| Budget Amount *help |
¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000)
Fiscal Year 2011: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2010: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2009: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
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| Research Abstract |
We have developed a new structural design concept for reducing sounds radiation from a plate structure. On this concept, structural intensity technique is used. The concept is based on a modal expansion of structural intensity on a plate. Using modal form of intensity, a desired power flow(distribution of intensity) can be obtained. Structural intensity in modal form can be expressed by superposition of weight coefficients and "cross-modal functions". The weight coefficients depend on an excitation point location. The cross-modal function is determined by products of two natural mode shapes with spatial derivatives and is expressed in a vector field. The cross-modal functions can be classified into two types of power flow : non energy transmission type and energy transmission type distributions. In the case of the cross-modal function having non energy transmission type distribution, the power through over the plate is zero because the integral of power flow is zero. Therefore, modal form of intensity suggests that enhancement of a non energy transmission type cross-modal function leads to less energy transmission.
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