Local-Micro-Zone-Wise Time-Resolved Integrated Digital Image Correlation for Evaluating the Mechanical Properties of Welding Joints
Local-Micro-Zone-Wise Time-Resolved Integrated Digital Image Correlation for Evaluating the Mechanical Properties of Welding Joints
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DOI：
10.1007/s40799-022-00608-y
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发表时间：
2022-08
影响因子：
1.6
通讯作者：
Y. Li;J. Zhao;J. Zhou;Y. Yang;X. Huang;Z. Liu
中科院分区：
文献类型：
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作者：
Y. Li;J. Zhao;J. Zhou;Y. Yang;X. Huang;Z. Liu
焊接接头等非均质物体力学性能的综合测定在各个科学领域仍然具有挑战性。本文提出了一种局部微区时间分辨积分数字图像相关（LTIDIC）方法，该方法可以对材料的不同区域进行自划分，通过参数反演同时获得每个区域的多个弹塑性参数，包括弹性模量、屈服强度、硬化系数和硬化指数。首先，阐述了LTIDIC方法的原理和过程，介绍了自动划分区域的方法。然后，LTIDIC的可靠性进行了分析和优化，评估的相关性标准的影响，区域大小，噪声类型和图片的数量上的参数反演的结果的基础上。最后，对6061 T6铝合金薄板搅拌摩擦焊接头进行了单轴拉伸试验，并采用LTIDIC方法测量了多个力学参数的分布。结果表明，焊接区弹性模量在30 ~ 70 GPa之间，热机械影响区弹性模量最低，热影响区弹性模量最高。焊接区的屈服强度范围为75-115 MPa。弹性模量呈不对称的W形分布，塑性参数总体上呈现从熔核向两侧逐渐减小的趋势。通过与定域DIC方法的一致性比较，验证了LTIDIC方法的可行性和准确性。该方法可以通过一次拉伸实验同时获得材料不同区域的多个弹塑性参数分布，为类似焊接接头的非均质材料力学性能评价提供重要的实验数据。所发展的LTIDIC方法可以通过一次拉伸试验同时获得多个弹塑性参数分布，包括弹性模量、屈服强度、硬化系数和硬化指数.自动识别具有不同力学性能的异质材料区域。3.通过分析影响参数识别的因素，参数反演误差小于1%。它能有效地降低随机噪声对反演的影响，提高反演结果的精度。
The comprehensive determination of mechanical properties of heterogeneous objects such as welding joint remains challenging in various scientific fields. This paper develops a Local-micro-zone-wise Time-resolved Integrated Digital Image Correlation (LTIDIC) method, which can self-divide different regions of the material and get the multiple elastic–plastic parameters of each region through parameter inversion simultaneously, including elastic modulus, yield strength, hardening coefficient, and hardening exponent. First, the principle and process of the LTIDIC method are demonstrated, and the method of automatically dividing regions is introduced. Then, the reliability of the LTIDIC is analyzed and optimized, based on evaluating the influence of the correlation criteria, the area size, the noise type, and the number of pictures on the results of parameter inversion. Finally, a uniaxial tensile test was performed on the friction stir welding joint of aluminum alloy 6061T6 thin plate sample, and the distribution of multiple mechanical parameters was measured by the LTIDIC method. The results show that the modulus in the weld zone ranges between 30 and 70 GPa, with the lowest modulus in the thermo-mechanical affected zone and the highest modulus in the heat affected zone. The yield strength in the weld zone ranged from 75–115 MPa. The elastic modulus distribution shows an asymmetric W-shape, and the plastic parameters generally show a decreasing trend from the weld nugget to both sides. The feasibility and accuracy of the LTIDIC method were verified by comparing the consistency with the localized DIC method. The proposed method can obtain multiple elastic–plastic parameter distributions in different areas of material simultaneously through a single tensile experiment and provide important experimental data for the evaluation of mechanical properties of heterogeneous materials similar to welding joints.Highlights1. The developed LTIDIC method can obtain multiple elastic–plastic parameter distributions including elastic modulus, yield strength, hardening coefficient, and hardening exponent simultaneously through a single tensile experiment.2. Automatically identify areas of heterogeneous materials with different mechanical properties.3. The parameter inversion error is less than 1% by analyzing the factors that affect parameter identification. It can effectively reduce the influence of random noise on the inversion and improve the accuracy of the results.