Re: Fixed!!! That wacky Speedo :-)

[Jim Healey <Healey@chester.lerc.nasa.gov>]

At 10:11 PM 10/7/95 EDT, you wrote:
>Hi Everybody,
>

>I've had windshields crack before,  I always thought it was drastic 
>change in temperature that did it.  But this time it was raining when I got
>back from lunch.  When I got back in after work it was still raining, but there
>was a 12-15" crack 3/4 of the way up on the drivers side post, coming down
>about a 30 degree angle.  I have no idea why it cracked.  No signs of a rock
>or anything that might have caused this.

A Long Time Ago . . . I was in an ANSYS class and one of the attendees 
worked as a consultant for GM.  It seems a certain car with an odd shaped 
rear window, could have the entire window crack by just pushing your thumb in 
the right place.  His task was to model the glass.  From what he told me
structural integrity was not high on the design list - they just wanted it
to look
good and if it breaks, let the engineers figure it out.

So are you in the habit of putting stuff on the roof or leaning on the glass?
Do you sing operatic soprano? As a side note, glass does really poorly
in tension and is quite a mismatch in the coefficient of expansion category
with aluminum (from a guy who has model several glass to metal interfaces)

jim h
>
>Anybody have any ideas ?  If there is some way to avoid this,  I'd like to save
>my $250.- deductable everytime this happens.......  This is the fourth time in
>2 cars now. :-(
>
>Mike L,
>
>
>
Jim Healey - Space Experiments Dept.
e-mail healey@lerc.nasa.gov
Aerospace Design & Fabrication, Inc.  / SETAR Team
2001 Aerospace Parkway, Brook Park, OH 44142
Desk (216) 977-1397

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