Acoustic Energy Mapping Method for Acousto-Optical Non-destructive Testing System with Automated Positioning

Problem statement: Most acoustic non-destructive pipeline testing methods operate according to one of two basic principles. The first one assumes passive long section monitoring using distributed sensors, while the second one relies on small region testing using piezoelectric transducers. However, there is another option which is to perform medium Section (0.5 to 200 m long) diagnostics by applying echo testing method using sensor arrays, distributed or quasi-distributed sensors. Even further functioning improvement can be achieved by acoustic components positioning automation implemented with SEMS modules. One of the main problems with this approach is the complexity of reconstruction and visualization of spatial information about defects locations. Purpose of research: Formation of the acoustic energy mapping method for the intelligent acousto-optical non-destructive pipeline testing system with automated positioning that allows echo-signal source map visualization to reveal locations of defects and inhomogeneities. Results: The work proposes an architecture for the pipeline testing system with sensors and emitters installed on a SEMS-based pipe crawler robot. It uses magnetic chassis for movement and verifies current position using rangefinder data. The paper presents a computer model that simulates sound propagation through the metal pipe material inside an area with a size of 500 × 500 mm. The model adds defects with size 0.5 to 50 mm of various shapes to random locations. Then it applies the acoustic energy mapping method that performs defect location visualization. During modelling the method skipped about ~3.6% defects. The defect location measurement error (computed as object centroid displacement) did not exceed 5.2 mm. Practical significance: The results of the work form the technical and algorithmic basis for pipeline testing systems of a new class designed for a medium-length pipeline section diagnostics.