RESEARCH ON THREE DIMENSIONAL INDUSTRIAL CT METHOD FOR NDT/E OF AEROENGINE TURBINE BLADES

摘要

Implementing the standards on aeroengine structural integrity can improve the reliability and wearability of aeroengines. Non-destructive testing and evaluation (NDT/E) has been one of the research directions of aeroengine structural integrity assessment. Three dimensional industrial X-ray computed tomography(3D-ICT) can provide the internal structure information of objects with digital images and play an important role for NDT/E of aeroengines. However, the 3D-ICT image quality of turbine blades is greatly degraded by the scatter and the beam hardening caused by the high-density materials and the irregular shape of turbine blades. In order to apply 3D-ICT to NDT/E of turbine blade, this paper made some researches to improve the image quality. Firstly the properties of scatter were analyzed and a correction method based on the dyadic wavelet transform was researched. Then the physics features of beam hardening were summarized and a correction method based on the projections was presented. Finally a wall-thickness measurement method based on CT images was developed. The measurement results were presented and the accuracy reached 0.1mm. Based on these research results, a 3D-ICT system was developed for a Chinese aeroengine company and satisfied NDT/E requirements of turbine blades.