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Title: Application of a Novel DCPD Adjustment Method for the J-R Curve Characterization: A study based on ORNL and ASTM Interlaboratory Results

Abstract

Material fracture toughness in the fully ductile region can be described by a J-integral vs. crack growth resistance curve (J-R curve). As a conventional J-R curve measurement method, the elastic unloading compliance (EUC) method becomes impractical for elevated temperature testing due to relaxation of the material and friction induced back-up shape of the J-R curve. One alternative solution of J-R curve testing applies the Direct Current Potential Drop (DCPD) technique for measuring crack extension. However, besides crack growth, potential drop can also be influenced by plastic deformation, crack tip blunting, etc., and uncertainties exist in the current DCPD methodology especially in differentiating potential drop due to stable crack growth and due to material deformation. Thus, using DCPD for J-R curve determination remains a challenging task. In this study, a new adjustment procedure for applying DCPD to derive the J-R curve has been developed for conventional fracture toughness specimens, including compact tension, three-point bend, and disk-shaped compact specimens. Data analysis has been performed on Oak Ridge National Laboratory (ORNL) and American Society for Testing and Materials (ASTM) interlaboratory results covering different specimen thicknesses, test temperatures, and materials, to evaluate the applicability of the new DCPD adjustment procedure for J-R curve characterization.more » After applying the newly-developed procedure, direct comparison between the DCPD method and the normalization method on the same specimens indicated close agreement for the overall J-R curves, as well as the provisional values of fracture toughness near the onset of ductile crack extension, Jq, and of tearing modulus.« less

Authors:
 [1];  [1];  [1];  [2]
  1. ORNL
  2. National Institute of Standards and Technology (NIST)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1356913
DOE Contract Number:  
AC05-00OR22725
Resource Type:
Conference
Resource Relation:
Conference: 17th International ASTM/ESIS Symposium on Fatigue and Fracture Mechanics, Toronto, Canada, 20170510, 20170512
Country of Publication:
United States
Language:
English
Subject:
J-R curve; DCPD; unloading compliance; normalization method; fracture toughness

Citation Formats

Chen, Xiang, Sokolov, Mikhail A, Nanstad, Randy K, and Lucon, Enrico. Application of a Novel DCPD Adjustment Method for the J-R Curve Characterization: A study based on ORNL and ASTM Interlaboratory Results. United States: N. p., 2017. Web.
Chen, Xiang, Sokolov, Mikhail A, Nanstad, Randy K, & Lucon, Enrico. Application of a Novel DCPD Adjustment Method for the J-R Curve Characterization: A study based on ORNL and ASTM Interlaboratory Results. United States.
Chen, Xiang, Sokolov, Mikhail A, Nanstad, Randy K, and Lucon, Enrico. Sun . "Application of a Novel DCPD Adjustment Method for the J-R Curve Characterization: A study based on ORNL and ASTM Interlaboratory Results". United States. doi:.
@article{osti_1356913,
title = {Application of a Novel DCPD Adjustment Method for the J-R Curve Characterization: A study based on ORNL and ASTM Interlaboratory Results},
author = {Chen, Xiang and Sokolov, Mikhail A and Nanstad, Randy K and Lucon, Enrico},
abstractNote = {Material fracture toughness in the fully ductile region can be described by a J-integral vs. crack growth resistance curve (J-R curve). As a conventional J-R curve measurement method, the elastic unloading compliance (EUC) method becomes impractical for elevated temperature testing due to relaxation of the material and friction induced back-up shape of the J-R curve. One alternative solution of J-R curve testing applies the Direct Current Potential Drop (DCPD) technique for measuring crack extension. However, besides crack growth, potential drop can also be influenced by plastic deformation, crack tip blunting, etc., and uncertainties exist in the current DCPD methodology especially in differentiating potential drop due to stable crack growth and due to material deformation. Thus, using DCPD for J-R curve determination remains a challenging task. In this study, a new adjustment procedure for applying DCPD to derive the J-R curve has been developed for conventional fracture toughness specimens, including compact tension, three-point bend, and disk-shaped compact specimens. Data analysis has been performed on Oak Ridge National Laboratory (ORNL) and American Society for Testing and Materials (ASTM) interlaboratory results covering different specimen thicknesses, test temperatures, and materials, to evaluate the applicability of the new DCPD adjustment procedure for J-R curve characterization. After applying the newly-developed procedure, direct comparison between the DCPD method and the normalization method on the same specimens indicated close agreement for the overall J-R curves, as well as the provisional values of fracture toughness near the onset of ductile crack extension, Jq, and of tearing modulus.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2017},
month = {Sun Jan 01 00:00:00 EST 2017}
}

Conference:
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