| 摘要 |
<p>PURPOSE: To damp vibrations at an early stage by setting the direction where a hollow penetrate as the vertical direction, and the direction orthogonal to the vertical direction as the horizontal direction in the peripheral wall of a screen-surface-forming material consisting of hollow profiles and forming a slit having a vertical component. CONSTITUTION: When a tower screen 1 receives a strong wind, a wind passed through clearances among each screen-surface forming material 4 forms a Karman vortex on the leeward side of a screen surface 2. The vortex is changed variously by the alteration of wind force while the whole is vibrated violently, and the vibrations are transmitted to the forming materials 4. A wave motion is circulated and is difficult to be damped when a cross section is formed in a closed graphic in the vibrations, but the circulation of the wave motion is inhibited at the place where the closed graphic is parted by slits 5, and the vibrations are damped at an early stage. Even when the vibrations coincide with the natural frequency of the forming materials 4 and are brought to a resonant state, the state is not extended, and is not developed up to noises. Accordingly, noises can be lowered, and structure is simplified, thus reducing an increase in cost.</p> |
