A NUMERICAL MODEL OF MACRO-VISCOUS FAILURE OF MODERN STEELS OF GAS MAINS

Abstract

The paper discusses computer modeling of an extensive crack propagating in a gas pipeline, which (the modeling) plays an important role in determining resistivity of pipe steels to various types of failure. A modified local Gurson-Tvergaard- Niedelman (GTNm) model is presented which makes it possible to describe straight and oblique cuts, as well as a combination thereof, in viscous failure of small-size objects (bars, plates, shells). Details of the implementation of the GTNm model in the parallel FE computer program DANKO (developed in Russian Federal Nuclear Center - All-Russian Research Institute of Experimental Physics) are given. Parameters of the GTNm model have been determined based on laboratory experiments with specimens of a pipe steel of the K65 strength class. Numerical examples are given, demonstrating “working efficiency” of the GTNm model. The results are designed for numerically studying deformation, failure of specimens during tests, dynamic crack propagation in a pipeline.

Keywords: steels of gas mains, small-dimension objects, viscous failure, oblique cuts, computer modeling, finite element method, modified local Gurson − Tvergaard − Niedelman (GTNm) model.