Ultrasonic-based in-service monitoring of density for organic polymeric buried pipelines

Abstract

Non-metallic buried pipelines, particularly polyethylene (PE), are widely used in the transportation of oil and gas resources due to their low cost, corrosion resistance, and long lifespan. However, the aging of non-metallic buried pipelines is difficult to monitor in real-time during operation, which poses a significant threat to people’s life and property. Density, as an important physical property of materials, has significant potential in characterizing the aging of non-metallic materials. Nonetheless, there is little research on the density detection of curved structures based on ultrasound. Therefore, in this paper, a multi-layer heterogeneous acoustic transmission model is proposed to achieve in-service estimation of density for non-metallic buried pipelines. Building upon the transmission matrix theory, a model that is more closely aligned with the real monitoring environment was constructed, taking into account the curved surface structure of the pipeline. The model was validated through numerical simulations and experiments. The experimental results demonstrate that the model exhibits excellent performance in estimating the density of polyethylene pipelines, with an error within ±0.5 %. This study will serve as a potential powerful tool for in-service aging monitoring of non-metallic buried pipelines.