Abstract

Seven laboratories participated in an interlaboratory study to assess the applicability of ASTM E606, Test Method for Strain-Controlled Fatigue Testing, to strain-controlled fatigue of a tungsten fiber/copper matrix composite (Battelle Columbus, University of Iowa, IITRI, MCL, MarTest, Rockwell International Science Center and University of Twente). Because of the material and specimen fabrication methods, the number of fibers in the 9, 25, and 36 % fiber volume fraction specimens is approximately the same and the strain-life data are nearly identical for each of the volume fractions. Although the specimen aspect ratio is within the nominal range, the specimen diameter is less than the nominal value specified in ASTM E606. Laboratories reporting data noted that a small specimen diameter and a large gage section aspect ratio made specimen alignment difficult. Thus, specimen buckling was problematic at high strain ranges. The study data are reported and analyzed with nonparametric and semiparametric statistical methods to assess the effect of study covariates on fatigue life. The median fatigue life, median absolute deviation from the median, and interquartile range are reported as measures of central tendency and variability. ASTM E606 may be used as a guide to evaluate the fatigue response of this type of composite material if the length-to-diameter aspect ratio, specimen alignment in the fatigue machine, and specimen surface finish are closely monitored to ensure valid data.

References

1.
Winters
J.
, “
Startup Suns
,”
Mechanical Engineering
141
, no. 
1
(January
2019
):
31
35
. https://doi.org/10.1115/1.2019-JAN-1
2.
Standard Test Method for Strain-Controlled Fatigue Testing
, ASTM E606/E606M-12 (
West Conshohocken, PA
:
ASTM International
,
2012
). https://doi.org/10.1520/E0606_E0606M-12
3.
McDanels
D. L.
,
Tungsten Fiber Reinforced Copper Matrix Composites—A Review, NASA Technical Paper 2924
(
Cleveland, OH
:
National Aeronautics and Space Administration
,
1989
).
4.
Verrilli
M. J.
,
Kim
Y.-S.
, and
Gabb
T. P.
,
High Temperature Fatigue Behavior of Tungsten Copper Composites, NASA Technical Memorandum 102404
(
Cleveland, OH
:
National Aeronautics and Space Administration
,
1989
).
5.
Kim
Y.-S.
,
Verrilli
M. J.
, and
Gabb
T. P.
,
Characterization of Failure Processes in Tungsten Copper Composites under Fatigue Loading Conditions, NASA Technical Memorandum 102371
(
Cleveland, OH
:
National Aeronautics and Space Administration
,
1989
).
6.
Jerina
K. L.
and
Mitchell
M. R.
, “
A Precision Statement for Fatigue of Solid Round Wire
,”
Journal of Testing and Evaluation
47
, no. 
4
(July
2019
):
2352
2367
. https://doi.org/10.1520/JTE20180319
7.
Mitchell
M. R.
,
Meyer
M. E.
, and
Nguyen
N. Q.
,
Fatigue Considerations in Use of Aluminum Alloys, SAE Technical Paper 820699
(
Warrendale, PA
:
SAE International
,
1982
),
249
272
.
8.
Efron
B.
and
Tibshirani
R.
, “
Bootstrap Methods for Standard Errors, Confidence Intervals, and Other Measures of Statistical Accuracy
,”
Statistical Science
1
, no. 
1
(
1986
):
54
75
. https://doi.org/10.1214/ss/1177013815
9.
Cleves
M.
,
Gould
W. W.
,
Gutierrez
R. G.
, and
Marchenko
Y.
,
An Introduction to Survival Analysis Using STATA
, 2nd ed. (
College Station, TX
:
Stata Press
,
2008
).
10.
Box-Steffensmeier
J. M.
and
Jones
B. S.
, “
The Cox Proportional Hazards Model
,” in
Event History Modeling—A Guide for Social Scientists
(
Cambridge, UK
:
Cambridge University Press
,
2004
),
47
69
.
11.
Hosmer
D. W.
and
Lemeshow
S.
, “
Model Development and Assessment
,” in
Applied Survival Analysis: Regression Modeling of Time to Event Data
(
New York
:
John Wiley and Sons
,
1999
),
158
271
.
This content is only available via PDF.
You do not currently have access to this content.