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It's interesting to see how it failed. Posted by RS [Email] (#15) [Profile/Gallery] (more from RS) on Mon, 25 Aug 2003 19:09:54 In Reply to: Better than while doing 70 mph, Nathan Pflaum [Profile/Gallery] , Sun, 24 Aug 2003 20:23:42 Members do not see ads below this line. - Help Keep This Site Online - Signup |
Yeah, losing it at 70 would be a serious downer.
All of the other descriptions and Dave New's pictures indicate that the cracks develop in the center leg of the C-channel section of the rear of the A-arm. Mine apparently developed the initial crack up at the the corner of the section (joint of the top and side of the c-shaped cross-section) a long time ago. That's where the rust was - everywhere else along the break, it was nice clean metal.
However, the point where the failure actually propogated from was the center of the center leg of the c-shaped cross-section. There's a classic conchoidal fracture right from the center. My guess, shooting from the hip, is that there's some residual stress from the initial welding that takes the steel over the fatigue limit when it's added with the stresses ov normal driving. If the arm were welded in such a way the that the residual stress were zero, then the A-arm wouldn't fail. That sort of explains Anders' observation. (Oh, this brings me back to my mechanics of Materials courses.)
posted by 64.63.199...
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