| Budget Amount *help |
¥26,000,000 (Direct Cost: ¥20,000,000、Indirect Cost: ¥6,000,000)
Fiscal Year 2014: ¥14,300,000 (Direct Cost: ¥11,000,000、Indirect Cost: ¥3,300,000)
Fiscal Year 2013: ¥5,070,000 (Direct Cost: ¥3,900,000、Indirect Cost: ¥1,170,000)
Fiscal Year 2012: ¥6,630,000 (Direct Cost: ¥5,100,000、Indirect Cost: ¥1,530,000)
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| Outline of Final Research Achievements |
As a method of accurately measuring closed cracks, nonlinear ultrasonic imaging method was developed by combining the phased array and local cooling. First, we succeeded in significantly enhancing the closed-crack opening ability by global preheating and local cooling (GPLC). As the measurement system, we designed and made transducer and phased array apparatus. By applying it to closed cracks in aluminum alloy and stainless steel specimens, which are widely used in infrastructure, we demonstrated that GPLC is very useful in measuring closed cracks. Furthermore, by formulating one-dimensional heat-transfer and thermal stress analyses, we proposed a crack closure stress estimation method and demonstrated it in closed crack specimens.
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