A comparison of stress triaxiality and strain distributions in notched bar geometries as determined by Bridgman expressions and finite element analysis

2018 ◽

Author(s):

Burak Can Cerik ◽

Sung-Ju Park ◽

Joonmo Choung

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Fracture Surface ◽

Ductile Fracture ◽

Stress Triaxiality ◽

Local Stress ◽

Fracture Initiation ◽

Isotropic Hardening ◽

Flow Rule ◽

Element Analysis

A Hosford-Coulomb type ductile fracture surface was developed for DH36 grade steels. The fracture experiments reported in the literature, which consist of tests with notched tensile specimens, tensile specimens with a central hole, shear specimen and disc specimens for punch specimens, were utilized in a detailed finite element analysis of each experiment to evaluate the evolution of local stress and strain fields and identify plasticity and fracture response of DH36. The developed plasticity model consists of a von Mises yield surface, an associated flow rule and a combined Swift-Voce type isotropic hardening rule. The loading paths to fracture initiation were determined in terms of stress triaxiality and normalized Lode angle parameter histories. Finally, the Hosford-Coulomb fracture surface was calibrated using the finite element analysis results and adapting a linear damage accumulation law.

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Application of a stress triaxiality dependent fracture criterion in the finite element analysis of unnotched Charpy specimens

Theoretical and Applied Fracture Mechanics ◽

10.1016/j.tafmec.2010.06.015 ◽

2010 ◽

Vol 54 (1) ◽

pp. 54-62 ◽

Cited By ~ 41

Author(s):

H.L. Yu ◽

D.Y. Jeong

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Fracture Criterion ◽

Stress Triaxiality ◽

Element Analysis ◽

The Finite Element Analysis

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Experimental and Analytical Study for Collapse Characteristics of 45 Deg Cylinder-to-Cylinder Intersections

Volume 3: Design and Analysis ◽

10.1115/pvp2014-28838 ◽

2014 ◽

Author(s):

Shunji Kataoka ◽

Takuya Sato ◽

Takuro Honda ◽

Masashi Takeda ◽

Toshiya Tanimoto

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

High Stress ◽

Stress Triaxiality ◽

Local Stress ◽

Reduction Factor ◽

Stress Concentrations ◽

Strength Reduction Factor ◽

Element Analysis ◽

Inelastic Analysis

The 45-degree laterals are widely used in pressure vessel nozzles and piping branch connections. Though the pressure design is always important for the 45-degree laterals, it is not a simple work because it has severe stress concentrations, it is difficult to weld and inspect, and there are some discrepancy between a conventional design and design by linear and nonlinear finite element analysis. In previous papers, authors studied the characteristics of both 90 degree tee and 45 degree laterals using an inelastic finite element analysis based on simplified shell element models and proposed Collapse Strength Reduction Factor (CSRF) based on an inelastic analysis were compared. In this paper, results of the burst test of 45-degree lateral and 90 degree intersection were shown. The fracture surface of 45-degree lateral was different from that of 90-degree intersection. These experimental results are compared with the inelastic finite element analysis results focusing on the local stress and strain behaviors. It was found that the magnitude of the local strain affected the burst pressure. Consideration should be given on the local failure due to excessive plastic strain under high stress triaxiality for the design of the 45-degree lateral by inelastic analysis.

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