陈鼎圣,刘战伟,于洋*.冰体内气泡缺陷特征的“机器视觉”无损检测方法[J].实验力学,2023,38(6):704~711 |
冰体内气泡缺陷特征的“机器视觉”无损检测方法 |
“Machine vision” nondestructive testing method for the defect characteristics of bubbles in ice |
投稿时间:2022-10-06 修订日期:2022-12-06 |
DOI:10.7520/1001-4888-22-253 |
中文关键词: 激光散射 冰体气泡 无损检测 |
英文关键词:laser scattering ice bubble nondestructive testing |
基金项目:国家自然基金项目(11772052);科技冬奥专项(2018YFF0300801) |
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中文摘要: |
内部气泡对冰的力学性能影响较大,为深入了解气泡缺陷特征,通常采用切片的方式来观察冰体内部气泡分布,但需从整个冰体中切割取样,并且观测过程会彻底破坏样品。本文基于光的散射原理,设计了可控移动片光源倾斜入射和垂直图像采集的光路系统,发展了冰中缺陷特征的高效率定量无损检测方法。实验利用气泡对光源的散射现象提升了相机对冰体中气泡的辨识度,根据片光源的移动速度和气泡散射存在时长得到垂直冰面方向上气泡的尺寸,最终实现了对冰中气泡三维位置信息的准确采集。本文首先通过对透明亚克力材料中已标定形状和三维位置气泡缺陷的实验测量,验证了方法的可行性。然后对含气泡冰体进行测量,分析得到了冰体中气泡形状、位置分布、数量以及体积分数等信息。本文实验方法为非接触式测量,不会对冰体造成破坏,因而不会对同一冰样的后续使用产生影响。本文所得结果可为冰的力学性能研究以及透明材料的无损检测提供帮助及参考。 |
英文摘要: |
The mechanical property of ice can be influenced by its bubbles inside. In order to further understand the defect characteristics of bubbles, the conventional way to detect ice bubbles is to cut the ice sample into slices. In this way, the sample preparation has to separate from the ice. This paper developed an efficient quantitative identification method based on laser scattering theory to detect ice bubbles, which included a movable slant laser sheet and a camera perpendicular to the testing sample. The laser can highlight the bubbles inside and improve measurement accuracy. Starting from refraction theorem, 3D position of the bubbles can be easily acquired by a single camera. The deep dimension was determined according to the duration of bubbles being illuminated by the laser with uniform velocity. A series of experiments on transparent PMMA (polymethyl methacrylate) with certain holes or notches were conducted to verify the feasibility of this method. The shape, distribution, quantity, and volume fraction of ice bubbles were obtained by further experiments on ice samples. This method causes no damage to ice, which ensures further experiment on the same sample. This method has application potential in the study of ice mechanical properties and the nondestructive testing field of transparent material. |
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