基于电子散斑干涉技术的压力容器无损检测

Nondestructive Testing of Pressure Vessels Using Electronic Speckle Pattern Interferometry

针对含有内部狭长形缺陷的球形薄壁压力容器,采用电子散斑干涉技术测试了容器表面的位移场,分析了其应变和应力场。测试结果表明,内压0.65MPa时离面位移等值线呈“花生”状,缺陷对应表面处变形产生局部凹陷,第一主应变和主应力场有明显的狭长形低值带,该低值带能反映内部缺陷的位置和形状。给出了基于板壳理论的力学分析模型,分析表明,缺陷处壳体厚度改变产生的弯矩是导致应力和应变量在缺陷处迅速降低的主要原因。

The displacement fields of one thin-wall spherical pressure vessels embedded with strip flaw were measured using electronic speckle pattern interferometry, then the strain and stress fields were analyzed. From the experimental results, the peanut-like figures appeared in the out-plane displacement contours, and local concave deformation occured in the flaw area. The obvious low-magnitude bands could be observed from the first strain and the first stress contours when the inner pressure was 0.65MPa, and the bands reflected the flaw's location and shape. Moreover, the mechanics model based on plane and shell theory was presented to explain the experimental results, and a pair of moment could be deduced due to the shell thickness change in local flaw area. Because of the moment, stress and stain components values largely decreased where local flaw occurs.