The fir-type blade root is one of the main types of low-pressure rotor blade root. Due to the complex structure and limited detection space of the blade root

it is difficult to achieve the expected detection effect in the actual detection. In this article

ultrasonic phased-array technique was used to detect the fir-type blade roots

special blade root debugging and comparative test blocks were designed during the test

and data were collected at different positions of the blade root. Moreover

special software was used to carry out 1:1 fitting of the data atlas and structural drawings. The detection methods and effects of the ultrasonic phased-array technique was comprehensively analyzed

and it is concluded that the echo of the curved structure of the blade root will have obvious interference with the defect wave. It suggests that the placement of the probe should be paid attention to when the stress areas of different teeth of the blade root are tested

the probe should be located above the tooth and should have different displacement considerations to ensure the best detection results.