muffler design and analysis

7/30/2019 Muffler design and analysis

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Introduction To Materials Science, Chapter 1, Introduction

University of Virginia, Dept. of Materials Science and Engineering 1

Spring 2001 MSE 209 - Section 6

Instructor: Leonid Zhigilei

Tuesday, Thursday, 9:30 AM - 10:45 AMOlsson Hall 005

MSE 209: Introduction to the Science

and Engineering of Materials


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Instructor: Leonid Zhigilei

Office: Materials Science Building 227

Office Hours: 11:00 am to 12:00 pm Monday, Friday& open

Telephone: (804) 243 3582E-mail: [email protected]

Class web page:

http://www.people.virginia.edu/~lz2n/mse209/

Class e-mail list: [email protected]

Graduate Teaching Assistants:

Contact Information:

982-5689hw2eJason Wang

982-5689cts2vTom SchampaishaAisha Moore

eemrBrian Mays

PhoneE-mail


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! Homework: 20%! Three 1 hour tests: 50 %

! The final exam: 30%

Homework: 11 problem sets will be will be assignedand will be due at the beginning of class one week

after assignment. Homework solutions should be neatand stapled. Homework does not require the pledgeand cooperation among students is permitted.

Late homework is not accepted

Tests: pledged, closed-book and closed-notes

Grading:

W. D. Callister, Materials Science and Engineering:

An Introduction (John Wiley 1999, 5th edition)

I will also post my lecture notes on the web.

Textbook:


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Types of materials (metals, ceramics, polymers,semiconductors)

Properties of materials (mechanical, thermal,

electrical, optical)

Different levels of structure in materials (atomic,

microscopic, macroscopic)

Relation among material processing, structure,properties, and performance

The main objective is to understand the basic concepts

and language of Materials Science

Syllabus:


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Historical PerspectiveStone Bronze Iron Advanced materials

What is Materials Science and Engineering ?

Processing Structure Properties Performance

Classification of MaterialsMetals, Ceramics, Polymers, Semiconductors

Advanced MaterialsElectronic materials, superconductors, etc.

Modern Material's Needs, Material of FutureBiodegradable materials, Nanomaterials, Smart materials

Chapter Outline


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Beginning of the Material Science - People began to

make tools from stone Start of the Stone Age abouttwo million years ago.Natural materials: stone, wood, clay, skins, etc.

The Stone Age ended about 5000 years ago withintroduction of Bronze in the Far East. Bronze is an

alloy (a metal made up of more than one element),copper + < 25% of tin + other elements.Bronze: can be hammered or cast into a variety ofshapes, can be made harder by alloying, corrode onlyslowly after a surface oxide film forms.

The Iron Age began about 3000 years ago and continuestoday. Use of iron and steel, a stronger and cheapermaterial changed drastically daily life of a commonperson.

Age of Advanced materials: throughout the Iron Agemany new types of materials have been introduced

(ceramic, semiconductors, polymers, composites).Understanding of the relationship among structure,properties, processing, and performance of materials.Intelligent design of new materials.

Historical Perspective


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A better understanding of structure-composition-properties relations has lead to a remarkable progress

in properties of materials. Example is the dramaticprogress in the strength to density ratio of materials, thatresulted in a wide variety of new products, from dentalmaterials to tennis racquets.


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Material science is the investigation of the relationshipamong processing, structure, properties, and performance

of materials.

What is Materials Science and Engineering ?

Processing

PropertiesStructure

Observational

MaterialsOptimization Loop


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Subatomic level (Chapter 2)Electronic structure of individualatoms that defines interaction amongatoms (interatomic bonding).

Atomic level (Chapters 2 & 3)Arrangement of atoms in materials(for the same atoms can havedifferent properties, e.g. two forms ofcarbon: graphite and diamond)

Microscopic structure (Ch. 4)Arrangement of small grains ofmaterial that can be identified bymicroscopy.

Macroscopic structureStructural elements that may beviewed with the naked eye.

Structure

Monarch butt erfly~ 0.1 m


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Length-scales

Angstrom = 1 = 1/10,000,000,000 meter = 10-10 m

Nanometer = 10 nm = 1/1,000,000,000 meter = 10-9 m

Micrometer = 1m = 1/1,000,000 meter = 10-6 m

Millimeter = 1mm = 1/1,000 meter = 10-3 m

Interatomic distance ~ a few

A human hair is ~ 50 m

Elongated bumps that make up the data track on CD are~ 0.5 m wide, minimum 0.83 m long, and 125 nm high


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Length and Time Scales from the point of view of

Materials Modeling .

Mesoscopic

10-9

10-8

10-7

LengthSc

ale,meters

0.1

103

106

109

LengthScale,numberofatoms

1027

10-12

10-9

10-7

TimeScale,seconds

1

Microscopic

Mo Li, JHU, Atomisticmodel of a nanocrystalline

Dislocation DynamicsNature, 12 February, 1998

Farid Abraham, IBMMD of crack propagation

Nanoscopic

Leonid Zhigilei, UVAPhase transformation on

diamond surfaces

Eliza

bethH

olm,Sa

ndia

Intergran

ularfr

acture

Monte

CarloPot

tsmode

l


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Progressinatomic-levelunderstanding

DNA~2 nm wide

Things Nat ura l Things Manm ade

THE SCALE OF THIN GS

10 nm

Cell membrane

ATP synthaseSchematic, central core

Cat~ 0.3 m

Dust mite300 m

Monarch butt erfly~ 0.1 m

MEMS (MicroElectroMechanical Systems) Devices10 -100 m wide

Red blood cellsPollen grain

Fly ash~ 10-20 m

Bee~ 15 mm

Atoms of siliconspacing ~tenths of nm

Head of a pin1-2 mm

Magnetic domainsgarnet film

11 m wide stripes

Quantum corral of 48 iron atoms on copper surfacepositioned one at a time wit h an STM tip

Corral diameter 14 nm

Progressinminiaturizatio

n

Indium arsenidequantum dot

Quantum dot array --germanium dots on silicon

Microelectronics

Objects fashioned frommetals, ceramics, glasses, polymers ...

Human hair~ 50 m wide

Biomotor using ATP

TheMicroworld

0.1 nm

1 nanometer (nm)

0.01 m

10 nm

0.1 m100 nm

1 micrometer (m)

0.01 mm10 m

0.1 mm

100 m

1 millimeter (mm)

0.01 m

1 cm10 mm

0.1 m

100 mm

1 meter (m)100 m

10-1 m

10-2 m

10-3 m

10-4 m

10-5 m

10-6 m

10-7 m

10-8 m

10-9 m

10-10 m

Visib

le

spectrum

TheNanoworld

Self-assembledmushroom

The21stce

nturychallenge--

Fashionmaterialsatthenanoscalewithdesire

dpropertiesandfunctionality

Red blood cellswith white cell

~ 2-5 m

meter m 100 1 m

centimeter cm 10-2 0.01 m

millimeter mm 10-3 0.001 m

micrometer m 10-6 0.000001 m

nanometer nm 10-9 0.000000001 m

Chart from http://www.sc.doe.gov/production/bes/scale_of_things.html


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Properties are the way the material responds to theenvironment and external forces.

Mechanical properties response to mechanical forces,strength, etc.

Electrical and magnetic properties - response electrical

and magnetic fields, conductivity, etc.Thermal properties are related to transmission of heat andheat capacity.

Optical properties include to absorption, transmission andscattering of light.

Chemical stability in contact with the environment -corrosion resistance.

Properties


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Types of Materials

Let us classify materials according to the way the atoms are

bound together (Chapter 2).

Metals: valence electrons are detached from atoms, andspread in an 'electron sea' that "glues" the ions together.Strong, ductile, conduct electricity and heat well, are shinyif polished.

Semiconductors: the bonding is covalent (electrons areshared between atoms). Their electrical properties dependstrongly on minute proportions of contaminants. Examples:Si, Ge, GaAs.

Ceramics: atoms behave like either positive or negativeions, and are bound by Coulomb forces. They are usuallycombinations of metals or semiconductors with oxygen,nitrogen or carbon (oxides, nitrides, and carbides). Hard,brittle, insulators. Examples: glass, porcelain.

Polymers: are bound by covalent forces and also by weak

van der Waals forces, and usually based on C and H. Theydecompose at moderate temperatures (100 400 C), andare lightweight. Examples: plastics rubber.


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Several uses of steel andpressed aluminum.

Metals


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Examples of ceramic materials ranging from household to

high performance combustion engines which utilize bothmetals and ceramics.

Ceramics


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Polymers include Plastics and rubber materials

Polymers


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Polymer composite materials:reinforcing glass fibers in a

polymer matrix.

Composites


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Si wafer for computerchip devices.

Semiconductors

Micro-Electrical-Mechanical Systems(MEMS)


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Different materials exhibit different crystal structures(Chapter 3) and resultant Properties

(a) (b)

force

Material Selection


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Different materials exhibit different microstructures

(Chapter 4) and resultant Properties

Material Selection

Superplastic deformation involves low-stress sliding alonggrain boundaries, a complex process of which materialscientists have limited knowledge and that is a subject ofcurrent investigations.


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How do you decide on a specific material for yourapplication ?

Material Selection


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Composition, Bonding, Crystal Structure

and Microstructure DEFINE Materials Properties

Composition

Bonding Crystal Structure

ThermomechanicalProcessing

Microstructure


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U i it f Vi i i D t f M t i l S i d E i i

Design of materials having specific desired characteristics

directly from our knowledge of atomic structure. Miniaturization: Nanostructured" materials, withmicrostructure that has length scales between 1 and 100nanometers with unusual properties. Electroniccomponents, materials for quantum computing.

Smart materials: airplane wings that deice themselves,buildings that stabilize themselves in earthquakes

Environment-friendly materials: biodegradable orphotodegradable plastics, advances in nuclear wasteprocessing, etc.

Learning from Nature: shells and biological hard tissuecan be as strong as the most advanced laboratory-producedceramics, mollusces produce biocompatible adhesives thatwe do not know how to reproduce

Materials for lightweight batteries with high storagedensities, for turbine blades that can operate at 2500C,room-temperature superconductors? chemical sensors(artificial nose) of extremely high sensitivity, cotton shirtsthat never require ironing

Future of materials science

muffler design and analysis

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