IntroductionMAE314 SolidMechanicsY.Zhu

Slide 1 Introduction

Slide 2 Introduction

Slide 3 Introduction

http://www.youtube.com/watch?v=3mclp9QmCGs

Slide 4 Introduction

MicroElectroMechanical System (MEMS)

HP: 650 Million a year Epson and Xerox: 350

Milli

TI: 600 Million a year ADI: 120 million a year Freescale: 100 Million

Million

Accelerometer(A l D i )

Digital Light Processors (DLP)(T I t t )

Ink Jet Nozzle(HP)(Analog Devices) (Texas Instruments) (HP)

Slide 5 Introduction

Digital Micro Mirror

Slide 6 Introductionhttp://www.ti.com/corp/docs/landing/dlp/index.htmhttp://www.ti.com/corp/docs/landing/dlp/index.htm

NanoElectroMechanical System (NEMS)

10 m

Chris Chen, UPenn Christoph Gerber, Science (2000)

Slide 7 Introduction

Nanostructures

Slide 8 Introduction

ZL Wang, Georgia Tech

Quiz: Statics

Assume link AC has cross-sectional area A=1/8 in2 and load P is equal to 120 lbs. What is the internal force in link AC?

Slide 9 Introduction

Procedure0a. Given/Wanted + Sketch0b. Plan Coordinate System Free Body Diagram Equilibrium Equations (Statics) Count number of unknowns and equations

S l ti Solution Check your solution !!N tNote: Use variables instead of numbers Units!

Slide 10 Stress and Strain

Units!

Normal Stress

Methods of statics allow us to determine forces and moments in a structure, but how do we determine if a load can be safely supported?

Factors: material, size, etc. Need a new concept.Stress

F=A

=

Slide 11 Introduction

Normal Strain

Normal strain () is defined as the deformation per unit length of a member under axial loading.

Normal strain is dimensionless but can be expressed inL =

Normal strain is dimensionless but can be expressed in several ways. Lets say L = 100 mm and = 0.01 mm. = 0.01 mm / 100 mm = 1 x 10-4 or 100 x 10-6

= 100 (read as 100 microstrain) = 1 x 10-4 in/in (if using English units) = 1 x 10-4 * 100 = 0.01%

Slide 12 Introduction

Stress Strain Curve

( )(MPa)

Ceramic

Steel Rubber

Slide 13 Introduction

World Trade Center Tragedy

MEMS devices

Slide 14 Introduction

Professor Z.P. Bazant, Northwestern University

Slide 15 Introduction