Investigation on the Effects of Environmental and Operational Conditions (EOC) on Diffuse-Field Ultrasonic Guided-Waves in Pipes

Abstract

In spite of many favorable characteristics of guided-waves for Nondestructive Evaluation (NDE) of pipes, real-world application of these systems is still quite limited. Beside the complexities derived from multi-modal, dispersive and multi-path characteristics of guided-waves, one of the main challenges in guided-wave based NDE of pipelines is sensitivity of these systems to variations of environmental and operational conditions (EOC). This paper investigates the effects of varying EOCs on guilded-wave based NDE of pipelines. We first provide a review of the studies to date in the field of guided-wave based testing to identify research gaps for enhancing the application of these systems in pipeline NDE. To study the identified gaps, guided-wave data from a fully operational piping system, with continuously varying flow rate and temperature, is used. Time-shift and amplitude drift effects due to flow rate variations are evaluated along with those of temperature. It is observed that masking effects of flow rate for damage detection can be at least as significant as temperature effects, and that such effects become more dominant when flow rate and temperature variations co-occur.