“e-NDE” stands for “electronic non-destructive evaluation.”  NDE is a common abbreviation used by quality inspectors in manufacturing industries; it stands for Non-Destructive Evaluation (e.g. x-ray radiography, ultrasonic inspection, penetrant inspection, etc.).  The “e” is added to the “NDE” abbreviation to differentiate it from standard NDE techniques.

It is an electronic inspection technique that is applied to friction stir (FS) technologies, including friction stir welding (FSW) and friction stir processing (FSP). It consists of a variety of different signal analyses approaches and techniques: 1) run sequence plots in the time domain, 2) spectral density plots in the frequency domain, 3) phase space analyses, 4) in-plane force lobe curvature analyses, 5) neural network modeling, etc.

To prepare for the analysis, force and torque feedback signals are monitored during FS processes and recorded to an electronic file.  Run sequence plots from the data files are then plotted for each feedback signal and analyzed for regularity and consistency.  If present, positions of irregularities in response signals are located and identified by positions along the weld and analyzed to mark non-uniform segments in the time series data.  Kinks, bulbs, stalls, etc., in plots of the cross force to the path force, for example, represent deviations from stable metal flow behavior as a function of time or position during FSW.

An e-NDE analysis provides information about “indications” (e.g. possible defects) and their location for subsequent inspection operations using conventional NDE methods (e.g. x-ray, ultrasonic, penetrant, etc.).  This approach augments conventional inspection operations, making them more efficient and cost effective.

Unlike standard NDE technologies, e-NDE is a green technology.  It utilizes data generated during a weld and recorded in a file.  All evaluation steps are carried out on a computer.  Inspecting joints produced by FSW, for example, with a green inspection technology like e-NDE compounds the green nature of FS technologies, which are considered green technologies because they require much less energy than standard fusion welding.