The vibration bending fatigue life uncertainty of additively manufactured titanium (Ti) 6Al-4V specimens is studied. In this investigation, an analysis of microscopic discrepancies between ten fatigued specimens paired by stress amplitude is correlated with the bending fatigue life scatter. Through scanning electron microscope (SEM) analysis of fracture surfaces and grain structures, anomalies and distinctions such as voids and grain geometries are identified in each specimen. These data along with previously published results are used to support assessments regarding bending fatigue uncertainty. The understanding gained from this study is important for the future development of a predictive vibration bending fatigue life model.

References

1.
ASTM F2924-14
,
2014
,
Standard Specification for Additive Manufacturing Titanium-6 Aluminum-4 Vanadium with Powder Bed Fusion
,
ASTM International
,
West Conshohocken, PA
.
2.
ASTM F2971-13
,
2013
,
Standard Practice for Reporting Data for Test Specimens Prepared by Additive Manufacturing
,
ASTM International
,
West Conshohocken, PA
.
3.
ASTM F3049-14
,
2014
,
Standard Guide for Characterizing Properties of Metal Powders Used for Additive Manufacturing Processes
,
ASTM International
,
West Conshohocken, PA
.
4.
Yakinthos
,
K.
,
Missirlis
,
D.
,
Palikaras
,
A.
,
Storm
,
P.
,
Simom
,
B.
, and
Goulas
,
A.
,
2007
, “
Optimization of the Design of Recuperative Heat Exchangers in the Exhaust Nozzle of an Aero Engine
,”
Appl. Math. Model.
,
31
(
11
), pp.
2524
2541
.
5.
Sunden
,
B.
,
2013
, “Heat Exchangers and Heat Recovery Processes in Gas Turbine Systems,”
Modern Gas Turbine Systems
,
Lund University
,
Sweden
, pp.
224
246
.
6.
Traverso
,
A.
, and
Massardo
,
A.
,
2005
, “
Optimal Design of Compact Recuperators for Microturbine Application
,”
Appl. Therm. Eng.
,
25
(
14–15
), pp.
2054
2071
.
7.
Shih
,
H.-Y.
, and
Huang
,
Y.-C.
,
2009
, “
Thermal Design and Model Analysis of the swiss-Roll Recuperator for an Innovative Micro Gas Turbine
,”
Appl. Therm. Eng.
,
29
(
8–9
), pp.
1493
1499
.
8.
Engine Structural Integrity Program (ENSIP)
, MIL HDBK-1783B (USAF), 15 Feb 2002.
9.
Scott-Emuakpor
,
O.
,
George
,
T.
,
Henry
,
E.
,
Holycross
,
C.
, and
Brown
,
J.
,
2017
, “
As-Built Geometry and Surface Finish Effects on Fatigue and Tensile Properties of Laser Fused Titanium 6Al-4V
,”
ASME/Turbo Expo
,
Charlotte, NC
,
June 26–30
, ASME Paper No. GT2017-63482.
10.
Nicholas
,
T.
,
2006
,
High Cycle Fatigue: A Mechanics of Materials Perspective
,
Elsevier
,
Oxford, UK
.
11.
George
,
T.
,
Seidt
,
J.
,
Shen
,
M.-H. H.
,
Cross
,
C.
, and
Nicholas
,
T.
,
2004
, “
Development of a Novel Vibration-Based Fatigue Testing Methodology
,”
Int. J. Fatigue
,
26
, pp.
477
486
.
12.
Matissek
,
K.
,
Scott-Emuakpor
,
O.
,
George
T
,
Holycross
,
C.
,
Crowe
,
T.
, and
Howard
,
C.
,
2017
, “
Regression Study on Variables Affecting Vibration Fatigue Behavior of Additive Manufactured Titanium 6Al-4V
,”
ASME/Turbo Expo
,
Charlotte, NC
,
June 26–30
, ASME Paper No. GT2017-64049.
13.
Howard
,
C.
,
2016
, “
Investigation of Surface Roughness Effects on Material Behavior of Additive Manufactured Titanium 6Al-4V
,”
Dayton Engineering Sciences Symposium
,
Dayton, OH
,
Nov. 1
.
14.
Crowe
,
T.
,
2016
, “
Geometric Deviation and the Effect on Fatigue Life of Additive Manufactured Titanium 6Al-4V
,”
Dayton Engineering Sciences Symposium
,
Dayton, OH
,
Nov. 1
.
15.
Scott-Emuakpor
,
O.
,
George
,
T.
,
Holycross
,
C.
, and
Cross
,
C.
,
2016
, “Improved Hybrid Specimen for Vibration Bending Fatigue,”
Fatigue, Fracture, Failure and Damage Evolution
,
Vol. 8
,
A.
Zehnder
et al, eds.,
Springer
,
New York
, pp.
21
30
.
16.
Metallic Materials Properties Development and Standardization
, MMPDS-08, Battelle Memorial Institution, 1 Apr. 2013.
17.
George
,
T.
,
Shen
,
M.-H. H.
,
Cross
,
C.
, and
Nicholas
,
T.
,
2006
, “
A New Multiaxial Fatigue Testing Method for Variable Amplitude Loading and Stress Ratio
,”
ASME J. Eng. Gas Turbines Power
,
128
, pp.
857
864
.
18.
Bruns
,
J.
,
Zearley
,
A.
,
George
,
T.
,
Scott-Emuakpor
,
O.
, and
Holycross
,
C.
,
2015
, “
Vibration-Based Bending Fatigue of a Hybrid Insert-Plate System
,”
J. Exp. Mech.
,
55
(
6
), pp.
1067
1080
.
19.
Scott-Emuakpor
,
O.
,
Shen
,
M.-H. H.
,
George
,
T.
, and
Cross
,
C.
,
2008
, “
An Energy-Based Uniaxial Fatigue Life Prediction Method for Commonly Used Gas Turbine Engine Materials
,”
ASME J. Eng. Gas Turbines Power
,
130
(
6
), p.
062504
.
20.
Scott-Emuakpor
,
O.
,
Schwartz
,
J.
,
George
,
T.
,
Holycross
,
C.
,
Cross
,
C.
, and
Slater
,
J.
,
2015
, “
Bending Fatigue Life Characterization of Direct Metal Laser Sintering Nickel Alloy 718
,”
Fatigue Fract. Eng. Mater. Struct.
,
38
(
9
), pp.
1105
1117
.
21.
Bruns
,
J.
,
2014
, “
Fatigue Crack Growth Behavior of Structures Subject to Vibratory Stresses
,”
Society of Experimental Mechanics Annual Conference
,
Greenville, SC
,
June 2–6
.
22.
Scott-Emuakpor
,
O.
,
Holycross
,
C.
,
George
,
T.
,
Beck
,
J.
,
Schwartz
,
J.
,
Shen
,
M.-H. H.
, and
Slater
,
J.
,
2014
, “
Material Property Determination of Vibration Fatigued DMLS and Cold-Rolled Nickel Alloys
,”
ASME/Turbo Expo
,
Dusseldorf, Germany
,
June 16–20
, ASME Paper No. GT2014-26247.
23.
Maxwell
,
D. C.
, and
Nicholas
,
T.
,
1998
, “
A Rapid Method for Generation of a Haigh Diagram for High Cycle Fatigue
,”
J. Fatigue Fract. Mech.
,
29
, pp.
626
641
, ASTM STP 1321.
24.
Bellows
,
R.
,
Muju
,
S.
, and
Nicholas
,
T.
,
1999
, “
Validation of the Step Test Method for Generating Haigh Diagrams for Ti-6Al-4V
,”
Int. J. Fatigue
,
21
(
7
), pp.
687
697
.
25.
Scott-Emuakpor
,
O.
,
George
,
T.
,
Cross
,
C.
,
Wertz
,
J.
, and
Shen
,
M.-H. H.
,
2012
, “
A New Distortion Energy-Based Equivalent Stress for Multiaxial Fatigue Life Prediction
,”
Int. J. Non-Linear Mech.
,
47
(
3
), pp.
29
37
.
26.
Newton
,
T.
,
Melkote
,
S.
,
Watkins
,
T.
,
Trejo
,
R.
, and
Reister
,
L.
,
2009
, “
Investigation of the Effect of Process Parameters on the Formation and Characteristics of Recast Layer in Wire-EDM of Inconel 718
,”
Mater. Sci. Eng.: A
,
513–514
, pp.
208
215
.
27.
Kaszynski
,
A.
,
Beck
,
J.
, and
Brown
,
J.
,
2013
, “
Uncertainties of an Automated Optical 3D Geometry Measurement Modeling and Analysis Process for Mistuned IBR Reverse Engineering
,”
ASME/IGTI Turbo Expo
,
San Antonio, TX
, ASME Paper No. GT2013-95320.
28.
Kaszynski
,
A.
,
Beck
,
J.
, and
Brown
,
J.
,
2015
, “
Experimental Validation of a Mesh Quality Optimized Morphed Geometric Mistuning Model
,”
ASME/IGTI Turbo Expo
,
Montreal, Quebec, Canada
, ASME Paper No. GT2015-43150.
29.
Thurstone
,
L. L.
,
1947
,
Multiple Factor Analysis
,
University of Chicago Press
,
Chicago, IL
.
30.
Abdi
,
H.
,
Williams
,
L.
, and
Valentin
,
D.
,
2013
, “
Multiple Factor Analysis: Principal Component Analysis for Multitable and Multiblock Data Sets
,”
Computational Statistics
,
5
(
2
), pp.
149
179
.
31.
Henry
,
E.
,
Brown
,
J.
, and
Slater
,
J.
,
2015
, “
A Fleet Risk Prediction Methodology for Mistuned IBRs Using Geometric Mistuning Models
,”
AIAA Science and Technology Forum and Exposition
,
Orlando, FL
,
Jan. 5–9
, AIAA Paper No. AIAA 2015-1144.
32.
Ugural
,
A.
, and
Fenster
,
S.
,
2003
,
Advanced Strength and Applied Elasticity
, 4th ed.,
Prentice Hall
,
Upper Saddle River, NJ
.
33.
Shigley
,
J.
, and
Mischke
,
C.
,
1989
,
Mechanical Engineering Design
, 5th ed.,
McGraw-Hill
,
New York
.
34.
Anderson
,
T.
,
2005
,
Fracture Mechanics: Fundamentals and Applications
, 3rd ed.,
Taylor and Francis
,
Boca Raton, FL
.
35.
Pilkey
,
W.
, and
Pilkey
,
D.
,
2008
,
Peterson’s Stress Concentration Factors
, 3rd ed.,
John Wiley & Sons
,
Hoboken, NJ
.
36.
Bennett
,
J.
, and
Weinberg
,
J.
,
1954
, “
Fatigue Notch Sensitivity of Some Aluminum Alloys
,”
J. Res. Natl Bureau Stand.
,
52
(
5
), pp.
235
245
.
37.
Owolabi
,
G.
,
Okeyoyin
,
O.
,
Bamiduro
,
O.
, and
Whitworth
,
H.
,
2014
, “
Extension of a Probabilistic Mesomechanics Based Model for Fatigue Notch Factor to Titanium Alloy Components
,”
Procedia Materials Science 3, 20
th
European Conference on Fracture
, pp.
1860
1865
.
38.
Whaley
,
R.
,
1962
, “
Fatigue and Static Strength of Notched and Unnotched Aluminum-Alloy and Steel Specimens
,”
J. Exp. Mech.
,
2
(
11
), pp.
329
334
.
39.
Kahlin
,
M.
,
Ansell
,
H.
, and
Moverare
,
J.
,
2017
, “
Fatigue Behaviour of Notched Additive Manufactured Ti6Al4V With As-Built Surfaces
,”
Int. J. Fatigue
,
101
(
Part 1
), pp.
51
60
.
40.
Haritos
,
G.
,
Nicholas
,
T.
, and
Lanning
,
D.
,
1999
, “
Notch Size Effects in HCF Behavior of Ti-6Al-4V
,”
Int. J. Fatigue
,
21
(
7
), pp.
643
652
.
41.
Scott-Emuakpor
,
O.
,
Holycross
,
C.
,
George
,
T.
,
Knapp
,
K.
, and
Beck
,
J.
,
2016
, “
Fatigue and Strength Studies of Titanium 6Al-4V Fabricated by Direct Metal Laser Sintering
,”
ASME J. Eng. Gas Turbines Power
,
138
(
2
), p.
022101
.
42.
ASM Handbook
,
1996
, “
Volume 19: Fatigue and Fracture
,”
ASM International
,
Materials Park, OH
.
43.
Sangid
,
M.
,
Maier
,
H.
, and
Sehitoglu
,
H.
,
2011
, “
The Role of Grain Boundaries on Fatigue Crack Initiation—An Energy Approach
,”
Int. J. Plasticity
,
21
(
5
), pp.
801
821
.
44.
Hayes
,
B.
,
Martin
,
B.
,
Welk
,
B.
,
Kuhr
,
S.
,
Ales
,
T.
,
Brice
,
D.
,
Ghamarian
,
I.
,
Baker
,
A.
,
Haden
,
C.
,
Harlow
,
D.
,
Fraser
,
H.
, and
Collins
,
P.
,
2017
, “
Predicting Tensile Properties of Ti-6Al-4V Produced via Directed Energy Deposition
,”
Acta Mater.
,
133
, pp.
120
133
.
45.
Nalla
,
R.
,
Campbell
,
J.
, and
Ritchie
,
R.
,
2002
, “
Mixed-Mode, High-Cycle Fatigue-Crack Growth Thresholds in Ti-6Al-4V: Role of Small Cracks
,”
Int. J. Fatigue
,
24
(
10
), pp.
1047
1062
.
46.
Marcus
,
H.
, and
McEvily
,
A.
,
1999
, “On Crack Closure and Crack Tip Shielding During Fatigue Crack Growth,”
Review of Progress in Quantitative Nondestructive Evaluation
,
Vol. 18
,
D.
Thompson
, ed.,
Kluwer Academic/Plenum Publishers
,
New York
, pp.
1651
1656
.
You do not currently have access to this content.