Load Duration and Seasoning Effects on Mortise & Tennon Joinery
Load Duration and Seasoning Effects on Mortise & Tennon Joinery
Load Duration and Seasoning Effects on Mortise & Tennon Joinery
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3. Spring Theory<br />
3.1. Theory/Possible Uses<br />
Currently dowel bearing strength <str<strong>on</strong>g>and</str<strong>on</strong>g> stiffness for different species combinati<strong>on</strong>s of<br />
base <str<strong>on</strong>g>and</str<strong>on</strong>g> peg material can be found <strong>on</strong>ly by testing each base material species with the<br />
corresp<strong>on</strong>ding peg species. Obviously many tests would have to be performed in order to<br />
obtain a comprehensive table of strengths <str<strong>on</strong>g>and</str<strong>on</strong>g> stiffnesses for varying combinati<strong>on</strong>s of<br />
base <str<strong>on</strong>g>and</str<strong>on</strong>g> peg species. One possible soluti<strong>on</strong> would be to test the peg material <str<strong>on</strong>g>and</str<strong>on</strong>g> base<br />
material separately <str<strong>on</strong>g>and</str<strong>on</strong>g> then add the properties mathematically. The behavior of the<br />
combined materials is based <strong>on</strong> the theory that the two comp<strong>on</strong>ents of the joint, the base<br />
material <str<strong>on</strong>g>and</str<strong>on</strong>g> the peg, carry load as two springs in series. Figure 3-1 is a visual<br />
representati<strong>on</strong> of the spring theory.<br />
Steel<br />
Steel Rod<br />
Wood Peg<br />
+<br />
=<br />
Wood Peg<br />
Wood Base<br />
Wood Base<br />
Figure 3-1 Spring Theory C<strong>on</strong>cept from Schmidt <str<strong>on</strong>g>and</str<strong>on</strong>g> Daniels (1999)<br />
A procedure to combine the material data mathematically would reduce the need for<br />
future testing <str<strong>on</strong>g>and</str<strong>on</strong>g> make better use of the data that has already been acquired. This<br />
method of mathematically combining material properties is limited to the dowel bearing<br />
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