Hybrid Measurement of CT and Strain Distribution of Fatigue Crack in Steel Bars Using High Energy Synchrotron Radiation Monochromatic X-Rays
Hybrid Measurement of CT and Strain Distribution of Fatigue Crack in Steel Bars Using High Energy Synchrotron Radiation Monochromatic X-Rays
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高能同步辐射单色X射线混合测量钢筋疲劳裂纹的CT和应变分布
DOI：
10.2472/jsms.58.588
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
J. Narita
中科院分区：
文献类型：
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作者：
T. Shobu;Keisuke Tanaka;A. Hashimoto;J. Narita
断裂力学已成功地应用于工程结构抗疲劳和应力腐蚀裂纹的损伤容限设计。应力强度因子是预测裂纹扩展过程的关键参数，由裂纹形状和载荷应力分布计算得到。在本研究中，使用来自同步辐射源SPring-8的能量为66.4keV的高能单色X射线，我们开发了一个系统来执行裂纹成像和裂纹周围应变分布的混合测量。将该系统应用于直径为4 mm的碳钢圆棒的疲劳裂纹。计算机断层扫描（CT）的标本给出了三维形状的拇指甲裂纹。在零应力和最大应力下，对裂纹周围的晶格应变沿加载轴沿着进行扫描。在最大应力时，裂纹前的拉应变很高，而裂纹面上的应变由于裂纹张开而很低。加载时裂纹尖端半高宽增加，卸载后又减小。卸载引起的FWHM可恢复部分是由于裂纹尖端附近的应力分布陡峭造成的。由于塑性变形引起的半高宽的增加不受卸载的影响。
Fracture mechanics have been successfully applied for damage tolerant design of engineering structures against fatigue and stress corrosion cracking. The stress intensity factor is a key parameter to predict the progress of cracking behavior, and is computed from the shape of cracks and the loading stress distribution. In the present study, using high energy monochromatic X-rays of energy 66.4keV from the synchrotron radiation source, SPring-8, we have developed a system to perform the hybrid measurement of imaging of cracks and strain distribution around cracks. This system was applied to a fatigue crack made in a round bar made of carbon steel with the diameter of 4mm. Computed tomography (CT) of the specimen gave the three-dimensional shape of a thumb-nail crack. Scanning of lattice strain along the loading axis around cracks was conducted under the zero and maximum applied stresses. High tensile strain ahead of the crack was measured at the maximum stress, while the strain on the crack face was low because of crack opening. The full width at half maximum (FWHM) increased near the crack tip under loading, and then decreased after unloading. This recoverable part of FWHM by unloading was caused by the steep distribution of the applied stress in the vicinity of the crack tip. The increase of FWHM due to plastic deformation did not change by unloading.
利用同步子辐射计算机断层扫描对铝合金疲劳裂纹进行成像
DOI：
--
发表时间：
2007
期刊：
影响因子：
--
作者：
Y. Sano;K. Masaki;K. Akita;Y. Ochi;K. Kajiwara
通讯作者：
K. Kajiwara