UNCONFIRMED MINUTES

OF

SAE Fatigue Design and Evaluation Committee

Structural Analysis Division

Spring 2002 Meeting, Dearborn MI

Tuesday 16April – Division Progress Meeting

Structural Analysis Division –  Mary Wickham, Chairperson.  The minutes from the October meeting were approved.  The following presentations were made:

The first presentation was: "Structural Durability Analysis of an ATV"  D. Keniray discussed the structural durability analysis of the Honda ATV frame with the objective being to correlate measured strains and make life predictions.  FEDEM simulation model was constructed. Accelerations, strains, displacements were measured during test and simulation. Right side spindles were constrained in lateral direction and the vehicle fore-aft motion was constrained via matrix control.  There were some assumptions in the model. Reasonable correlation was achieved during this preliminary work. There were some modeling issues, such as lateral and fore-aft boundary conditions, elastomer stiffness and damping, structural damping, lack of bushing data, etc.. Possible future work includes: refine existing FEDEM model, create vehicle model to replicate field testing, generate duty cycle and perform life prediction and correlate with field data.

The second presentation was: "Optimum Shape Design for Fatigue Application – Notched and Welded Components."  G. Glinka discussed a method to design the global geometry of various thin-walled structures. The method is based on the concept of Statically Admissible Discontinous Stress Fields (SADSF).  The main idea of the method is to design such a geometrical shape for given boundary conditions that results in the same equivalent stress over the entire volume of the structure. It has been shown that the approach based on the SADSF method resulted in structures with geometry having very little or no local bending stress at intersections of connecting parts. The local bending occuring in thin-wall structures is one of the reasons of decreased fatigue resistance of structures such as trusses, frames and others and eliminating this phenomenon results in increased fatigue durability without the decrease of required load capacity. Optimisation of the local geometry of weldments based on the SADSF method resulted in the decrease of the local stress peaks and extension of weldment fatigue durability without the necessity of changing the basic geometrical parameters such as the plate thickness or the overall geometry of the weldment. Basic elements of the methodology will be discussed in the paper. The application of the method will be illustrated with several design examples including the global and local geometry design obtained with the help of the SADSF method.

Structural Analysis Planning Session Results: 

I.          ATV Overall Plan:

 *           It was suggested that a better title for ATV project should be used. Virtual Prototype Durability (ATV) and Digital Prototype Durability (ATV) were heard the most. (Digital Prototype Structural Durability was used in1998).

*           The group decided that in next FD&E meeting, the majority of Tuesday’s meeting should be devoted to ATV project.

*           A publication on this project will be made and Ric Mousseau ( U. of Toledo )  is elected as the editor. 10-12 papers will be included in this publication.

*           A list of people who have worked on this project will be developed by Al Conle (Ford). These people will be contacted for giving updates on what have been done.

*           Joshua Horn (John Deere) will look into measured load data.

*           FEDEM:

-- Will continue their work.

-- Go over the model to see what need to be added to the model. This info will be passed to Al Conle for distribution.

-- Provide the current FE model to Chris Leser (MTS) for distribution.

-- Clear defined objectives are needed.

*          Ric Mousseau would like to combine his tire model (autosim) with FEDEM’s rig model to run road profile simulation. Ric is looking for some support to cover one Master student to complete this.

II.          Structural Analysis Division Activity Plan - Update

1.         Mesh refinement criterion—How to evaluate adequacy of mesh: (Michele Wegscheid, Ric Mousseau , Gary Mauritzon)

            Not much progress was made due to job change and retirement.

2.         Implement G. Glinka’s weight function and evaluate potential applications:

Mary Wickham made contact with Jerry Green (John Deere). Jerry said some work are planned this Summer. May have some results at Fall meeting 2002.

G. Glinka ( U. of Waterloo ) offered to help on this.

3, 4. and 5. have been discussed in ATV session.

6.         Check to see if MTS can run test data through MTS code for verification of data integrity:   Chris Leser presented results for 4 files yesterday. For any other files, see Chris. NCode will do similar verification.

7.         Committee to use test data with dynamic model: ( Ric Mousseau )

Ric’s group and FEDEM have done some work and presentations were made yesterday.

8.         Fatigue evaluation of aluminum sheet metal connections (Hari Agrawal):

Hari will report on this in Fall02 meeting.

9.         Fatigue of sheet metal for automotive structures (Hari Agrawal and Barry Lin):  Barry Kin will talk about this in Fall02 meeting.