基于CT扫描的2A12铝合金疲劳裂纹三维重建方法研究
发布时间：2018-10-17 14:00
【摘要】：对中心处含圆形缺口的2A12铝合金圆柱形试样进行复杂应力状态下的低周疲劳试验,总结出材料裂纹萌生及扩展机制。试验结果表明,复杂应力条件下2A12铝合金材料只有在疲劳循环较大时,由于第二相粒子与基体脱粘形成疲劳短裂纹。裂纹扩展过程中,沿着晶粒某一滑移系统滑动并且形成锯齿形状的晶体学裂纹路径。为了获得准确的裂纹三维形态及尺寸信息,采用计算机断层扫描(Computed tomography,CT)技术对试验件进行扫描,并对其断层图像进行对比度增强、离群滤噪等图像处理。从图像处理效果来看,离群滤噪方法对于试件结构较为简单,而内部裂纹信息分布相对连续的断层图像处理效果较为理想,且可通过调整其滤噪半径来获得更为清晰的裂纹图像。采用Matlab软件对处理后的断层图像进行三维重建,获得了裂纹的三维可视化图像及其尺寸信息,与裂纹实际情况吻合良好。
[Abstract]:The low cycle fatigue tests of cylindrical 2A12 aluminum alloy specimens with circular notches at the center were carried out under complex stress conditions. The mechanism of crack initiation and propagation was summarized. The experimental results show that the short fatigue crack of 2A12 aluminum alloy is formed only when the fatigue cycle is large under complex stress conditions due to the debonding of the second phase particles and the matrix. In the process of crack growth, a crystallographic crack path is formed by sliding along a slip system of the grain and forming a sawtooth shape. In order to obtain accurate 3D shape and size information of crack, the computer tomography (Computed tomography,CT) technique was used to scan the specimen, and the contrast of the image was enhanced and outliers were filtered. From the view of image processing effect, the outlier noise filtering method is relatively simple for the structure of the specimen, while the image processing effect of the fault image with relatively continuous distribution of internal crack information is relatively ideal. Moreover, a clearer crack image can be obtained by adjusting its noise filtering radius. The 3D reconstruction of the processed fault image is carried out by using Matlab software, and the 3D visualization image and its size information of the crack are obtained, which are in good agreement with the actual situation of the crack.
【作者单位】： 大连理工大学能源与动力学院;
【基金】：国家自然科学基金(51541108) 辽宁省教育厅科学研究一般(L2014028) 中央高校基本科研业务费专项资金(2342013 DUT13RC(3)052)资助项目
【分类号】：TG146.21
本文编号：2276891
[Abstract]:The low cycle fatigue tests of cylindrical 2A12 aluminum alloy specimens with circular notches at the center were carried out under complex stress conditions. The mechanism of crack initiation and propagation was summarized. The experimental results show that the short fatigue crack of 2A12 aluminum alloy is formed only when the fatigue cycle is large under complex stress conditions due to the debonding of the second phase particles and the matrix. In the process of crack growth, a crystallographic crack path is formed by sliding along a slip system of the grain and forming a sawtooth shape. In order to obtain accurate 3D shape and size information of crack, the computer tomography (Computed tomography,CT) technique was used to scan the specimen, and the contrast of the image was enhanced and outliers were filtered. From the view of image processing effect, the outlier noise filtering method is relatively simple for the structure of the specimen, while the image processing effect of the fault image with relatively continuous distribution of internal crack information is relatively ideal. Moreover, a clearer crack image can be obtained by adjusting its noise filtering radius. The 3D reconstruction of the processed fault image is carried out by using Matlab software, and the 3D visualization image and its size information of the crack are obtained, which are in good agreement with the actual situation of the crack.
【作者单位】： 大连理工大学能源与动力学院;
【基金】：国家自然科学基金(51541108) 辽宁省教育厅科学研究一般(L2014028) 中央高校基本科研业务费专项资金(2342013 DUT13RC(3)052)资助项目
【分类号】：TG146.21
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