In order to study the static tensile strain field of 2024 aluminum alloy plate,the DIC(Digital image correlation)non-contact measurement system and the calculation software was used respectively during the whole da-mage process for image acquisition and calculation of displacement field and strain field.Deformation information was collected to optimize the speckle quality parameters and image acquisition system parameters through the orthogonal test.The optimal results of the main factors affecting the speckle quality were speckle radius of 0.02 in,speckle den-sity of 50%,speckle randomness of 69%.And the optimal results of the main factors affecting the image acquisition system were subset of 59 pixels,step of 12 pixels,angle between cameras of 20-25°,aperture of 5.6-8.Then the points along the crack were taken to study the trend of crack growth and predict the crack source and load.The in-fluence of holes with different areas and different ratios between major and minor axis on mechanical properties was studied and local strain along the radius direction was researched.Then the crack position of specimens was observed by scanning electron microscope and principle of cracking and the development of crack were explained through the analysis of strain field.Additionally,the methods of DIC,extensometers and Patran were compared.The results demonstrate that the more closer sample hole position is,the worse the strain concentration is.Reducing the sample holes area and ratio between major and minor axis can effectively decrease the strain concentration.%利用DIC(Digital image correlation)非接触全场应变测量系统分析2024铝合金板材静态拉伸应变场。对散斑质量参数、图像采集系统参数进行正交试验优化。优化结果表明,影响散斑质量的主次因素及最优结果分别为：散斑半径0.02 in,散斑密度50%,散斑分布随机性69%；影响图像采集系统的主次因素及最优结果分别为：子集大小59个像素,步长值12个像素,相机间的角度20~25°,光圈值5.6~8。采用该优化参数测量无孔及不同开孔尺寸铝合金板材静态拉伸应变场。首先,对无孔试样裂纹两侧取点,研究裂纹扩展趋势,判定裂纹源及相应载荷。其次,研究长短轴之比及开孔面积对力学性能的影响,并沿孔径方向取点,分析局部应变情况。研究表明,越靠近开孔位置,应变越集中。减小开孔面积,降低开孔的长短轴之比,可以有效降低试样的应变集中系数,延长使用寿命。最后,对比分析非接触测量方法、引伸计法及Patran建模仿真方法试验结果。
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