Untitled in english

Author(s)

Fernando Francisco dos Santos

• Document type: Master's Dissertation
• Press: São Paulo. , gráficos, ilustrações, mapas.
• Institution: Universidade de São Paulo (USP). Escola Politécnica (EP/BC)
• Defense date: 2003-09-24

Examining board members

Claudio Ruggieri; Arnaldo Homobono Paes de Andrade; Celio Taniguchi

• Advisor: Claudio Ruggieri
• Field of knowledge: Engineering - Naval and Oceanic Engineering
• Indexed in: Banco de Dados Bibliográficos da USP-DEDALUS
• Location: Universidade de São Paulo. Biblioteca Central da Escola Politécnica; EPBC/FD-3517

Abstract

This study explores the capabilities of a computational cell framework in a 3-D setting to model ductile fracture behavior in tensile specimens and in damaged pipelines. The computational cell methodology provides a convenient approach for ductile crack extension suitable for large scale numerical analyses which includes a damage criterion and a microstructural length scale over which damage occurs. Laboratory testing of a high strength structural steel provides the experimental stress-strain data for round bar and circumferentially notched tensile specimens to calibrate the cell model parameters for the material. The present work applies the cell methodology using two damage criterion to describe ductile fracture in tensile specimens: (1) the Gurson-Tvergaard (GT) constitutive model for void coalescence and (2) the stress-modified, critical strain (SMCS) criterion to describe the critical deformation for the material. These damage criteria are then applied to predict ductile cracking for a pipe specimen tested under cycling bend loading. While the methodology still appears to have limited applicability to predict ductile cracking behavior in pipe specimens, the cell computational model predictions of the ductile response for the tensile specimens show excellent agreement with experimental measurements. (AU)