Total focusing imaging of wrinkle defects in carbon-fiber-reinforce-polymer composites based on wedge coupling
Wrinkles are one of the main types of defects in carbon-fiber-reinforce-polymer(CFRP)composites materials.When using ultrasonic phased array for wrinkle defects detection,blind zones phenomena are caused by interference,such as non-linear effects and electronic crosstalk in the acquisition system,which conceal the wrinkle information inside the thin plate.To reduce the impact of blind zones,an approach is proposed to add a wedge between the phased array and the composite material thin plate(less than 10 mm),and a shortest path ray tracing total focusing method coupled with the wedge is presented.Based on Fermat's principle and Snell's law,a multi-layered medium ultrasonic wave propagation model with the wedge is established.CFRP material samples with wrinkle defects are prepared,and a phased array ultrasonic data acquisition system is constructed to collect full matrix data.The imaging effects of the shortest path ray tracing total focusing method coupled with the wedge and traditional total focusing method are compared.The results indicate that the shortest path ray tracing total focusing method coupled with the wedge can reduce the depth of the blind zones on the surface of the specimen,correct the acoustic time deviation,and weaken the impact of blind zones,and restore the wrinkle defects inside the sample.Compared to the traditional total focusing method,the accuracy of the three parameters characterizing fiber wrinkles,including wrinkle length,wrinkle top height,and wrinkle angle,is improved by 5.9%,4.1%,and 4.2%,respectively.This paper provides a new approach for the detection of wrinkle defects in CFRP material thin plates.
万方数据
维普
