采用数字剪切散斑干涉技术的实验方法对压力容器内部缺陷进行检测，得到了内部缺陷直径深度不同试样在不同压力载荷下的相位变化包裹图及相位分布图。试验结果表明，当缺陷直径与深度之比大于9时，才能检测出缺陷。依据试验测得的相位分布图，很容易判断出有无缺陷及缺陷形状和相对大小。检测结果直观，而且还可以看出明显的缺陷分布情况，对以后的实际生产具有指导作用。依据试验得到缺陷离面位移导数分布正视图可计算出缺陷的大小，且缺陷直径实测值与实际值之间相对误差都小于15%。将数字散斑剪切干涉法应用于压力容器内部缺陷的检测，不仅为压力容器检测提供了新的检测方法，同时也拓展了数字散斑剪切干涉法实验力学的应用领域。

The inner defect detection of pressure vessels was studied via the experiment in which the digital shearograhy and phase-shifting method were used. The wrapped diagrams and unwrapping diagrams of phase change of these specimens which have different diameters and depths under the various pressures were obtained. The results show that the defect of pressure vessels are detected when the proportion of the diameter and the depth of defect is greater than 9. Based on the phase diagram, it is easily determined whether the defect exists, and the defect relative size can be qualitatively obtained. Finally, the defect size is calculated from the out-of-place displacement gradient, and both the errors of the experimental and theoretical results are less than 15%. It proves that there is feasibility and advantage of the digital shearograhy when it is used in inner defect detection of pressure vessels. This study provides a new method that can detect inner defects of pressure vessels and widen the application of the digital shearograhy.