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Title: Experimental and Computational Investigations into the Effect of Process Induced Stresses on the Mode I Fracture Toughness of Composite Materials.

Abstract

Abstract not provided.

Authors:
;
Publication Date:
Research Org.:
Sandia National Lab. (SNL-CA), Livermore, CA (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1399193
Report Number(s):
SAND2016-9946C
648004
DOE Contract Number:
AC04-94AL85000
Resource Type:
Conference
Resource Relation:
Conference: Proposed for presentation at the 2016 Composites and Advanced Materials Expo (CAMX) held September 26-29, 2016 in Anaheim, CA.
Country of Publication:
United States
Language:
English

Citation Formats

Nelson, Stacy Michelle, and Werner, Brian T. Experimental and Computational Investigations into the Effect of Process Induced Stresses on the Mode I Fracture Toughness of Composite Materials.. United States: N. p., 2016. Web.
Nelson, Stacy Michelle, & Werner, Brian T. Experimental and Computational Investigations into the Effect of Process Induced Stresses on the Mode I Fracture Toughness of Composite Materials.. United States.
Nelson, Stacy Michelle, and Werner, Brian T. 2016. "Experimental and Computational Investigations into the Effect of Process Induced Stresses on the Mode I Fracture Toughness of Composite Materials.". United States. doi:. https://www.osti.gov/servlets/purl/1399193.
@article{osti_1399193,
title = {Experimental and Computational Investigations into the Effect of Process Induced Stresses on the Mode I Fracture Toughness of Composite Materials.},
author = {Nelson, Stacy Michelle and Werner, Brian T.},
abstractNote = {Abstract not provided.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2016,
month =
}

Conference:
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  • The Heavy Section Steel Technology Program (HSST) is investigating the influence of flaw depth on the fracture toughness of reactor pressure vessel (RPV) steel. Recently, it has been shown that shallow cracks tend to exhibit an elevated toughness as a result of a loss of constraint at the crack tip. The loss of constraint takes place when interaction occurs between the elastic-plastic crack-tip stress field and the specimen surface nearest the crack tip. An increased shadow-crack fracture toughness is of interest to the nuclear industry because probabilistic fracture-mechanics evaluations show that shallow flaws play a dominant role in the probabilitymore » of vessel failure during postulated pressurized-thermal-shock (PTS) conditions. The HSST investigation is a joint analytical/experimental study combining the use of shallow-cracked laboratory specimens with RPV analysis. All tests have been performed on beam specimens loaded in 3-point bending using specimens about 100 mm deep. Primarily two crack depths have been considered: a = 50 and 9 mm (a/W = 0.5 and 0.1). Test results indicate a significant increase in the fracture toughness associated with the shallow flaw specimens in the lower transition region compared to the conventional fracture toughness. The testing has produced a limited database of fracture-toughness values as a function of crack depth which can be used in probabilistic or deterministic fracture mechanics analyses of pressure vessel integrity. Final test results from the shallow-crack fracture toughness program will be included in this paper. Examination of previously tested thermal shock data reveals that no toughness elevation appears to be present even though the thermal shock cylinders were tested with shallow flaws.« less
  • The Heavy Section Steel Technology Program (HSST) is investigating the influence of flaw depth on the fracture toughness of reactor pressure vessel (RPV) steel. Recently, it has been shown that shallow cracks tend to exhibit an elevated toughness as a result of a loss of constraint at the crack tip. The loss of constraint takes place when interaction occurs between the elastic-plastic crack-tip stress field and the specimen surface nearest the crack tip. An increased shadow-crack fracture toughness is of interest to the nuclear industry because probabilistic fracture-mechanics evaluations show that shallow flaws play a dominant role in the probabilitymore » of vessel failure during postulated pressurized-thermal-shock (PTS) conditions. The HSST investigation is a joint analytical/experimental study combining the use of shallow-cracked laboratory specimens with RPV analysis. All tests have been performed on beam specimens loaded in 3-point bending using specimens about 100 mm deep. Primarily two crack depths have been considered: a = 50 and 9 mm (a/W = 0.5 and 0.1). Test results indicate a significant increase in the fracture toughness associated with the shallow flaw specimens in the lower transition region compared to the conventional fracture toughness. The testing has produced a limited database of fracture-toughness values as a function of crack depth which can be used in probabilistic or deterministic fracture mechanics analyses of pressure vessel integrity. Final test results from the shallow-crack fracture toughness program will be included in this paper. Examination of previously tested thermal shock data reveals that no toughness elevation appears to be present even though the thermal shock cylinders were tested with shallow flaws.« less
  • Ta{sub 2}O{sub 5} additions to a glass of composition 1Li{sub 2}O x 1Al{sub 2}O{sub 3} x 4SiO{sub 2} increased the hardness and decreased the indentation fracture toughness of the melt-cooled glass-ceramic. Rapid cooling discouraged agglomeration of Ta{sub 2}O{sub 5}, which enhanced precipitation hardening. Ta{sub 2}O{sub 5} was mobile in the fluid glass, allowing it to react with the Nicalon fibers to form a TaC layer which encapsulated the fibers and increased the fiber-matrix interfacial shear strength when the carbon debond layer was depleted (9% Ta{sub 2}O{sub 5} additions).