Scenarios

Scenarios introduce a set of conventions specific to a given use case, enabling a simple description of the specimen and associated probe and wedge positioning.

Many nondestructive inspection scan plans are referenced to the surface of a specimen. Scenarios corresponding to these use cases link the probe or wedge positioning through \((U,V)\) surface coordinates.

General Mapping scenario

Hypotheses:

• The probe positioning vs. the related specimen surface is constant for all \((u,v)\) position (skew angle, liftoff, etc.) or automatically compensated (i.e., adaptive acoustic, liftoff compensation, electronic).
• The \(u\) axis is the principal scan axis and is typically collinear with a physical encoder device.
• The \(v\) axis is orthogonal to the \(u\) axis and may be associated to a secondary physical encoder, an electronic scan, or both (for paint brush raster scans).
• The origin \(O\) position on the surface is arbitrarily defined by the user.

Raster example with the \(U\) and \(V\) axis.

General Weld scenario

Hypotheses:

• The scenario relates to the inspection of a single straight or curved weld or joint.
• The surface line \((u,0)\) is collinear with the center of said weld or joint.
• The probe positioning vs. the related specimen surface is constant for all \((u,v)\) position (skew angle, liftoff, etc.) or automatically compensated (i.e., adaptive acoustic, liftoff compensation, electronic).
• For pipe geometry, the orientation of the weld is defined in relation to the pipe axis. With an angle of 0° for an axial weld and 90° for a circumferential one. Any angle in between describes a helical weld.
• Scan patterns can be entirely described on the surface of specimen as a set of orthogonal axes parallel and orthogonal to the weld.

Example general weld scenario with an axial weld on a pipe.

Axial weld: The weld angle is defined in relation to the pipe axis.

Girth weld: The weld angle is defined in relation to the pipe axis.