D. McNab

The Application of Case‐Based Reasoning to Ultrasonic Data for Use in Inspection Qualification

This paper describes the application of case‐based reasoning (CBR) to provide decision support for the NDT engineer during Inspection Qualification. A key element of this process is to present experimental evidence on the effectiveness of the inspection. A prototype for the system has been developed using a case‐base which describes the defect, the probe and response. This paper discusses the motivation for the system, the case structure, weightings, similarity measures, retrieval techniques and its design and implementation.

A Rule-Based Expert System for Automatic Error Interpretation Within Ultrasonic Flaw Model Simulators

This paper describes the development of a novel rule-based expert system application that automatically runs a set of theoretical models used to simulate test procedures for ultrasonic testing methods in nondestructive evaluation and interprets their results. Theoretical modeling is an essential tool in verifying that the test procedures are fit for their intended purpose of defect detection. Four validated models are available to simulate theoretical ultrasonic flaw modeling scenarios. Under certain conditions, the models may break down and produce warning flags indicating that results may not be considered accurate. A considerable level of expertise in the theoretical background of the models is required to interpret these flags. The expert system addresses any warning flags encountered by adjusting the original simulation parameters and rerunning the test in order to produce a valid simulation. Warning flags are addressed by a rule file, which contains formal rules developed from knowledge-elicitation sessions with suitably qualified engineers. The rule file represents the action an engineer would adopt to counter highlighted warning flags. A description of the system and rule-base design is given as well as how the system and its performance were validated

A software system for inspection qualification

In safety critical and non‐routine situations, inspection capability may need to be demonstrated by an independent process of Inspection Qualification (IQ). This process is costly and time consuming. Therefore an approach that could aid in its production would be beneficial. This paper describes the development of interactive software tools empowering the NDT engineer to design and evaluate the capability of an ultrasonic inspection within a single environment. This paper discusses the motivation for the system, the design and implementation of the tools and the benefits it will provide.

Expert System Development for Use in Theoretical Ultrasonic NDT Simulations

An Expert System is currently under development, which will assist an NDE engineer to obtain valid solutions of the ultrasonic response from a flaw, utilising one of four theoretical modelling programs. Warning flags are highlighted when the model is used in a manner which may result in invalid results. A level of expertise in the theoretical background of the models is required to interpret these flags. It is possible to develop a series of coded rules which represent the processes a suitably qualified engineer would adopt to address highlighted warning flags. These coded rules can then be embedded within an expert system. This paper describes the architecture of the expert system and how various rules are activated to address warning flags.

Automated Error Interpretation in Flaw Response Models for Ultrasonic NDT

Theoretical modelling programs are used to validate test procedures during Inspection Qualification and to aid interpretation of results. “Flags” occur when the models run outside their range of validity and warn the user of possible inaccuracies in predictions. However, in order to interpret these flags significant expertise in the theoretical background to the models is required by the user. This paper describes why these flags occur and the automated steps that can be taken to extract useful predictions when they do, thus simplifying the modelling procedure.

Interactive software tools for inspection qualification

The demonstration of ultrasonic inspection reliability through Inspection Qualification is important for non‐routine or safety critical tests. However, since Inspection Qualification is time consuming and costly, the provision of interactive software tools to aid the process offers substantial advantages. This paper describes such an interactive tool set to aid Inspection Qualification. Operating within a 3D CAD environment it consists of ray tracing, coverage map and defect/ray interaction tools. Initial ray amplitudes are also calculated and displayed, and estimation of favorable surface scanning positions determined.

Computer aided inspection qualification

Inspection Qualification under the ENIQ methodology uses a Technical Justification as a key element in assuring the performance of the inspection. It combines a mixture of physical reasoning and modeling linked to limited experimental trial data from identified worst-case defects, but the qualification process is costly and time-consuming. This paper describes an investigation into providing an integrated set of intelligent software tools to aid the process of inspection qualification.