| Project/Area Number |
13650616
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Building structures/materials
|
|---|
| Research Institution | TOHOKU UNIVERSITY |
|---|
Principal Investigator |
YAMADA Motohiko Tohoku University, New Industry Creation Hatchery Center, Professor, 未来科学技術共同研究センター, 教授 (90005471)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
FUJIMOTO Katsushige Fukushima University, Department of Economics, Associate Professor, 経済学部, 助教授 (50271888)
UEMATSU Yasushi Tohoku University, Graduate School of Engineering, Associate Professor, 大学院・工学研究科, 助教授 (60151833)
|
|---|
| Project Period (FY) |
2001 – 2002
|
| Project Status |
Completed (Fiscal Year 2002)
|
| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2002: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2001: ¥2,800,000 (Direct Cost: ¥2,800,000)
|
|---|
| Keywords | steel tubular sections / hot-dip galvanized steel / non-destructive testing / high frequency ultrasonic testing / wave form analysis / evaluation of corrosion level / 腐食 / 劣化度評価 |
|---|
| Research Abstract |
The final goal of this study is to develop an evaluation system of corrosion level in the inner surface of steel tubular sections as a maintenance engineering of steel structures. As the first step of this study, the ultrasonic testing with high frequency transducers was applied to both the detection of artificial roughness in the steel plate's reverse side which was composed of uniform parallel thin grooves and the thickness measurement of hot-dip galvanized steel plates.
The correlation between the roughness and the echo was minutely examined by various conditions on both the roughness level and the ultrasonic excitation frequency. The following results were obtained;
1. The thickness in the area with roughness can be evaluated by subtracting a statistic amplitude such as Ry from the original plate thickness.
2. The wave form of ultrasonic echo varies with the pitch of groove, and the pitch of groove corresponds to the half wave length of the wave component excited by roughness.
Ultrasonic thickness measurement of hot-dip galvanized steel plates were examined and compared to two other measurements such as those using a micrometer and an electromagnetic measurement device. The following results were obtained;
1. The thickness of the hot-dip galvanized steel measured by the ultrasonic testing practically corresponds to those measured by two other methods on the assumption that the speed of longitudinal sound in the attached metal composed of Zn- and FexZny-sublayers is equal to that in the steel.
2. The surface roughness of the attached metal causes a different effect on the estimation of thickness according to the difference in the measuring method.
3. The distilled zinc ingot possesses remarkably strong acoustic anisotropy.
As the conclusion, the availability of ultrasonic testing to the evaluation of roughness in the reverse surface of steel and hot-dip galvanized steel plates has been experimentally prooved.
|
