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| 低温数字图像相关方法中的制斑技术及其相关应用 |
| Techniques of speckle fabrication and its application for low temperature digital image correlation |
| Received:February 06, 2023 Revised:March 26, 2023 |
| DOI：10.7520/1001-4888-23-025 |
| 中文关键词: 低温 数字图像相关 散斑制备 焊接 参数反演 |
| 英文关键词:low temperature digital image correlation speckle fabrication welding parametric inversion |
| 基金项目:航天702所委托项目(20224810180)；国家自然科学基金项目(No.12032013, No.11972209) |
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| 中文摘要: |
| 数字图像相关技术(Digital Image Correlation, DIC)是一种基于散斑载体的全场变形测量技术。散斑载体的制备是实现变形测量的关键，目前已有喷涂、刻蚀、转印等一系列制斑方法。低温实验测试表明，常温制斑工艺在低温下会出现脆化效应，导致载体承受大变形时易开裂和脱落，使得变形测量产生较大误差，此外测量结果也受到结霜和气流扰动等问题影响，因此迫切需要开发低温散斑制备工艺。结合相关需求，本文发展了刻蚀喷涂法和基于聚四氟乙烯(PTFE)衬底的喷涂法2种低温制斑工艺，由此制得的散斑在低温条件下具有良好的稳定性，低温验证实验中，试件直至断裂前均未发生衬底开裂和散斑脱落；使用13X分子筛干燥方法解决了低温测量中的结霜问题，减少了结霜引起的图像噪声。将开发的低温制斑工艺成功应用于焊接件的低温力学性能测试和断裂力学参数反演，常温和-180℃的拉伸实验测试结果表明，低温下材料的弹性模量呈递增趋势，应力强度因子(Stress-intensification Factor, SIF)呈递减趋势。 |
| 英文摘要: |
| Digital image correlation (DIC) is a full field deformation measurement technique based on speckle carrier. The fabrication of speckle carrier is the key to realizing deformation measurement, and there are a series of speckle fabrication methods such as spraying, etching, and transferring. The low-temperature experimental tests show that the brittleness effect occurs at low temperature, which leads to the carrier cracking and falling off easily when it is subjected to large deformation, resulting in large errors in the deformation measurement. In addition, the measurement results are also affected by frosting and airflow disturbance, so it is urgent to develop the low temperature speckle fabrication process. Combined with relevant requirements, this paper has developed two low temperature speckle making processes: the etching spraying method and the spraying method based on polytetrafluoroethylene (PTFE) substrate. The obtained speckle has good stability under low temperature conditions. In the low temperature verification experiment, the speckle carrier did not crack and fall off until the specimen broke; The 13X molecular sieve drying method was used to solve the problem of frost formation in low-temperature measurement and reduced the image noise caused by frost formation. The developed low temperature speckle fabrication process has been successfully applied to the low temperature mechanical property test and fracture mechanics parameter inversion of weldments. The tensile test results at room temperature and -180℃ show that the elastic modulus of materials increased and the stress intensity factor (SIF) decreased at low temperatures. |
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