Wave-attenuation estimation in fluid-filled steel pipes: The first longitudinal guided wave mode

Abstract

Attenuations of the first (or fundamental) longitudinal guided wave modes propagating in liquid-filled steel pipes are numerically investigated. Several filling liquids transported by the steel pipe are considered in the investigation. In the numerical modeling stage, a sink is considered for abandoning standing wave modes caused by the internal liquids; hence, the attenuation dispersion curves become simpler. From the attenuation dispersion curves, two specific attenuation values corresponding to 1 MHz and 2.68 MHz are selected; then, the concept of parametric density is introduced to predict attenuation for a certain filling material. With this concept, it is possible to approximately calculate attenuation values without a complex numerical attenuation calculation. This investigation may provide fundamental data to inspectors using ultrasonic guided-wave techniques in the petrochemical industry and in the field of water supply, two branches of the economy that are always under pressure owing to the demand of increasing productivity and that are challenged owing to stricter environmental rules, thus necessitating promising, low-cost inspection techniques.