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Smallest cross-sectional area of rod-end?

  1. Mar 2, 2008 #1
    i was doing some reading on structural mechanics and i stumbled across this example:


    i don't really get the highlighted part. anyone care to explain?


  2. jcsd
  3. Mar 2, 2008 #2


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    The pin at C exerts a force of 50kN on rod BC. In the middle of the rod, the cross section is circular, and we calculate the stress as [itex]4P/\pi d^2[/itex] (diameter d). At the end of the rod, the cross section is flattened into a rectangle, so the stress is [itex]P/wt[/itex] (width w, thickness t). BUT the width is reduced where material is cut out to fit the pin. At this cross section the stress is higher, [itex]P/(w-d)t[/itex]. Does this make sense?
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