No, we are not required to do any physical tests on the frame materials. But
there is a small portion of the design report score that is based on
"physical testing", which differs from test driving. If you want to go the
extra mile it would be interesting to the judges if you did a few simple
tests to verify that your strength calculations and FEA analysis are valid.
Typically your material properties do not remain constant in the welded
areas, so FEA only has limited value. Heat affected zone, poor penetration,
and stress concentrations are the cause of this.
For a class project a while back I cut open some welds that looked perfectly
good on the outside (the test samples were prepared by an experienced baja
member who agrees he needs more practice before welding on the car). It was
discovered that the weld penetration was rather poor. The moral of the story
is that the experience and equipment available to many teams is the most
likely weakness in a student design. I recommend you begin your testing by
analyzing the human factor rather than second guessing the quality of
certified materials (by the human factor I mean calculations, quality of
fabrication, and driver skill)
Then again the judges may not be so objective, and I myself don't have a
very great record of impressing them, so do what you think will look best in
the report.
Even though SAE increased the strength and weight of our roll cages with the
rules changes in 2003, I wonder how many teams are driving around with 50%
weld penetration and body filler to hide the lumps.
Sorry if I hurt anyone's feelings, I just wanted to get that off my chest. I
hope my advice can help someone out.
Eric Hutchenreuther
Kettering University
----- Original Message -----
From: "Paterson S" <paters6@uwindsor.ca>
To: <mini-baja@autox.team.net>
Sent: Wednesday, December 10, 2003 1:36 PM
Subject: Material testing
> Hey guys,
>
> Just wondering if anyone knows whether or not it is
> required to physically do material testing on the steel
> tubing that we are using for our chassis, ie. tensile,
> bending and buckling tests or if we can just do an FEA
> analysis on it? I am just curious about whether or not we
> had to have actual proof of doing physical tests to our
> material to show the judges at the competition because I
> can't seem to find it anywhere in the rules stating that we
> have to and for some reason past team's have done it.
> Sorry if this is a dumb question, I just didn't know who
> else to ask.
> Thanks
>
> Sarah Paterson
> Team Manager
> Midwest Mini Baja
> University of Windsor
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