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Publications
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SAE Fatigue Design and Evaluation Committee Meeting
Micro Minutes
October 14 & 15, 1997
Ft. Mitchell, KY (Cincinnati, OH)
Host: Dan Morrow
Disclaimer: These are not the official minutes. They are just one
individual's notes.
Dates and the location of the next meeting: March 31 & April 1 at Kansas
State, Manhattan, Kansas. Kevin Lease of Kansas State University will
host the meeting.
A working session for those involved in the new "Digital Prototype
Durability Evaluation Effort" is planned for 1:00 PM on 30 March (prior
to the main committee meeting).
Tuesday, October 14, 1997
Main Committee Meeting: Tom Cordes called the meeting to order.
Tom reminded the attendees that the SAE Administration has put a fee in
place for its service structure (in addition to the membership dues) as
follows:
$350 Committee Participation
$325 Committee Participation for Current SAE Members
$100 Mailing List Only
If this fee has not been by paid by you or your company, you have been
dropped from the mailing list, and you will not receive the meeting
mailings. The FD&E Executive Committee is concerned that this could
significantly reduce this committee's mailing list. Preliminary
indications are that the FD&E mailing list could be reduced from
approximately 300 to less then 100. Because of the devastating impact
that this would have on the committee's productivity, the FD&E Executive
Committee is going to address this issue with SAE. Call SAE if you have
any questions on how this policy affects you.
Jack Champagne, Chair of Surface Enhancement Division, reported on the
activities of the division. They are actively working on standards, and
have one (2277) out for ballot.
Each of the Division Chairmen reviewed their agenda.
John Hakula Structural Analysis
Chin-Chan Chu Fatigue Life Predication
Raj Thakkar Component Testing
Dan Morrow Road Load Data
Russ Chernenkoff Materials Properties
Jack Champaigne Surface Enhancement
Russ Chernenkoff reported that there will be a one-day session on
fatigue sponsored by FD&E at the next congress. There will be 10 papers
and Tim Topper will be the keynote speaker. In addition, Russ is
working on a book to include the 90-100 best papers presented in the
past several years.
Tom Cordes reported that AE14++ is moving forward and that all 15 papers
have been reviewed. The authors are reviewing the comments and the
papers are due back to Tom in January.
Ralph Stevens reported that the 26th annual SAE Short Course on Fatigue
was held in August and 137 attended. It will again be held in Troy MI
in August 1998.
The revised SAE Handbook on Fatigue was published.
Al Conle presented a proposal to correlate predictions to actual life
for an All Terrain Vehicle. There will be further discussion and
planning on this new longer term focus of the committee on "Digital
Prototype Durability Evaluation".
Henry Fuchs Student Travel Award Presentation: The winner of this
meeting's Henry Fuchs Award was Ning Pan of Standford University. The
title of his presentation was " The Effect of R-Ratio on the Fatigue
Response of Resistance Spot Welds".
Materials Property Division: Russ Chernenkoff chaired the Division
Meeting. The minutes from the March meeting were approved. Peter
Kurath reported that the Composites Task Group is now working on a
thermoplastic. Some material has been obtained, with 40% glass. The
first thing that they are doing is using thermo analysis to investigate
the stress in the sample. John Bonnen presented results of tests to
quantify a new threshold failure curve. The curve would represent the
curve for a minimum threshold for failure based on the strain and
plastic strain. Norm Dowling presented results of tests and a new
parameter of crack growth rates. Ralph Stevens reported on work done by
his students on powdered metal. Samples were tested that had two
densities and two sintering temperatures. Monotonic tensile strength,
plane strain fracture toughness, and fatigue behavior of smooth and
notched samples were investigated under both constant and variable
amplitude loading.
Fatigue Life Prediction Division: Chin-Chan Chu chaired the Division
Meeting. The minutes from the March meeting were approved. Sreekanth
Jallipalli made a presentation on the stress concentration factors for
tapered shafts. He used ANSYS FEA to analyze 4000 different geometries.
>From the analysis, he developed Kt 's for a wide range of L/d, r/d, and
D/d ratios. Gregory Glinka reviewed his method to analyze multiaxial
loading. He discussed the equations used in the multiaxial Neuber
approach. This strain energy density based method calculates the
stresses and strains quite well.
Component Testing Division: Raj Thakkar chaired the Division Meeting.
The minutes from the March meeting were approved. Raj Thakkar presented
some ideas/ proposed a program to investigate or link together materials
properties, structural analysis, component testing, fatigue predictions,
and road load data and simulation activities. The program could use the
ATV that has been suggested as a general project. Phil Dindinger
summarized the weld study life predictions. Eleven predictions were
submitted and predictions ranged from about half of the actual to 1,386
times greater than the actual. Steve Tipton's predictions were the
closest to the actual; his predicted lives were 1.3 to 1.2 times the
actual. Steve then presented the method(s) he used to predict the
fatigue lives. Art Cogan presented the status of his work on the
affects of surface roughness on fatigue life. He has machined some
samples measured the roughness, and residual stress. Testing is in
progress. He is going to continue his literature reviewed and is going
to try to use a FFT to analyze the surface profile.
Road Load Data Acquisition Division: Dan Morrow chaired the Division
Meeting. The minutes from the March meeting were approved. C. Lesser
presented work he is doing on analysis of various taped runs of loadings
on a car. He is looking to define the 1% driver for modeling. At this
point, he is in the early stages of the work, and basically only
outlined his objectives. Darrell Socie presented some of his
observations on the loading histories that were recorded for the ATV.
For the 14 channels of data, the main objective was to describe the
loadings in terms of load ranges. Darrell discussed how to obtain phase
information from rainflow recorded data, and how to obtain extremes in
the data.
Structural Analysis Division: John Hakula chaired the Division Meeting.
The minutes from the March meeting were approved. John announced the
new vice chairman Zhengxian Bai. A presentation was made by Zhengxian
Bai on predicting the fatigue life of spot welds. His method is based
on a structural stress analysis, and he showed that the method worked
well for several materials and with complex loads.
Surface Enhancement Division: Jack Champaigne chaired the Division
Meeting. The minutes from the March meeting were approved. Status
reports were made on five standards. Seven in process and several new
standards were discussed.
Wednesday, October 15, 1997
Technical Session
Fatigue Sensitivity Analysis of Ground Vehicle Structures - Ron
Landgraf. Ron briefly reviewed fatigue history and design tradeoffs.
He showed how one can assess different design parameters to determine
the effects of these on fatigue life and the sensitivities on fatigue
life.
Discussion on Overload Effects - Mark Pompetzki. Mark discussed
overload effects and explained how overload tests were run on the
samples in relation to John Bonnen's presentation on Tuesday.
Casting Defects and their Role on the Fatigue Behavior of Smooth and
Notched Cast AL319 - A. Dabayeh. A study was done that looked at flaws
at the notch root. A fracture mechanics based model was used. The
research was done using an optical microscope at 900X to look at the
crack tip. Using the model, the agreement between actual measurements
and analysis was good.
Modeling of Multi-axial Thermomechanical Deformation Utilizing a
Non-Unified Deformation Model - J.H. Jones. The status of his research
toward a degree was presented.
Residual Stresses in Shot Peening - Y. Jiang. The uses of shot peening
and the general effects on stresses were discussed. The presentation
included an analytical model of the stresses from peening including
relaxation effects. More work is needed for a better understanding for
an optimum design.
Peen Stress: An Analytical Pre-Peen Method to Determine the Residual
Stress Profile from Shot-Peening - J. Meister. A computer program was
demonstrated that uses an analytical model to predict the residual
stresses in a component before the part is shot-peened. The program
Peenstress has about 100 materials in the database, and several examples
were presented of predicted to x-ray diffraction measured stress values.
Divisional Planning Sessions were held concurrently in Two rooms. The
future work efforts of these five sessions will be coordinated by the
chairman and the task group leaders of the respective divisions. Please
contact the chairman with any questions or needs. Documentation of
future work planned will be included in the full minutes to be
distributed before the next meeting.
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