复合材料R区超声相控阵检测声场仿真试验研究

Simulation and Experimental Study on Ultrasonic Phased Array Inspection for R-Zone of Composite Material

采用常规超声检测方法进行树脂基复合材料R区结构内部缺陷检测,存在由于入射声束不能与被检测R区圆弧表面垂直而导致的检测灵敏度降低,难以实现R区整体弧度的全覆盖检测,以及不能对缺陷沿R区圆弧方向的尺寸进行评定等一系列问题。为解决上述问题,采用超声相控阵方法对R区结构进行检测,研究了相控阵检测时R区不同方向截面的声场分布规律,分析了虚拟阵元晶片数目对检测声场的影响。通过研究发现,虚拟阵元晶片数目会影响声场分布,晶片数目越多,声场分布强弱差异越大,最大声场强度越强且位置越靠近表面,6 dB声束宽度越大;聚焦检测方式下的最大声场强度普遍高于非聚焦检测方式,6 dB声束宽度小于非聚焦声场;弧形阵列不同角度虚拟探头产生声场分布基本一致,中心组晶片的最大声场强度最大。经试验验证,采用超声相控阵方法,利用圆弧阵列探头,合理设置检测参数,可以有效检出R区不同角度、不同埋深、孔径约3 mm的平底孔人工缺陷。

The conventional ultrasonic method for the R-zone of composite has a series of problems,such as reducing detection sensitivity caused by the incident sound beam not be perpendicular to the surface of the R-zone,difficulty in full coverage detection of the R-zone,and inability to evaluate the size of defects along the curvature direction of the R-zone.To solve the above issues,the ultrasonic phased array method was used to detect the R-zone of composite material,and the sound field distribution law in the R-zone was studied.The influence of the number of virtual probe on the detection sound field was analyzed.Through research,it has been found that the number of array element chips affects the sound field distribution.The more chips there are,the greater the difference in sound field distribution strength,the stronger the maximum sound field intensity,and the closer the position is to the surface,the larger the 6 dB sound beam width;Under the focusing detection method,the maximum sound field intensity is generally higher than that of the non focusing detection method,and the 6 dB sound beam width is generally smaller than that of the non focusing sound field;The distribution of sound field generated by virtual probes with different angles of arc array probes is basically consistent,and the maximum sound field intensity of the central group chip is the highest.Through experimental verification,the use of ultrasonic phased array method and the use of arc array probes with reasonable detection parameters can effectively detect artificial defects in flat bottomed holes with different angles,burial depths,and aperture of about 3 mm in the R-zone.