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# RE: seaint Digest for 22 Jul 1998

• To: seaint(--nospam--at)seaint.org
• Subject: RE: seaint Digest for 22 Jul 1998
• From: Majid Sarraf <msarraf(--nospam--at)uottawa.ca>
• Date: Thu, 23 Jul 1998 19:29:49 -0400

```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
>
>
>
>
>

~      ~           ~ ___
[_________]-|__)
__________OO______O__O_O___________________________
|==========================================|
|                                          |
\               Majid Sarraf             /
\             Ph.D Candidate           /
\   Department of Civil Engineering  /
|        University of Ottawa      |
|           Ottawa, Ontario        |