Simulação de comportamento mecânico de corpos de prova usados em ensaios de corrosão sob tensão

Abstract

The present work uses ANSYS software to study the three steps described in the ASTM G30. Additional studies were performed: friction coefficients influence, 3D modeling compared with the hypothesis of plane deformations (2D model), and finaly the 3 steps procedure was compared with a one step procedure also described in ASTM G30. The results found that the friction coefficient mainly increases stresses in the bending phase, also increasing the elastic recovery of the specimen. However, there was no great variation for the screwing step. The stresses in the convex region varied for each phase with values in phase 1 of 790 MPa, phase 2 of -300 MPa and in phase 3 of 273 MPa. For the concave region, the stresses for phases 1, 2 and 3 are - 580MPa, 535 MPa and - 197 MPa. It was observed that the one stage bending presents tensile stresses in the central region of the concave face of the U specimen and compressive stresses in the convex face, due to the plastic deformation located in the bending region. The load was four times greater than in the three stages sample and the narrowing was similar. The 2D model presented a similar behavior regarding the stress distribution as the 3D, but with differences in the stress values. The mechanical simulation of API 5L X70 steel bending according to ASTM G30-97 (2016) is important in order to study the stress state found in the specimen before performing a stress corrosion test.