A Method for Preventing Crack Propagation in a Steel Gas Conduit Reinforced with Composite Overlays

This research presents a numerical simulation methodology for optimizing circular composite overlays’ dimensions and pressure characteristics with orthotropic mechanical properties, specifically, for metal conduits with temperature-dependent elastoplastic behavior. The primary objective of the proposed method is to prevent crack propagation during pressure surges from operational to critical levels. This study examines the “Beineu-Bozoy-Shymkent” steel gas conduit, examining its performance across a temperature range of −40 to +50̊C. This work builds on prior research on extended avalanche destruction in steel gas conduits and crack propagation prevention techniques. The analysis was conducted using a dynamic finite-element approach with the ANSYS-19.2/Explicit Dynamics software. Simulations of unprotected conduits revealed that increasing gas-dynamic pressure can convert a partial-depth crack into a through-crack, extending longitudinally to approximately seven times its initial length. Notably, at T = +50̊C, the developed crack length was 1.2% longer than that at T = −40̊C, highlighting the temperature sensitivity of crack progression. The modeling results indicate that crack propagation can be effectively controlled using a circular composite overlay with a thickness between 37.5% and 50% of the crack depth and a length approximately five times that of the initial crack, centered symmetrically over the crack. In addition, preliminary stress analysis indicated that limiting the overlay-induced pressure to 5% of the operational pressure effectively arrested crack growth without generating significant stress concentrations near the overlay boundaries, thereby preventing conduit integrity.