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SAE-RLDA Division Progress Meeting:

Minutes for 17 October 1995

PREVIOUS MINUTES
Previous minutes from LaConner did not include material from Ric Mousseau's multibody dynamics presentation. This information was returned to Ric in hopes that it could be scanned and posted on the FD&E web site.

RAINFLOW STANDARD FILE FORMAT
Al Conle pointed out that the Rainflow standard has been modified to include number types needed to handle half cycle counts and data storage issues. The Proposed standard is now posted on the FD&E web site for review by anyone interested. Comments and concerns should be forwarded to D. Morrow (DanM(at)manta.iac.net).

TIME HISTORY FILE FORMATS
Dan is still waiting for a clean (i.e. not stamped Proprietary Data) copy of the MTS RPC3 format to send out. Dan expects to send out copies of this format before the next meeting for review.

MULTIBODY DYNAMICS
Ric Mousseau presented some of the current issues being addressed by the multibody dynamics modeling project.

The test stand was identified as having natural frequencies too low (11 to 17 Hz) which would be in the frequency range of interest for their studies. An ABAQUS model was used to redesign the stand to raise the natural frequencies to 34 Hz by using stiffening tubes off the back and side. The test stand is being reinforced by Tacom.

Several different bushing types are being manufactured to look at the effect of bushings on suspension response

MDI is converting models from DAD's to ADAMS.

STATISTICS
Charlie Sieck was not present but Dan Lingenfelser said there was good response to Charlie's memo sent out to identify people interested in working on statistical characterization of loads.
PRESENTATIONS
Volker Kottgen presented "Load Analysis and Synthesis for Nonproportional Loading" which described multiaxial fatigue analysis tools designed to handle nonproportional loading events. Darrell Socie presented "Multiaxial Spectrum Editing."

Minutes for 18 October 1996

In attendance: D. Morrow, A. Conle, K. Donaldson, R. Thompson, J. Hakala, R. Mousseau, S. Downing, D. Socie, H. Agrawal, R. Thakkar, B. Singh, A.K. Khosrovaneh, M. Barkely, Z. Bai, M. Lidberg, M. Sharp, H. Lamba, V. Kottgen, P. Sunness

RAINFLOW DATA FORMAT
Rainflow data format is still in the process of being approved.

TIME HISTORY DATA FILE FORMATS

Nothing has been sent out yet. Kelly promised to get a clean definition for RPCIII. Leese had mentioned at the LaConner meeting that they are using SDRC Universal files. Morrow suggested that the committee should look at what makes sense for the intended usage. RPC. . .simulation. . .fatigue analysis. . .etc. all have an effect on what is important in the time history, but maybe there is a "standard" that would work for all cases.

Socie asks "Why do this?" and suggests that any standard written would become a "documentation" standard and not a standard of how to store time histories; we would not be able to enforce a time history standard. Conle suggested a "non standard" be made available electronically in peoples' favorite file format for documentation purposes to encourage conversion tools to be written. Bai would like a uniform definition, single TH file format to eliminate extra conversion steps. Downing claimed that you could never have a "single" TH format since there is already too much ingrained special purpose usage of certain formats.

Kottgen suggests that if the objective is to exchange data then it would be useful to have one exchange standard as well as have all internal formats. If different exchange standards exist, this is now multiplied by the number of internal standards, if you want to write interfaces. . .keep the number of exchange standards down. Conle agreed that this is a good objective but suggests that if he makes available the log skidder history, it will be made available in his own format, which is weird enough that you may not be able to translate it into anything. Morrow points out that this is where this all started, namely from trying to be able to share or post data from various providers without having to to get their help each time to convert the proprietary formats.

Donaldson suggests that we send out the two formats that we have (RPCIII and SoMat's ) and let people respond and have them tell us what will and what won't work, just to get things going.

We finished this topic with the action item to try and get at least these two standards out for review by next meeting.

MULTIBODY DYNAMICS

Mousseau presented more details on the current issues being addressed by the multibody dynamics modeling project. As presented earlier, the test stand was identified as having natural frequencies too low (11 to 17 Hz), which would be in the frequency range of interest for their studies. An ABAQUS model was used to redesign the stand to raise the natural frequencies to 34 Hz by using stiffening tubes off the back and side. The test stand is being reinforced by Tacom. Several different bushing types are being manufactured to look at the effect of bushings on suspension response. MDI is converting models from DAD's to ADAMS to allow more people to participate in the modeling. Steve Haeg is instrumenting the control arms to measure loads at the reaction points, bushings, ball joints, etc. MTS will help characterize the bushings. Mousseau will contact Monroe to see if they will help characterize the shocks. They are going to run some base ine tests and are looking for suggestions for baseline runs.

STATISTICS IN ROAD LOAD DATA
Malcolm Sharp presented a short talk on statistical variance of proving ground data and engaged the committee in some discussion about what was significant, reproducible and meaningful in terms of road load variability.

SoMat is in the process of instrumenting an ATV for suspension loads and will make this available for experimentation in road load statistics. Talk to Socie or Downing for details measurements and availability.