Force and ShapeTruss
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| The Yamasen iron bridge (Double Warren truss) by Sikotu Lake in Hokkaidou Chitose City suburbs . |
The main joining part becomes a pin. |
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| Truss is used for space station Courtesy of NASDA |
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Let's attempt to make a stick into two by breaking it at the middle without using any implements.@Many people will break it like in the following photograph. Theoretically it is possible to break the stick by pulling or crushing.
But no one will do so. Many people know that breaking a toothpick into two by bending is easier.
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| By bending the stick easily breaks. (Place your mouse over the picture to see the result of bending.) |
The force only of tension or compression is added to the sticks when joining sticks with a pin and making them into triangles.
When the force (10N) is added downward to the following figurefs top, compressive force(-6.01N) works at the diagonal parts, and tensional force(3.33N) works at the bottom part.
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| Please place your mouse pointer on the figure. |
Analysis of Truss
On the truss structure, there is a transformation like a beam as a whole, but each part can be divided into the compressed part and the tensional part.
The figures below are some typical truss structures. When placing your mouse pointer on the figure, the axis power of each part when 10 N of force is loaded on the center to each truss structure appears. As for the figure, the plus shows tension and the minus shows compression. Also, as for the color, the red shows compression and the blue shows tension.
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| Warren truss |
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| Pratt truss |
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| Howe truss |
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| King post truss |
This analysis used a software program (" Analysis Truss") that is made public on the Website of Ichinose laboratory at the Nagoya Institute of Technology. The basis of structural dynamics, which contain trusses, is explained in an easy to understand way on this Website. I recommend referring to this Website to the person who wants to study structural dynamics more..
Website at Ichinose laboratory
Structual Mechanics Programs
Wright brothers learnd the truss structure to design thier airplane.