Your Visual Library!

ANALYTICAL

FATIGUE
by Kelly
All images scanned by T. Schmierer

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Visual example of axial stress

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Visual example of torsional stress

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Visual example of flexural stress

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An S-N plot for an aluminum alloy

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A diagram showing location of the three steps in a fatigue fracture under axial stress

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A diagram showing the surface of a fatigue fracture.
The rough surface indicates brittle failure, while the smooth surface represents crack propagation

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An example of beachmarks or "clamshell pattern" associated with stress cycles that vary in magnitude and time as in factory machinery

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An example of the striations found in fatigue fracture.

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Equation 1

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Equation 2

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Equation 3

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Equation 4

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A case hardened steel gear

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Example of pits formed by corrosion on the surface of LiF



STRESS INTENSITY
by Kim
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Schematic representations of
(a) an interior crack in a plate of infinite width, and
(b) an edge crack in a in a plate of semi-infinite width

term812.gif
Schematic representation showing the effect of plate thickness on fracture toughness

term83.gif
Basic modes of loading involving different crack surface displacements

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Graph showing distribution of stresses in vicinity of crack tip

termbell.gif
Picture of the Liberty Bell



STRESS CONCENTRATION
by Noble
All images scanned by T. Schmierer

img00001.gif
Diagram showing
(a)The geometry of surface and internal cracks.
(b) Schematic stress profile along the line X-X' in (a),
demonstrating stress amplification at crack tip positions

img00002.gif
Equation 1

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Equation 2

img00004.gif
Diagrams showing stress concentration factor plots for three different macroscopic flaw situations



ENERGY METHODS
by Yue
All images scanned by M. Gallagher

img00001.gif
Diagram of a plate with a crack growing with an applied stress

img00002.gif
Fractograph of ductile cast iron showing a transgranular fracture surface

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Fractograph of an intergranular fracture surface

img00004.gif
Three modes of crack surface displacements

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A cracked body with a force (F) and (a) is the crack length

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A graph of the increase of growth rate with crack size

img00007.gif
Illustration of Charpy and Izod Impact Tests

img00008.gif
A graph of the temperature dependence on the Charpy V-notch impact energy
(curve A) and percent shear fracture (curve B)



NUMERICAL

THEORY
by Midkiff
All images scanned by J. Midkiff

midkiff1.jpg
Structure of a three-member truss

midkiff2.jpg
Single truss member

midkiff3.jpg
Equation 1

midkiff4.jpg
Equation 2

midkiff5.jpg
Force diagram of single truss member

midkiff6.jpg
Equation 3

midkiff7.jpg
Equation 4

midkiff8.jpg
Equation 5

midkiff9.jpg
Three member truss

midkif10.jpg
diagram showing displacements and external forces
on a three member truss

midkif11.jpg
Equation 6

midkif12.jpg
Equation 7

midkif13.jpg
Equation 8

midkif14.jpg
Nodal forces on a three member truss

midkif15.jpg
Equation 9

midkif16.jpg
Equation 10

midkif17.jpg
Equation 11



EXAMPLES
by Schultz
All images preprocessed in Patran and processed in
Abaqus by J. Schultz on an ESM workstation

rmin.gif
FEA results of stresses in a plate with an elliptical crack

rmed.gif
FEA results of stresses in a plate with an elliptical crack

circle.gif
FEA results of stresses in a plate with a circular crack

mesh.gif
Mesh with boundary conditions for one of the models

geom.gif
Geometry of FEA drawn in Autocad

SIMPLE COMPUTER PROBLEM
by Tingler
All images scanned by T. Schmierer

Tingler8-1.jpg
Equation 8.1

Tingler8-2.jpg
Equation 8.2

Tingler8-5.jpg
Equation 8.5 a,b,c

Tingler8-6.jpg
Equation 8.6

Tingler8-7.jpg
Equation 8.7

Tingler8-8.jpg
Equation 8.8

Tingler8-9.jpg
Equation 8.9

Tingler8-10.jpg
Equation 8.10



HISTORY/INTRODUCTION
by Widas
widas1.jpg
Figure 1 from http://www.noraneng.com

widas2.jpg
Mesh diagram of a van

widas3.jpg
Figure 3 from http://umass.edu/mie/labs/mda/fea/fealib/goldstein/PROJECT.html

widas4.jpg
Non-linear model of a bicycle frame

widas5.jpg
Fatigue analysis of a train



EXPERIMENTAL

DUCTILE FRACTURE
by Bailey
All images scanned by T. Schmierer

bailey1.jpg
A tensile stess-strain curve

bailey2.jpg
A scanning electron fractograph of ductile cast iron, examining a transgranular fracture surface

bailey3.jpg
Figure showing the macroscopic differences between two ductile specimens(a,b)
and the brittle specimen (c)

bailey4.jpg
Figure demonstrating the microscopic qualities of ductile fracture surfaces

bailey5.jpg
Figure demonstrating the microscopic qualities of ductile fracture surfaces

bailey6.jpg
Sheared aluminium specimen showing cup and cone, and brittle fracture

bailey7.jpg
Graph that determines brittle to ductile transition
through an impact test for a 1018 hot-rolled steel



BRITTLE FRACTURE
by Ballard
chevrons.gif
Chevron fracture surface

intergran.gif
Diagram showing intergranular fracture

radiate.gif
Radiating ridge fracture surface

transgran.gif
Diagram showing transgranular fracture



DESIGN
by Gordon
All images scanned by T. Schmierer

cf-1.jpg
Graph showing aluminum oxide's modulus of elasticity as a function of porosity

cf-2.jpg
Graph showingaluminum oxide's modulus of rupture as a function of porosity

cf-3.jpg
Diagram of a ceramic material before sintering

cf-4.jpg
Diagram of a ceramic material during sintering

cf-5.jpg
Diagram of a ceramic material after sintering

pe-1.jpg
Equation showing the minimum fiber length for a continuous fiber composite

pe-2.jpg
Equation showing the tensile strength of a discontinous
fiber composite with fiber length greater than lc

pe-3.jpg
Equation showing the tensile strength of a discontinous
fiber composite with fiber length less than lc

rf-1.jpg
Figure showing the tenile and compressive stress on tempered glass

se-1.jpg
Equation for factor of safety

sf-1.jpg
A poor design that will create a stree concentration

sf-2.jpg
A good design that will minimise stress concentration

te-1.jpg
Equation for the minimum thickness of material before plane strain behavior occurs

te-2.jpg
Equation for the fracture toughness of a material with a thickness less than B

te-3.jpg
Equation for the fracture toughness of a material with a thickness equal to or greater than B;
when it fractures in mode I

te-4.jpg
Equation for the critical applied stress required to cause failure in a material

te-5.jpg
Equation for the critical crack length required to cause failure in a material

tf-2.jpg
Diagram of a mode I fracture

tf-3.jpg
Diagram of a mode II fracture

tf-4.jpg
Diagram of a mode III fracture

pg-1.jpg

Graph showing composite performance in relation to stress alignment



FRACTOGRAPHY
by Halahan and Mutter
clev1.jpg
Stainless steel showing transgranular cleavage
Scanned by M. Gallagher

clev2.jpg
TiB2 showing cleavage
Scanned by M. Gallager

clev3.jpg
Ni base alloy showing cleavage
Scanned by M. Gallagher

clev4.jpg
Silicon carbide showing small cleavage
Scanned by M. Gallagher

cohesive1.jpg
Obvious decohesion
Scanned by R. Halahan

cohesive2.jpg
Stainless steel showing hydrogen embrittlement
Scanned by R. Halahan

cohesive3.jpg
Stainless steel showing decohesive rupture
Scanned by M. Gallagher

cohesive4.jpg
Carbon-Magnesium steel showing stress corrosion cracking
Scanned by M. Gallagher

cohesive5.jpg
Low carbon steel with a layer of oxide
Scanned by R. Halahan

cohesive6.jpg
Low carbon steel with a layer of oxide
Scanned by R. Halahan

fatig1.jpg
Nickel based alloy with fatigue striations
Scanned by M. Gallagher

fatig2.jpg
Enlarged picture of fatig1.jpg
Scanned by M. Gallagher

fatig3.jpg
Nickel based alloy with jagged fatigue striations
Scanned by M. Gallagher

fatig4.jpg
Titanium alloy with fatigue striations
Scanned by M. Gallagher

void1.jpg
High carbon steel with an elongated dimple
Scanned by M. Gallagher

void2.jpg
AISI 10B21 Steel with well defined microvoid coalescence
Scanned by M. Gallagher

void3.jpg
Aluminum alloy with microvoids
Scanned by M. Gallagher

void4.jpg
Titanium alloy with equiaxed and elongated dimples
Scanned by M. Gallagher

void5.jpg
Nitralloy 135 M with microvoid coalescence
Scanned by M. Gallagher



FRACTURE TOUGHNESS
by McMurtry
fig1.jpg
A specimen with an internal crack

fig2.jpg
A specimen with a through-thickness crack

fig3.jpg
A specimen with a half circle surface crack

fig4.jpg
A fracture toughness vs. thickness graph

fig5.jpg
Three modes of crack surface displacement

fig6.jpg
Two ASTM standard compact specimen of different b sizes

fig7.jpg
Graph of fracture toughness vs. temperature for different steels

fig8.jpg
A graph of fracture toughness vs. temperature for various strain rates
applied to A572 steel



EXPERIMENTAL FATIGUE
by Meyer
All images scanned by C. Meyer

IMG00001.GIF
Fracture appearances of fatigue failures in bending

IMG00002.GIF
Typical fatigue zone with identifying marks

IMG00003.GIF
Graph showing the effect of hardness on the fatigue life
of threads rolled before and after heat treatment

IMG00004.GIF
Graph of bending fatigue test results on sections from crankshafts:
endurance limit versus surface treatment

IMG00005.GIF
Typical fatigue life curve

IMG00006.GIF
Bending angle guide

IMG00007.GIF
Graph of experimental data: angle vs. cycles to failure

IMG00008.GIF
Graph of crack growth rates obtained from adjacent pairs of a vs. N data points

IMG00009.GIF
figure showing completely reversed controlled strain test and
two possible stress responses, namely cycle-dependent
hardening and softening

IMG00010.GIF
Diagram of a stable stress-strain hysteresis loop

IMG00011.GIF
Elastic, plastic, and total strain vs. Life curves

IMG00012.GIF
A tension fatigue failure of a helicopter rotor blade flapping link



MOVIES
by Luszcz and Mix

cyclic.mpgand cyclic2.mpg
Fracture of a Hercules Graphite fiber/vinyl ester matrix composite resulting from a completely reversed load
controlled fatigue test
(performed by Nikhil Verghese - Tech graduate student)

brittle.mpg
shows brittle fracture of a class 20 gray iron sample resulting from a constant strain tensile test (performed by J. Luszcz and J. Mix)

ductile.mpg
shows ductile fracture of a 4 wt% Cu in Al sample resulting from a constant strain tensile test (performed by J. Luszcz and J. Mix)

fractures.jpg
shows resulting fractures of gray iron (brittle fracture, round specimen), 4 wt% Cu in Al (ductile fracture, flat specimen), and polyethylene (extremely ductile fracture, white specimen) (taken by J. Luszcz and J. Mix)


http://www.eng.vt.edu/eng/materials/classes/MSE2094_NoteBook/97ClassProj/visual/library.html
Maintained by Benjamin Liptak
Last Updated 4/30/97