7 Mechanical Properties Stress-Strain Modulus Notes

7/31/2019 7 Mechanical Properties Stress-Strain Modulus Notes

http://slidepdf.com/reader/full/7-mechanical-properties-stress-strain-modulus-notes 1/28

Objectives

1. Define stress & strain.2. Utilize Hooke’s Law to calculate

unknown stresses and strains.

3. Determine material parameters from a

stress-strain curve.

4. Recognize elastic and plastic

components of deformation in a

material.5. Identify the regions of behavior on a

stress-strain diagram.

Stress

Intensity of ForceStress = ____ /____

Types of Stress

Normal : load perpendicularto area

Types of Stress

a) Normal

b) Shear : load parallel to area

Types of Stress

a) Normal

b) Shear

c) Hydrostatic (uniform pressure)

Strain: Intensity of Deformation

e = ____/_____ =dl / lo

Types of Strain

Normal : deformation in thethe direction of length

Longitudinal Strain

e = u / l

Transverse Strain

e = v / l

Transverse Strain

Materials tend to expand/contractin the directions perpendicular to

the load application.

Poisson’s Ratio

= - _____________axial strain

Why Poisson’s Ratio ?

Poissons Ratio Values

= 0.5 constant volume

= 0.3 good guess for most materials

Types of Strain

Normal

Shear : deformation normal to length

Types of Strain

Normal

Dilatational (volume change)

Relating Stress and Strain

Called a “Constitutive Model”

Simple Linear Model: “Hooke’s Law”

NormalS = E e

Stress = Young’s modulus x strain

ShearHooke’s Law

Shear Modulus

G = E / [2 (1+ )]

= shear stress

G = shear modulus = shear strain

Dilatational (hydrostatic)

Hooke’s Law

K= E/3(1-2)

P = pressure

K = bulk

modulus

= V/ Vo

Real Material Behavior -Hookean to a limiting strain

-Proportional limit : Deviationfrom linear

-After PL*Linear

*Non linear

Tensile Test

Callister, Materials Science & Engineering

What is Elastic Deformation?

*Recoverable strain (elastic)

*Nonrecoverable strain (plastic)

Real Material Behavior

ElasticElastic /plastic

Plastic Elastic

Sl f R Li

Slope of Recovery Line

Unload/Reload

Callister, Materials Science & Engineering

Yield Strength from S-e Curve

Everything Together

Wh t i Vi l ti

What is Viscoelastic

Deformation?

Creep Test Viscoelasticity

Deformation TypesName Math Model Time Dependency Type

Elastic Linear/Nonlinear None Recoverable

Plastic Linear/Nonlinear None Nonrecoverable

Viscoelastic Linear/Nonlinear Strong Recoverable

Viscoplastic Nonlinear Strong Nonrecoverable

Representative Modulii

Material Modulus (psi)

Aluminum 10x10^6

Steel 30x10^6

Polycarbonate 300 x 10^3

7 Mechanical Properties Stress-Strain Modulus Notes

Documents

Transcript of 7 Mechanical Properties Stress-Strain Modulus Notes

STATE OF TENNESSEE Materials.pdf · Stress & Strain Stress-Strain Curves . Points Along the Stress-Strain Curve . Allowable Stress Design . Ultimate Stress Design . Ductile & Brittle

Chapter 12 Equilibrium and Elasticity Key contents Conditions for mechanical equilibrium Indeterminate structure Stress, strain, modulus of elasticity.

The Plane Strain Young’s Modulus in Cubic Materials · The Plane Strain Young’s Modulus in Cubic Materials 149 2 General Tensor Transformation Relations for Plane Strain Young’s

Constant stress experiment ductile elastic Constant stress (strain varies) Constant strain (stress varies)

Strain, Strain Rate, Stress-2

Normal Strain and Stress Normal Strain and Stress, Stress strain diagram, Hooke’s Law 1.

Mechanical Testing. Here’s what we’re going to learn about! Forces Newton’s 2nd Stress Strain Young’s Modulus

YIELD STRESS STRAIN YOUNG’S MODULUS · 2020. 4. 28. · STRESS STRAIN ( ) ( ) CALCULATING YOUNG’S MODULUS FIRST CALCULATE CROSS-SECTIONAL AREA OF THE TEST PIECE RADIUS Pi ( )

DESIGN OF CONCRETE STRUCTURES By Sandeep Jyani Sir · Stress strain tangent chord 0,0 Young’s modulus of elasticity of concrete is also called as Young’s modulus of Elasticity

DEPARTMENT OF SCIENCE & HUMANITIESElasticity – Stress-strain diagram and its uses - factors affecting elastic modulus and tensile strength– torsional stress and ... SC, BCC, FCC,

Basic Numerical Study about the Stochastic Advantage on ... · 𝑠𝑡 and 𝜉 are stress, strain Young’s modulus, yield strain, yield strength, hardening strain, hardening elasticity

eddy1994.weebly.com · Web viewwhen the load is removed; the non-linear region in the stress-strain curve. Young’s modulus is the slope of the stress-strain curve. A lower elastic

An Introduction to Engineering Properties of Soil and Rock · Stress-strain modulus (modulus of elasticity) and Poisson’s ratio. 2. COMPACTION CHARACTERISTICS OF SOILS. The density

Effects of Temperature and Strain Rate on the Tensile ... · Elastic modulus or Young's mod- ulus is the initial slope of the stress-strain curve. ... Unfilled Polypropylene [Ll)

Stress Strain

Shear Stress and Strain Shear Stress, Shear Strain, Shear Stress and Strain Diagram 1.

Wednesday, November 4, 1998 Chapter 8: Angular Momentum Chapter 9: Density, Stress, Strain, Young’s Modulus, shear modulus.

A Snazzy title - SRJCsrjcstaff.santarosa.edu/~yataiiya/E45/PROJECTS/guitar strings.pdf · • Modulus of elasticity (Young’s modulus) is the ratio of stress over strain. ... Stress-Strain

Nature Methods: doi:10.1038/nmeth · Supplementary Note 1: Longitudinal modulus Longitudinal modulus is defined as the ratio of uniaxial stress to uniaxial strain (Supplementary Fig.

ST. ALOYSIUS INSTITUTE OF TECHNOLOGY · Web viewThe ratio of stress and strain is constant, called modulus of elasticity or young’s modulus (E) E= Stress/strain =Constant=E=, b.