Tampere University of Technology

TUTCRIS Research Portal

A continuum damage model for creep fracture and fatigue analyses

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Details

Original languageEnglish
Title of host publication21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy
Pages 887–894
Number of pages8
DOIs
Publication statusPublished - 2016
Publication typeA4 Article in a conference publication
EventEUROPEAN CONFERENCE ON FRACTURE, FRACTURE MECHANICS FOR DURABILITY, RELIABILITY AND SAFETY -
Duration: 1 Jan 1900 → …

Publication series

NameProcedia Structural Integrity
Volume2
ISSN (Print)2452-3216

Conference

ConferenceEUROPEAN CONFERENCE ON FRACTURE, FRACTURE MECHANICS FOR DURABILITY, RELIABILITY AND SAFETY
Period1/01/00 → …

Abstract

In this paper a thermodynamically consistent formulation for creep and creep-damage modelling is given. The model is developed for isotropic solids by using proper expressions for the Helmholtz free energy and the complementary form of the dissipation potential, and can be proven to fulfill the dissipation inequality. Also the coupled energy equation is derived. Continuum damage model with scalar damage variable is used to facilitate simulations with tertiary creep phase. The complementary dissipation potential is written in terms of the thermodynamic forces dual to the dissipative variables of creep strain-rate and damage-rate. The model accounts for the multiaxial stress state and the difference in creep rupture time in shear and axial loading as well as in tensile and compressive axial stress. In addition, the model is simple and only four to eight material model parameters are required in addition to the elasticity parameters. A specific version of the proposed model is obtained when constrained to obey the Monkman-Grant relationship between the minimum creep strain-rate and the creep rupture time. The applicability of the Monkman-Grant hypothesis in the model development is discussed. The proposed 3D-model is implemented in the ANSYS finite element software by the USERMAT subroutine. Material parameters have been estimated for the 7CrMoVTiB10-10 steel (T24) for temperatures ranging from 500 to 600 degrees of celcius. Some test cases with cyclic thermal fatigue analysis are presented.

Publication forum classification

Field of science, Statistics Finland