CAD model-based inspection and visualisation for 3D non-destructive testing of complex aerostructures

When performing non-destructive testing of aerostructures with complex geometrical shapes and curved surfaces, two problems arise: one is generation of an appropriate sequence of 3D coordinates and orientations for the inspection probe to follow complex component contours; the other is interpretation and characterιsation of defects based on 2D NDT images. By utilising the information from CAD models, this paper presents a 3D NDT software package to aid planning of NDT data acquisition via 3D simulation, and to aid defect visualisation and measurement in 3D by superimposing 2D NDT images on their 3D CAD models. The particular noteworthy and unique characteristics of the software are (a) a versatile 3D CAD model editing tool for extraction of CAD features and construction of simplified CAD models; (b) 3D scanning simulation for automatic generation of probe coordinates and orientations with respect to curved component surfaces; (c) tools for aligning and projecting a 3D CAD model on to its 2D NDT image; and (d) texture mapping to project a NDT image on to its 3D CAD model surface. Using real aircraft components with their radiographic, ultrasonic and thermographic images as examples, the software is shown to offer a unique, versatile and powerful CAD-based 3D NDT environment for fast and reliable structure integrity assessment of complex aerostructures.