Engineering Materials and Processes Lecture 2 –...
Transcript of Engineering Materials and Processes Lecture 2 –...
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www.highered.tafensw.edu.au
Engineering Materials and ProcessesLecture 2 – Material Properties
PresenterPresentation NotesPrescribed Text: Ref 1: Higgins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. ISBN: 9781856177696 Readings:Callister: Callister, W. Jr. and Rethwisch, D., 2010, Materials Science and Engineering: An Introduction, 8th Edition, Wiley, New York. ISBN 9780470419977Ashby 1: Ashby, M. & Jones, D., 2011, Engineering Materials 1: An Introduction to Properties, Applications and Design, 4th edition, Butterworth-Heinemann, Oxford UK. IBSN: 9780080966656Ashby 2: Ashby, M. & Jones, D., 2011, Engineering Materials 2: An Introduction to Microstructures and Processing, 4th edition, Butterworth-Heinemann, Oxford UK. IBSN: 9780080966687 Lecture (2 hrs): Ref 1, Ch 1: Engineering materials;Ref 1 Ch 2: Properties of materials. Laboratory 1 (2 hrs): Hardness testReadings: Callister: Ch 1, 2, 18-21Ashby 1: Ch 1, 2 Ashby 2: Ch 1
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Properties of Materials
EMMAT101A Engineering Materials and Processes
Reference Text SectionHiggins RA & Bolton, 2010. Materials for Engineers and Technicians
Ch 2
Additional Readings SectionSheedy, P. A, 1994. Materials : their properties, testing and selection
Ch 3, Ch5
Callister, W. Jr., 2010, Materials Science and Engineering Ch7
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PropertiesA property is characteristic of a material. It should be about the same for any piece of the material.
Some properties can be measured easily, others may require breaking a specimen.
EMMAT101A Engineering Materials and Processes
PROPERTY NOT A PROPERTYDensity MassStiffness LengthHardness WearStrength Force
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Example Properties
• Hardness: Diamond, Hardened Steel
• Density: Plutonium, Lead
• Toughness: Mild Steel, Kevlar
• Elasticity: Rubber, steel, glass(!)
• Ductility: Plastics, Nickel, Copper,
• Conductivity: Silver, Copper, Aluminum
• Resistivity: Plastics, Glass, Ceramics
• Linear Expansion Coeff: Polyethylene
• Corrosion Resistance: Ceramics, titanium, polymers
EMMAT101A Engineering Materials and Processes
HARDNESSBall Bearing SKF
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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Classes of Properties• Mechanical properties: most are related to forces applied to the material, e.g. strength, stiffness, hardness, toughness… • Electrical properties: resistivity, conductivity• Magnetic properties:• Thermal properties: expansion, heat capacity.• Optical properties: transparency, refractive index.• Aesthetic properties: appearance, texture.• Chemical properties: reactivity, corrosion resistance, chemical compatibility, degradation.
EMMAT101A Engineering Materials and Processes
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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Basic Formulas 1Density (kg/m3) = Mass (kg) / Volume (m3)
ρ = m / V
EMMAT101A Engineering Materials and Processes
Varies with temperature;• Slightly for solids.• About x10 for liquids.• By gas law for gases.
Material ρ (kg/m3)Air 1.2
Styrofoam 75Cork 240Ice 916.7
Water (fresh) 1,000Aluminium 2,700Titanium 4,540
Iron 7,870Lead 11,340
Tungsten 19,300
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
http://en.wikipedia.org/wiki/Airhttp://en.wikipedia.org/wiki/Styrofoamhttp://en.wikipedia.org/wiki/Cork_(material)http://en.wikipedia.org/wiki/Icehttp://en.wikipedia.org/wiki/Waterhttp://en.wikipedia.org/wiki/Aluminiumhttp://en.wikipedia.org/wiki/Titaniumhttp://en.wikipedia.org/wiki/Ironhttp://en.wikipedia.org/wiki/Leadhttp://en.wikipedia.org/wiki/Tungsten
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Basic Formulas 1Density (kg/m3) = Mass (kg) / Volume (m3)
ρ = m / V
EMMAT101A Engineering Materials and Processes
Varies with temperature;• Slightly for solids.• About x10 for liquids.• By gas law for gases.
DENSITY INCREASES AS VOLUME DECREASESTim Lovett
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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Basic Formulas 2Stress (MPa) = Force (N) / Area (mm2)
σ = F / A
Tensile Stress: PullingCompressive Stress: SquashingShear Stress: Sliding
EMMAT101A Engineering Materials and Processes
Tensile StressTim Lovett
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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Basic Formulas 3Strain () = Elongation (mm) / Original Length (mm)
ε = e / Lo
Strain has no units.Low elastic strain in metals.
EMMAT101A Engineering Materials and Processes
Elongation
ElongationTim Lovett
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
http://www-materials.eng.cam.ac.uk/mpsite/properties/non-IE/elongation.html
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Basic Formulas 4Stiffness (Mpa) : Stress (Mpa) / Strain ()
E = σ / ε
Many names; Young’s Modulus Modulus of Elasticity Stiffness Modulus Modulus !
Usually a BIG number (GPa)
EMMAT101A Engineering Materials and Processes
Higgins 2.2.1 Table 2.1
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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Mechanical PropertiesStrength: Ability to endure stress – the intensity of force.
Stress (Pa) = Force (N) / Area (m2)
σ = F / A
Ultimate Strength: Highest stress without breakage. Yield Strength: Highest stress without deformation.
EMMAT101A Engineering Materials and Processes
TENSILE STRESSTL
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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EMMAT101A Engineering Materials and Processes
Mechanical test of the strength of mild steel.
Stress / Strain Curve for Mild SteelTim Lovett
www.nmu.edu
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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EMMAT101A Engineering Materials and Processes
Stress / Strain Curve for Mild SteelTim Lovett
Yield StrengthYS
Ultimate Tensile StrengthUTS
Mechanical test of the strength of mild steel.
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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EMMAT101A Engineering Materials and Processes
Alternative to Yield PointYield point. A levelling off on the stress-strain curve as plastic deformation begins.
1.True elastic limit: The first hint of atomic slip. Hard to measure because some atoms move easily.2. Proportionality limit: End of straight line (Hooke's law).3. Elastic limit (yield strength) Where permanent deformation will occur. The lowest stress at which permanent deformation can be measured. This requires a manual load-unload procedure, and the accuracy is critically dependent on equipment and operator skill. 4. Proof Stress (Offset yield point). When a yield point is not easily defined.
Alternative Yield definitions for materials that do not exhibit a well-defined yield point.Wikipedia
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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EMMAT101A Engineering Materials and Processes
Proof Stress as alternative to Yield StressTim Lovett
Proof Stress (Offset yield point) Some materials do not show an obvious yield point. E.g. high strength steels and aluminium.In this case, an offset yield point is used, with an offset of 0.1 or 0.2% of the strain.
The real elastic limit…You have an unknown material and a tensile tester. How do you find the yield point.
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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Stress grade 8.8 embossed on bolt head.
EMMAT101A Engineering Materials and Processes
Hydraulic tensioning of foundation bolts of wind turbine tower.
Nut torquingwww.torcup.com
Grade 8.8 BoltHebei Saite Fastener Co., Ltd.
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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Stress grade 8.8 embossed on bolt head.
EMMAT101A Engineering Materials and Processes
4.6 = 400 Mpa and 60% YS8.8 = 800 Mpa and 80% YS10.9 = 1000 Mpa and 90% YS12.9 = 1200 Mpa and 90% YS
Grade 8.8 BoltHebei Saite Fastener Co., Ltd.
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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Stress grades of bolts.
EMMAT101A Engineering Materials and Processes
4.6 = 400 Mpa and 60% YS8.8 = 800 Mpa and 80% YS10.9 = 1000 Mpa and 90% YS12.9 = 1200 Mpa and 90% YS
Grade 8.8 BoltHebei Saite Fastener Co., Ltd.
Higher grade bolts have lower ductility.
Tim Lovett
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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EMMAT101A Engineering Materials and Processes
Tensile Strength (UTS) values for different materials.
Higgins 2.2.1 Table 2.1 Tensile Test on PlasticIntertek Plastics: http://www.ptli.com
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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EMMAT101A Engineering Materials and Processes
Tensile tests are usually done on prepared specimens.
A narrowed section is where the stress is calculated, otherwise the specimen will break where it is gripped.
“Necking” occurs on ductile materials after reaching the UTS.“Cup and cone” fracture indicates ductility
Tensile Test specimensmetassoc.com
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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EMMAT101A Engineering Materials and Processes
Comparison of Tensile Strength of Steels (UTS) As steels get stronger they get more brittle.
American Iron and Steel Institute: AISI
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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EMMAT101A Engineering Materials and Processes
Typical materials diagram by Ashby. (c) Copyright Granta Design Ltd, Cambridge, Englandwww.grantadesign.com. Reproduction Permission?
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
http://www.grantadesign.com/
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EMMAT101A Engineering Materials and Processes
Stress/Strain curve showing elastic and plastic regions.
Stress / Strain Curve for Mild Steel showing elastic/plastic regions.
Typical curve for mild steel.
This curve shows engineering stress – based on original cross-sectional area.
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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EMMAT101A Engineering Materials and Processes
Wikipedia.
True stress (B) is higher than engineering stress (A). Due to decreasing area.
True Stress = Force / Actual area
Engineering usually based on original area because this will determine strength in service.
1 = UTS Ultimate Tensile Strength2 = YS Yield Strength3 = Engineering fracture Stress4 = Work Hardening5 = Necking
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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Factor of SafetyHow many times you could multiply the working stress before it breaks.
FS = ultimate strength / working stress
Use High FS when: Dangerous, unknown loads. E.g. Lifting gear.Low FS: Very accurate knowledge of problem, optimum weight / cost / size. E.g. Bridge.
28kN carabiner designed to hold a human (100kg).FS = 24 !Extremely high FS accounts for shock loading.
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EMMAT101A Engineering Materials and Processes
Force ratings engraved on Aluminium karabiner. 28kN closed, 10kN open, 8kN sideways
Karabiner Edelrid.de
Wind Turbine Repair wwww.ropepartner.com
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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EMMAT101A Engineering Materials and Processes
A European standard shows minimum force. 20kN closed, 7kN open, 7kN sideways. (UIAA 121)
Karabiner Edelrid.de UIAA standards for the minimum strength of a carabinerhttp://www.crabdev.co.uk/comp%20introduction.htm
Edelrid: 28kN closed, 10kN open, 8kN sideways
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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EMMAT101A Engineering Materials and Processes
Force increased beyond ultimate stress of turbine blades, causing catastrophic failure.
Turbine Collapse
Wind Turbine Collapse www.spiegel.de
http://www.youtube.com/watch?v=CqEccgR0q-o
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EMMAT101A Engineering Materials and Processes
Bolted joints in critical applications in a wind turbine. Bolts are designed for a certain stress.Torque rating (Nm) used to convert to pulling force (clamping force) of bolt.
Torqup.com
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StiffnessStiffness (Mpa) = Stress (Mpa) / Strain ()
E = σ / εMany names; Young’s Modulus Modulus of Elasticity Stiffness Modulus Modulus !
EMMAT101A Engineering Materials and Processes
Carbon fibre is very light and stiff. This bike fork uses carbon
and magnesium. A carbon crown and steerer with a carbon fibre
wrapped magnesium lower.www.bikerumor.com
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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EMMAT101A Engineering Materials and Processes
Stiffness EStiffness: The stress that will stretch a material by a certain amount.
Stiffness is defined in the elastic region (before the yield point), as the slope of the stress/strain curve. Since strain has no units, stiffness is same as stress (MPa)
Engineering materials frequently have a modulus of the order of 1000 000 000 Pa, i.e. 109 Pa. This is generally expressed as GPa, with 1 GPa = 109 Pa.
Higgins 2.2.1 Table 2.1
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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EMMAT101A Engineering Materials and Processes
Stiffness is the slope of the Stress/Strain curve – up to the yield point.
Stress / Strain Curve for Mild SteelTim Lovett
Stiffness = Stress / Strain= 500 / 0.25%= 200000 Mpa= 200 GPa
Stiffness is a reliable and predictable property. Steels are all about 200GPa regardless of strength or hardness.
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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EMMAT101A Engineering Materials and Processes
Stiffness vs Density.
Stiff materials tend to be heavy. Composites have fairly high stiffness but almost as light as polymers.
Stress / Strain Curve for Mild SteelTim Lovett
http://www-materials.eng.cam.ac.uk/mpsite/interactive_charts/stiffness-density/basic.html
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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DuctilityDuctility: this is the ability of a material to deform without breaking.The opposite to ductile is Brittle. (Like glass)Ductility allows forming processes (like pressing, wire drawing)Measured as percent elongation: How far it has stretched compared to the original length.
% elongation = L x 100 / Lo
EMMAT101A Engineering Materials and Processes
Tim Lovett
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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Ceramics are brittle – zero elongation, which means they have no plastic deformation.
EMMAT101A Engineering Materials and Processes
Higgins Table 2.3
Plasticity: permanent deformationDuctility: tensile plasticityMalleability: compressive plasticity
Some plastics have % elongation of 500% or more.
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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ToughnessEnergy to break. (Joules)
EMMAT101A Engineering Materials and Processes
Charpy Impact Test measures energy absorbed by impact and breaking of specimen.
A brittle material will hardly slow down the hammer, a tough material will almost halt it.
Toughness usually decreases at lower temperatures.
Toughness usually decreases with higher impact speed.
CHARPY IMPACT TEST: Tim Lovett
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ToughnessEnergy to break. (Joules)
EMMAT101A Engineering Materials and Processes
A tough material:• resists a crack running through the material (fracture toughness).• absorbs more energy as crack runs through it.• will have ductility
Fracture Toughness: Wikipedia
Type Material KIc (MPa · m1/2)
Metals
Aluminum alloy (7075)Steel alloy (4340) 50Titanium alloy 44–66Aluminum 14–28
Ceramic
Aluminium oxide 3–5Silicon carbide 3–5Soda-lime glass 0.7–0.8Concrete 0.2–1.4
Polymer Polymethyl methacrylate 0.7–1.6
Polystyrene 0.7–1.1Composit
eMullite-fibre composite 1.8–3.3
Silica aerogels 0.0008–0.0048
http://en.wikipedia.org/wiki/Aluminumhttp://en.wikipedia.org/wiki/Steelhttp://en.wikipedia.org/wiki/Titaniumhttp://en.wikipedia.org/wiki/Aluminium_oxidehttp://en.wikipedia.org/wiki/Silicon_carbidehttp://en.wikipedia.org/wiki/Soda-lime_glasshttp://en.wikipedia.org/wiki/Concretehttp://en.wikipedia.org/wiki/Polymethyl_methacrylatehttp://en.wikipedia.org/wiki/Polystyrenehttp://en.wikipedia.org/wiki/Mullitehttp://en.wikipedia.org/wiki/Aerogel
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EMMAT101A Engineering Materials and Processes
Toughness/Strength
For the engineering materials, increasing the strength tends to DECREASE toughness.
The ultimate engineering material has both strength and toughness.
This is why composites appear in the high performance areas:Tough, Strong and Light.
http://www-materials.eng.cam.ac.uk
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EMMAT101A Engineering Materials and Processes
Composites used for toughness, strength and light weight.
Record 75m long turbine blade: Siemens press picture.
http://www.siemens.com/press/en/presspicture/?press=/en/presspicture/pictures-photonews/2012/pn201204.php
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HardnessResistance to indentation or abrasion. (no units)
EMMAT101A Engineering Materials and Processes
There are several types of hardness tests:• Brinell (Ball indentor. Measure diameter of dent)• Vickers (Pyramid diamond indentor. Measure dent)• Rockwell…
BRINELL: www.twi.co.ukVICKERS: www.twi.co.uk
PresenterPresentation NotesIndentation (plastic deformation)Abrasion (brittle materials – ceramics)
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Rockwell Hardness Test
EMMAT101A Engineering Materials and Processes
• Fast and simple test.• Various scales for hard/soft materials
ROCKWELL HARDNESS TEST: Tim Lovett
ROCKWELL HARDNESS TEST: Tim Lovett
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Mechanical Properties Summary
Strength (Mpa) : Ability to endure stress – the intensity of force.
Strain () Elastic = Elongation (mm) / Original Length (mm)
Elongation (%) Plastic = Elongation (mm) / Original Length (mm)
Stiffness (Mpa) : Stress to cause strain = Stress (Mpa) / Strain ()
Toughness (J) : Energy to break
Hardness () : Resistance to indentation / abrasion.
EMMAT101A Engineering Materials and Processes
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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Mechanical Properties Definitions Ductility: The ability of a material to deform plastically before fracture.
% Elongation: Plastic deformation determined after fracture by realigning and fitting together the broken ends of the specimen.
Engineering strain: Change in length / original length
Strength: Ability to endure stress – the intensity of force.
UTS Ultimate tensile strength or tensile strength: The maximum tensile stress that a material is capable of sustaining. (original area)
Yield strength: The engineering stress at which, by convention, it is considered that plastic elongation of the material has commenced.
Stiffness: Stress required to give a certain strain.
Toughness (J) : Energy to break
Hardness () : Resistance to indentation / abrasion.
EMMAT101A Engineering Materials and Processes
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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EMMAT101A Engineering Materials and Processes
Information that can be determined from the Stress/Strain curve…
Stress / Strain Curve for Mild Steel showing elastic/plastic regions.
1. Ductility2. Elongation3. Engineering
strain4. Strength5. UTS6. YS7. Stiffness
Toughness
8. Hardness? Not directly, but correlates with strength. E.g. High strength steels are harder.
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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Electrical PropertiesResistivity (ohm.m): ρ is an electrical property defined by the equation;
where R = resistance (ohms), L = length (m), A = sectional area (m2)
An electrical insulator, (e.g. ceramic) has high resistivity. (1010 Ωm)
An electrical conductor, (e.g. copper), has low resistivity, (10"8 Ωm).
Conductivity is the reciprocal of resistivity.
EMMAT101A Engineering Materials and Processes
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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Resistivity (ohm.m):
EMMAT101A Engineering Materials and Processes
Higgins
Ceramics and polymers are insulators.
Metals are conductors
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 2.4
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Thermal Property αThe coefficient of linear expansion (α): The proportion a material expands with temperature. (mm/mmK)
ε = α ∆T∆T = change in temperature
ε = strain (thermal)α = coefficient of thermal expansion
EMMAT101A Engineering Materials and Processes
Bridges expand with temperature, so an expansion joint is needed on one end.Sydney Harbour Bridge
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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Thermal Property c Specific Heat Capacity (c): The amount of heat needed to
heat 1 kg of the material by 1 K. (J/kgK)
c = H / (m ∆T)∆T = change in temperature (K)
m = mass (kg)Η = heat (Joules)
EMMAT101A Engineering Materials and Processes
Radiator: Water has a high Specific Heat which is why it is used as the basis of cooling fluid.hgvdirect.co.uk
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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The term Thermal Mass can also mean heat capacity.
EMMAT101A Engineering Materials and Processes
Reverse Brick Veneer:
A traditional brick veneer building has a brick wall on the outside and a stud wall inside. The insulation is inside the wall lining (plasterboard).
With reverse brick veneer, the thermal mass (heat capacity) of the brickwork moderates the internal temperature without the impacts of the external weather conditions.
ruralbuilding.com.au
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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EMMAT101A Engineering Materials and Processes
Hydrogen has a very high c = 14.8. It is used as the working fluid in this Stirling engine generator. These generators achieved 31% solar-to-grid efficiency. However, there are more working parts than a photovoltaic system. sandia.gov
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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EMMAT101A Engineering Materials and Processes
Demonstration: Low temperature Stirling engine. Working fluid = air.
Friction is very low, so it can run on small temperature difference. For higher power (to run something useful) needs a higher temperature difference such as solar concentrator (below).
Low Temp Stirling Engine: ministeam.comsolarthermalmagazine.com
PresenterPresentation NotesDemonstration: Low temperature Stirling engine. Explain how power related to temp difference.
http://www.youtube.com/watch?v=n-mKP9E6a6I
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Thermal Property λThermal conductivity λ : the ability to conduct heat.Defined as Heat flowrate / temp gradient.
W / (mK): Watts per metre-Kelvin
EMMAT101A Engineering Materials and Processes
Insulation: Glass has a low thermal conductivity. roofperf.com.au
Aluminium Heat sink: High thermal conductivity. Wikipedia
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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Thermal Properties SummarySummary of thermal properties.
For metals, good thermal conductors tend to be good electrical conductors. (E.g. copper)
EMMAT101A Engineering Materials and Processes
Higgins
PresenterPresentation NotesHiggins RA & Bolton, 2010. Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. Ch 1.2.1
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Ashby Charts Select chart: Young's modulus - Density Young's Modulus - Cost Strength - Density Strength - Toughness Strength - Elongation Strength - Cost Strength - Max service temperature Specific stiffness - Specific strength Electrical resistivity - Cost Recycle Fraction - Cost Energy content - Cost
http://www-materials.eng.cam.ac.uk
http://www-materials.eng.cam.ac.uk/mpsite/interactive_charts/stiffness-density/default.htmlhttp://www-materials.eng.cam.ac.uk/mpsite/interactive_charts/stiffness-cost/default.htmlhttp://www-materials.eng.cam.ac.uk/mpsite/interactive_charts/strength-density/default.htmlhttp://www-materials.eng.cam.ac.uk/mpsite/interactive_charts/strength-toughness/default.htmlhttp://www-materials.eng.cam.ac.uk/mpsite/interactive_charts/strength-ductility/default.htmlhttp://www-materials.eng.cam.ac.uk/mpsite/interactive_charts/strength-cost/default.htmlhttp://www-materials.eng.cam.ac.uk/mpsite/interactive_charts/strength-temp/default.htmlhttp://www-materials.eng.cam.ac.uk/mpsite/interactive_charts/spec-spec/default.htmlhttp://www-materials.eng.cam.ac.uk/mpsite/interactive_charts/resistivity-cost/default.htmlhttp://www-materials.eng.cam.ac.uk/mpsite/interactive_charts/recycling-cost/default.htmlhttp://www-materials.eng.cam.ac.uk/mpsite/interactive_charts/energy-cost/default.htmlhttp://www-materials.eng.cam.ac.uk/mpsite/interactive_charts/strength-density/NS6Chart.html
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EMMAT101A Engineering Materials and Processes
Online Properties Resources.
Testlopedia: Testing of plastics
Graphical comparison of materials properties.
Wikipedia: Materials properties
• Composite carabiner study: http://www.crabdev.co.uk/comp%20introduction.htm
Searchable listing of material properties.
PresenterPresentation Noteshttp://www.matweb.comShow this website on screen. Will be using this later.
http://www.matweb.com/http://www-materials.eng.cam.ac.uk/mpsite/interactive_charts/strength-density/NS6Chart.htmlhttp://www.ptli.com/list.asphttp://en.wikipedia.org/wiki/List_of_materials_properties
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GLOSSARYStrengthStiffnessToughnessElongationStrainMalleabilityDuctilityResilienceYield StrengthUltimate Tensile StrengthFactor of SafetyHardnessCoeff of thermal expansionSpecific Heat CapacityThermal Conductivity
PresenterPresentation Noteshttp://www.youtube.com/watch?v=1GFst2IQBEM
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QUESTIONS
1. Discuss the variables that control the heat transfer through a solid material.2. Why are long steam supply lines built with a loop at regular intervals along their length? What other methods could be used?3. Explain what is meant by high thermal mass. 4. What is a refractory material? Give examples.5. What is the effect of temperature on the resistivity of a conductor?6. What are wind turbine blades made of? Explain why this material is used. List some alternatives.7. Explain the concept of reverse brick veneer. List advantages/disadvantages. What alternatives could achieve a similar outcome?8. Give examples of components of a wind turbine that require properties of: strength, toughness, hardness, stiffness.9. Give examples of components of a solar Stirling engine generator that require properties of: strength, toughness, hardness, thermal conductivity, heat capacity, electrical conductivity.
PresenterPresentation Noteshttp://www.youtube.com/watch?v=1GFst2IQBEM
Engineering Materials and Processes�Lecture 2 – Material PropertiesProperties of MaterialsPropertiesSlide Number 4Classes of PropertiesBasic Formulas 1Basic Formulas 1Basic Formulas 2Basic Formulas 3Basic Formulas 4Mechanical PropertiesSlide Number 12Slide Number 13Slide Number 14Slide Number 15Slide Number 16Slide Number 17Slide Number 18Slide Number 19Slide Number 20Slide Number 21Slide Number 22Slide Number 23Slide Number 24Factor of SafetySlide Number 26Slide Number 27Slide Number 28Slide Number 29StiffnessSlide Number 31Slide Number 32Slide Number 33DuctilitySlide Number 35ToughnessToughnessSlide Number 38Slide Number 39HardnessSlide Number 41Mechanical Properties SummaryMechanical Properties DefinitionsSlide Number 44Electrical PropertiesSlide Number 46Thermal Property aThermal Property cSlide Number 49Slide Number 50Slide Number 51Thermal Property lThermal Properties SummaryAshby ChartsSlide Number 55Slide Number 56Slide Number 57