Computer Simulation of Radiographic Process — A Study of Complex Component and Defect Geometry

Abstract

In proof of the applicability of a testing method, a global concept of reliability of NDE should be used which is based on both the theoretical and experimental procedure demonstration. This concept includes consequently the performance demonstration of the whole testing chain, including the physical method, the device and the inspector, by using statistical methods as well as empirical data base, and the performance prediction by computer simulation. In addition to this, the computer modeling can be used to optimise testing parameters, to make feasibility analysis for special testing problems, and to support the interpretation of indications, especially for very complicated component geometry. Thus, this variety of applications makes it necessary to develop an easy and practical model to describe the process of radiographie testing with good accuracy and with a small numerical expense, which may include any component geometry and uses experimental findings. A macroscopic model for the X-ray projection process was developed where the X-ray beam and target interaction is described as a simplified transport process. The influence of the scattering effects on the imaging process can be realised with acceptable accuracy by using a global description. The efficiency and limits of the model are discussed in terms of different examples exploring the detectability of cracks with complicated geometry. These cracks are considered for different types of high performance materials: (i) composites in the aircraft and space industry sector and (ii) realistic austenitic welding from the nuclear industry sector. These examples will show the capability of the modeling tool to handle also complicated object geometries and testing conditions like double wall penetration and ellipsoid shot.