A hybrid DIC-EFG method for strain field characterization and stress intensity factor evaluation of a fatigue crack
A hybrid DIC-EFG method for strain field characterization and stress intensity factor evaluation of a fatigue crack
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用于疲劳裂纹应变场表征和应力强度因子评估的混合 DIC-EFG 方法
DOI：
10.1016/j.measurement.2020.107498
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发表时间：
2020
期刊：
影响因子：
5.6
通讯作者：
Jiang Lizhong
中科院分区：
文献类型：
--
作者：
Zhu Zhihui;Luo Sihui;Feng Qianshuo;Chen Yuanchang;Wang Fan;Jiang Lizhong
提出了一种结合数字图像相关（DIC）和无网格伽辽金（EFG）方法的DIC-EFG混合方法，通过计算应力强度因子（SIF）来表征裂纹的应变场和研究裂纹的断裂性能。全场位移数据由DIC测量。利用散斑图像坐标建立了无网格计算模型。然后将位移数据导入模型，用无网格法计算应变。应力强度因子是基于J积分方法得到的。为了验证该方法的准确性和稳定性，对紧凑拉伸试样（CT试样）进行了准静态循环载荷下的静态拉伸试验。该方法可以有效地预测裂纹尖端的应变，这是一个很大的挑战，DIC测量。与参考ASTM标准相比，该方法可以在不知道结构的几何形状、载荷和边界条件的情况下准确地获得结构的应力强度因子。
A Hybrid DIC–EFG Method combining Digital Image Correlation (DIC) and Element-free Galerkin (EFG) method is proposed to characterize the strain field and study the fracture performance of a crack by evaluating the stress intensity factor (SIF). The full-field displacement data is measured by DIC. The meshless calculation model is developed by using the speckle image coordinate. Then the displacement data is imported into the model and strain is calculated by the EFG method. The SIF is obtained based on theJ-integral method. A static tensile test with a quasi-static cyclic load is conducted on a Compact Tensile specimen (CT specimen) to experimentally validate the accuracy and stability of proposed method. The proposed method can effectively predict the strain at the crack tip, which is a great challenge for the DIC measurement. Compared with the reference ASTM standard, the proposed method can obtain the SIF accurately without knowing the geometry, load and boundary condition of the structure.