made from two or more constituent materials with significantly different physical or chemical properties that remain separate and distinct at the macroscopic or microscopic level within the finished structure. Composites have improved strength, stiffness, and other properties over the individual constituent materials alone. Common composite materials include fiberglass and carbon fiber reinforced plastics. Composites are used in a wide range of industries including construction, transportation, aerospace, and consumer goods due to their high strength to weight ratio and ability to be tailored to specific applications.
Prepreg technology[1]
Prepreg technology has enabled the evolution of high-speed transportation like trains and ships. This document explains prepreg technology, including how prepregs are made and their properties. Prepregs consist of fibers reinforced with a resin or matrix. They are used in aerospace, marine, sports, and other industries due to benefits like lower weight, higher strength and stiffness than conventional materials. Common prepreg processing methods include vacuum bagging and autoclaving.
Drafting Of Yarn
The document discusses drafting in textile manufacturing. It defines drafting as reducing the mass per unit length of sliver by passing it over rotating rollers of increasing speed. The drafting process involves three stages - break draft, main draft, and tension draft. In the main draft stage, where the bulk of drafting occurs, methods like aprons and pressure bars are used to control fibers. A roving frame inserts twist and winds the roving onto bobbins after drafting. Calculations are provided to determine the ratch, or distance between rollers, based on parameters like roller diameter, winding rate, and angular velocity. Drafting results in fibers becoming more compact and chemically stable with improved strength and lower moisture absorption.
Polymer Composites in Aviation Sector
Modern aerospace industry is highly progressive and polymer composite materials have a positive and significant impact on it. At least 30-40 percent of modern airframes are now made of these composites, and this percentage is increasing rapidly due to technological advances in this field. Fiber-reinforced polymer composite materials are fast gaining ground as preferred materials for construction of aircrafts and space crafts. This review paper demonstrates brief about the components of polymer composites, its properties and its uses in aerospace industries. Polymer composites are highly efficient and environment friendly. Traditional materials are susceptible to fatigue and corrosion when composite materials provide resistance to both of this along with its significant amount of weight reduction. Due to high strength and stiffness of its fiber, polymer composite provides high “strength to weight” & “stiffness to weight” ratios. Apart from this, they possess good shear properties and low density .As a result, new generation aerospace engineers and aircraft designers are turning to polymer composite materials to make their flying vehicle and aircraft lighter, stronger and of course more fuel efficient. A brief introduction of composites usage in aerospace sector is given first. The nature of Polymer composite materials and special problems in designing and working with them are then highlighted. The advantages and disadvantages of polymer composites in aviation sector is discussed.
Link for Related Research Paper: http://www.ijert.org/view-pdf/16992/polymer-composites-in-aviation-sector
Fiber Reinforced Plastic
Fibre-reinforced plastic (FRP) is a composite material made of a polymer matrix reinforced with fibres like glass, carbon, aramid, or basalt. The fibres mechanically enhance the strength and elasticity of the plastic matrix. Commonly used fibres include glass for strength and light weight, carbon for high strength and stiffness, and aramid for heat resistance and strength. FRP has properties like low expansion, high strength, heat stability, and toughness making it suitable for applications in aerospace, automotive, equipment, and insulation.
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Plastic lumber-technology
The document discusses the manufacturing process and applications of plastic lumber. Plastic is made from high density polyethylene and molded into products like railroad ties and bridges. Railroad ties last longer than wood and are more cost effective over time, with 15 million wood ties being replaced yearly. A plastic bridge in Missouri was the first to support vehicle traffic, replacing a wooden bridge at a lower cost. While plastic has lower stiffness and strength than wood in extreme temperatures, it holds fasteners similarly to wood and weighs about the same.
Photovoltic solar-cell
Solar cells have existed since 1839 but were not practical until the 1970s energy crisis sparked interest. Now solar cells are used in building integrated photovoltaics (BIP) by placing solar panels on walls, roofs, and in transparent "power glass." BIP uses a thin film coating applied via a reel-to-reel process to turn conventional glazing into electricity-generating material. BIP has applications in windows, atriums, roofs, and curtain walls, making it especially useful for commercial and industrial facilities.
Nomex 2
NOMEX is a flame and heat resistant long chain polyamide fiber made from meta-phenylenediamine and isophthaloyl chloride. It is spun into fibers and formed into sheets that can be made into honeycomb shapes. NOMEX has a wide variety of uses including heat and electrical insulation, automotive, aviation, protective apparel, and firefighting gear due to its flame resistant and lightweight properties.
Nitrile rubber
The document discusses nitrile rubber, which is a polymeric mixture of butadiene and acrylonitrile in a 2:1 ratio. Higher levels of acrylonitrile yield properties like low temperature flexibility and increased hardness. Nitrile rubber is a highly polar elastomer that exhibits large and reversible elastic deformation. It has excellent tensile strength, elongation, low temperature flexibility, compression set, tear resistance, and abrasion resistance. However, it has fair to poor flame resistance and gas permeability.
Nickel titanium-alloys
Shape memory alloys, specifically nickel titanium, were first observed in the 1930s and can remember their original shape. They have two solid phases and are commonly used today in medical devices, appliances, and safety devices. Potential future applications include use in car and airplane engines, car frames, engine cooling, and engine lubrication controls due to shape memory alloys' ability to remember their original shape.
Nanotubes
This document discusses carbon nanotubes, which are cylindrical shells of graphitic carbon that were discovered in 1991. It has three main sections: the first provides a definition and potential applications of carbon nanotubes, the second discusses the history of discoveries related to carbon nanotubes, and the third outlines current and potential future technological uses, including for space exploration, electronics, and energy storage.
Nanotube
Nanotubes are flat layers of graphite rolled into tubes. They can be single-walled or multi-walled, and have different configurations including armchair, zigzag, and chiral. Nanotubes have exceptional properties such as high tensile strength, elasticity, density, thermal and electrical conduction, and chemical inertness. Potential applications of nanotubes include using them to reinforce composites, in electrical fields, and in fuel cells.
Nanomachines
Nanomachines are mechanical or electromechanical devices that are measured in nanometers, which are units of 10-9 meters or millionths of a millimeter. K. Eric Drexler popularized the idea of nanomachines in the 1980s and 1990s, with the goal of building an "assembler" nanomachine that can manipulate individual atoms to rearrange raw materials and produce useful items. The main engineering challenge is gaining control over molecular engineering and chemical synthesis to be able to position individual atoms and form new stable molecular structures like simulated nanogears.
Micro electro-mechanical-systems-mems
MEMS stands for micro-electro-mechanical systems, which involves integrating sensors, actuators, and electronics onto a common silicon substrate using microfabrication technology. MEMS can be made from materials like gallium arsenide, titanium nickel, and piezoelectric materials. The main steps in fabricating MEMS are deposition, lithography, and etching - which allow for creating thin films and precisely etching patterns. In the future, MEMS technology is expected to enable cost reduction, increased functionality, improved reliability, decreased size, and decreased mass compared to conventional technologies.
Metal rubber
Metal Rubber is a unique nanocomposite material that combines the high electrical conductivity of metals with the low mechanical modulus of elastomers. The self-assembly process allows simultaneous modification of both conductivity and modulus during manufacturing. Metal Rubber has a maximum electrical conductivity of 5x10-6 W cm and can elongate up to approximately 200%. Electrical conductivity varies slightly with elongation.
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Auxetic materials
- 2. Ratio of axial and lateral strains Formulated so most materials with positive value =ν - xЄ = - yЄ z zЄ Є
- 3. Materials with a negative Poisson Value Density may vary from one-trillionth the density of air or 100 billion times air Formed -460*F or 10,000+ heat of white dwarf stars
- 4. Auxetic materials Larger when stretched Smaller when compressed Normal materials Smaller when stretched Larger when compressed
- 8. Nature Neutron stars White dwarf Skin of a cat Manufactured (still under research) Artificial muscles Artificial arteries Structural connectors
- 9. Increased shear stiffness Increased plane strain fracture toughness Increased indentation resistance Superior to conventional materials for many practical applications
- 10. Increased shear stiffness Increased plane strain fracture toughness Increased indentation resistance Superior to conventional materials for many practical applications