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RE: seaint Digest for 22 Jul 1998

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Consider two plates of the same area, but different thicknesses, both
subjected to pretenseniong force P.


Q: How is the resultant clamping "force" in case (A) compared to case (B)? 

A: The same. Why? For equilibrium.    


Q: How is the clamping "stress" distribution in case (A) compared to case (B)?

A: Case (A) more stress concentration under the point load. Why? for
deformability of the plate (i.e. strain reason)



          | P                                |  P
          |                                  | 
          |                                  | 
         \|/                                \|/
 _________|________                  ________|__________
|__________________|                |                   | 
' ' ' ' ' ' ' ' ' '                 |___________________|
 ' ' ' ' ' ' ' ' '                  ' ' ' ' ' ' ' ' ' ' '
  ' ' ' ' ' ' ' '                   ' ' ' ' ' ' ' ' ' ' '
   '  ' ' ' ' ' '                   ' ' ' ' ' ' ' ' ' ' '
    ' ' ' ' ' '                     ' ' ' ' ' ' ' ' ' ' '
     ' ' ' ' '                      ' ' ' ' ' ' ' ' ' ' ' 
      ' ' ' '
       ' ' '
        ' '
        
        (A)                                   (B)

                                               

(Sorry, if the graphic is not so great!)

Majid Sarraf



At 01:42 PM 7/23/1998 -0500, you wrote:
>>As the tension load is applied to the bolt through the
>>connected parts, the bolt is not going to  get shorter (thereby relieving
>>strain) but get stretched even more.
>The bolt does stretch a little as external load is applied. But because 
>the clamped parts are much stiffer than the bolt, the change in bolt 
>strain (therefore stress) is small compared to the change in stress of 
>the clamped parts. So the load doesn't change.
>You need to consider both relative displacement *and* static equilibrium.
>
>Christopher Wright P.E.    |"They couldn't hit an elephant from
>chrisw(--nospam--at)skypoint.com        | this distance"   (last words of Gen.
>___________________________| John Sedgwick, Spotsylvania 1864)
>http://www.skypoint.com/~chrisw
>
>
>
>
>

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