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in subjects: "Fracture Mechanics"

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The collaborative program of research in engineering sciences

Research programs in the following areas are briefly described: High-Temperature Gas-Particle Reactions; Mathematical Modelling of Plasma Systems; Metal Transfer in Gas Metal-Arc Welding; Multivariable Control of Gas Metal-Arc Welding; Synthesis of Heat and Work Integration Systems for Chemical Process Plants; Parity Simulation of Dynamic Processes; Fundamentals of Elastic-Plastic Fracture: Three-Dimensional and Mechanistic Modelling; and Comminution of Energy Materials. Publications from each … more

Date: August 1, 1989

Creator: White, D.C.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Ceramic technology for Advanced Heat Engines Project

Significant accomplishments in fabricating ceramic components for advanced heat engine programs have provided evidence that the operation of ceramic parts in high-temperature engine environments is feasible. However, these programs have also demonstrated that additional research is needed in materials and processing development, design methodology, and database and life prediction before industry will have a sufficient technology base from which to produce reliable cost-effective ceramic engine… more

Date: July 1, 1991

Creator: Johnson, D. R.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Frequency-domain stress prediction algorithm for the LIFE2 fatigue analysis code

The LIFE2 computer code is a fatigue/fracture analysis code that is specialized to the analysis of wind turbine components. The numerical formulation of the code uses a series of cycle mount matrices to describe the cyclic stress states imposed upon the turbine. However, many structural analysis techniques yield frequency-domain stress spectra and a large body of experimental loads (stress) data is reported in the frequency domain. To permit the analysis of this class of data, a Fourier analysi… more

Date: January 1, 1992

Creator: Sutherland, H. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Fatigue and environmentally assisted cracking in light water reactors

Fatigue and stress corrosion cracking (SCC) for low-alloy steel used in piping and in steam generator and reactor pressure vessels have been investigated. Fatigue data were obtained on medium-sulfur-content A533-Gr B and A106-Gr B steels in high-purity (HP) deoxygenated water, in simulated pressurized water reactor water, and in air. Analytical studies focused on the behavior of carbon steels in boiling water reactor (BWR) environments. Crack-growth rates of composite fracture-mechanics specime… more

Date: March 1, 1992

Creator: Kassner, T.F.; Ruther, W.E.; Chung, H.M.; Hicks, P.D.; Hins, A.G.; Park, J.Y. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Structural analysis of a reflux pool-boiler solar receiver

Coupled thermal-structural finite element calculations of a reflux pool-boiler solar receiver were performed to characterize the operating stresses and to address issues affecting the service life of the receiver. Analyses performed using shell elements provided information for receiver material selection and design optimization. Calculations based on linear elastic fracture mechanics principles were performed using continuum elements to assess the vulnerability of a seam-weld to fatigue crack … more

Date: June 1, 1991

Creator: Hoffman, E. L. & Stone, C. M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Statistical fracture mechanics approach to the strength of brittle rock

Statistical fracture mechanics concepts used in the past for rock are critically reviewed and modifications are proposed which are warranted by (1) increased understanding of fracture provided by modern fracture mechanics and (2) laboratory test data both from the literature and from this research. Over 600 direct and indirect tension tests have been performed on three different rock types; Stripa Granite, Sierra White Granite and Carrara Marble. In several instances assumptions which are commo… more

Date: June 1, 1981

Creator: Ratigan, J.L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Investigation of fracture toughness and fracture mechanisms using acoustic emission measurements

This report is the FINAL PROGRESS REPORT'' for the research program Investigation of Fracture Toughness and Fracture Mechanisms using Acoustic Emission Measurements.'' The time period covered by this report is from 1 March 1988 through August 1991. The research program consisted of three separate but closely related investigations: (1) An Investigation of the Acoustic Emission Generated during the Deformation and Fracture of Premium Grade 4340 Steel as a function of Mechanical Properties. (2) A… more

Date: January 1, 1991

Creator: Carpenter, S.H.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Prediction of environmental and strain-rate effects on the stress corrosion cracking of austenitic stainless steels

The stress corrosion cracking (SCC) susceptibility of austenitic stainless steels in high-temperature water is controlled by environmental variables (e.g., dissolved oxygen, corrosion potential, impurities), microstructure (e.g., degree of sensitization), and strain rate. A phenomenological model based on the slip-dissolution mechanism and elastic-plastic fracture mechanics is presented to quantitatively describe the effects of both environment-related parameters and strain rate on SCC in const… more

Date: January 1, 1985

Creator: Maiya, P.S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Interfacial fracture toughness of alumina/niobium systems

The interfacial fracture toughness of an alumina/niobium composite has been measured as a function of phase angle. The interface was formed by solid-state bonding bulk Coor's AD-999 fine-grain alumina with a commercial purity niobium at 1600{degrees}C for 0.5 hr under a pressure of 10.5 MPa. The alumina/niobium system has a number of features which makes it ideal for an investigation of interfacial fracture toughness. From HREM data we estimate that the width of the interface is no more than 10… more

Date: January 1, 1991

Creator: Stout, M.G. (Los Alamos National Lab., NM (United States)); O'Dowd, N.P. & Shih, C.F. (Brown Univ., Providence, RI (United States). Div. of Engineering)

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Method for LEFM analysis of RPV during SBLOCA

A somewhat simplified two-dimensional linear elastic fracture mechanics model of the beltline of a RPV is presented. The fracture mechanics model used tends to be conservative in the sense that it ignores possible beneficial effects of warm prestressing and cladding. For LEFM studies that require a large number of analyses on the same geometry but with different loads and material toughnesses, the superposition principle is an accurate and simple method to determine K/sub 1/, provided that K/su… more

Date: January 1, 1985

Creator: Iskander, S.K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Probability of pipe fracture in the primary coolant loop of a PWR plant. Volume 5. Probabilistic fracture mechanics analysis. Load Combination Program Project I final report

The primary purpose of the Load Combination Program covered in this report is to estimate the probability of a seismic induced LOCA in the primary piping of a commercial pressurized water reactor (PWR). Best estimates, rather than upper bound results are desired. This was accomplished by use of a fracture mechanics model that employs a random distribution of initial cracks in the piping welds. Estimates of the probability of cracks of various sizes initially existing in the welds are combined w… more

Date: June 1, 1981

Creator: Harris, D. O.; Lim, E. Y. & Dedhia, D. D.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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A summary of environmentally assisted crack-growth studies performed at Westinghouse Electric Corporation: Under funding from the Heavy-Section Steel Technology Program

This report was prepared as an attempt to collect the information developed in the crack-growth studies at Westinghouse from 1969 to 1986. Although progress reports were issued regularly over the entire period, the program results have not previously been integrated in a single document. The effect of a pressurized-water environment in the enhancement of fatigue crack growth at low frequencies of loading was discovered by Kondo in 1971 and verified in this program shortly thereafter. To charact… more

Date: May 1, 1988

Creator: Bamford, W.H.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Failure criteria used in a probabilistic fracture mechanics code

Two criteria are implemented in a piping reliability analysis code to assess the stability of crack growth in pipes. One is the critical net section stress criterion. It is simple and convenient but its application is limited to very ductile materials. The other is the tearing modulus stability criterion. This criterion has a solid technical base. However, calculating the J-integral, J, and the associated tearing modulus, T, usually requires a complicated finite element method (FEM). In this pi… more

Date: January 1, 1985

Creator: Lo, T.Y.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Stress fields generated by kinetic energy projectile interaction with ceramic targets

Two-dimensional axisymmetric calculations were performed with the Eulerian hydrocode MESA2D and the Lagrangian structural analysis code PRONTO2D. The calculated stress distributions were compared shortly after impact and found to be similar in magnitude and profile. For certain geometric configurations, the interaction of the kinetic energy penetrators with the ceramic targets produce high compressive principal stresses as well as, significant tensile principal stresses ahead of the projectile/… more

Date: January 1, 1991

Creator: Burkett, M. W. & Rabern, D. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Design guidance for fracture-critical components at Lawrence Livermore National Laboratory

Fracture is an important design consideration for components whose sudden and catastrophic failure could result in a serious accident. Elements of fracture control and fracture mechanics design methods are reviewed. Design requirements, which are based on the consequences of fracture of a given component, are subsequently developed. Five categories of consequences are defined. Category I is the lowest risk, and relatively lenient design requirements are employed. Category V has the highest pote… more

Date: March 3, 1982

Creator: Streit, R. D.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Brief account of the effect of overcooling accidents on the integrity of PWR pressure vessels

The occurrence in recent years of several (PWR) accident initiating events that could lead to severe thermal shock to the reactor pressure vessel, and the growing awareness that copper and nickel in the vessel material significantly enhance radiation damage in the vessel, have resulted in a reevaluation of pressure-vessel integrity during postulated overcooling accidents. Analyses indicate that the accidents of concern are those involving both thermal shock and pressure loadings, and that an ac… more

Date: January 1, 1982

Creator: Cheverton, R.D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Heavy-Section Steel Technology program fracture issues

Large scale fracture mechanics tests have resulted in the identification of a number of fracture technology issues. Identification of additional issues has come from the reactor vessel materials irradiation test program and from reactor operating experience. This paper provides a review of fracture issues with an emphasis on their potential impact on a reactor vessel pressurized thermal shock (PTS) analysis. Mixed mode crack propagation emerges as a major issue, due in large measure to the poor… more

Date: October 1, 1989

Creator: Pennell, W.E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Fracture mechanics assessment of PWR vessel integrity incorporating dynamic crack arrest data above 220 MPa radical m

The present rules and criteria regarding the PTS issue, as established by the US Nuclear Regulatory Commission (NRC), are the PTS rule (Code of Federal Regulations, 1985) and Nuclear Regulatory Guide 1.154 (Regulatory Guide 1.154, 1987). The PTS rule specifics screening criteria in the form of limiting values of reference nil ductility temperature (RT{sub NDT}) of the reactor pressure vessel. Also, the PTS rule requires that a plant specific safety analysis must be performed for any plant that … more

Date: January 1, 1991

Creator: Dickson, T.L. & Cheverton, R.D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Heavy-Section Steel Technology Program fracture issues

Large-scale fracture mechanics tests have resulted in the identification of a number of fracture-technology issues. Identification of additional issues has come from the reactor vessel materials-irradiation test program and from reactor operating experience. This paper provides a review of fracture issues with an emphasis on their potential impact on a reactor vessel pressurized-thermal-shock (PTS) analysis. Mixed-mode crack propagation emerges as a major issue, due in large measure to the poor… more

Date: January 1, 1991

Creator: Pennell, W.E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Rapid heating tensile tests of high-energy-rate-forged 316L stainless steel charged with hydrogen and tritium

Rapid heating tensile tests of uncharged, hydrogen-charged, and tritium-charged-and-aged stainless steels are being used to determine effects of internal hydrogen and helium on fracture modes and mechanical properties at elevated temperatures. Testing of high-energy-rate-forged (HERF) 316L stainless steel at temperatures up to near 1200{degree}C revealed that internal hydrogen has only slight effects on mechanical properties whereas internal helium from radioactive decay of tritium causes sever… more

Date: January 1, 1989

Creator: Mosley, W C

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Evaluation of stainless steel pipe cracking: causes and fixes

Leaks and cracks in the heat-affected zones of weldments in austenitic stainless steel piping and associated components of boiling water reactors (BWRs) have been observed since the mid-1960s. Since that time, cracking has continued to occur and indications have been found in all parts of the recirculation system, including the largest diameter lines. Proposed solutions include remedies primarily intended to produce a more favorable residual stress state, materials which are more resistant to s… more

Date: October 1, 1983

Creator: Shack, W. J.; Kassner, T. F.; Maiya, P. S.; Nichols, F. A.; Park, J. Y.; Ruther, W. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Preliminary test results from the HSST shallow-crack fracture toughness program. [Heavy Section Steel Technology. A36, A517, and A533 B steels]

The Heavy Section Steel Technology (HSST) Program under sponsorship of the Nuclear Regulatory Commission (NRC) is investigating the influence of crack depth on the fracture toughness of reactor pressure vessel steel. The ultimate goal of the investigation is the generation of a limited data base of elastic-plastic fracture toughness values appropriate for shallow flaws in a reactor pressure vessel and the application of this data to reactor vessel life assessments. It has been shown that shallo… more

Date: January 1, 1991

Creator: Theiss, T.J.; Robinson, G.C. (Oak Ridge National Lab., TN (USA)) & Rolfe, S.T. (Kansas Univ., Lawrence, KS (USA). Dept. of Civil Engineering)

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Reactor safety research programs. Quarterly report, July 1-September 30, 1979

The programs include: ultimate heat sink performance measurement; experimental verification of steady state codes: Task A - irradiation results and Task C - code development; graphite nondestructive testing; acoustic emission-flaw relationship for in-service monitoring of nuclear pressure vessels; fuel subassembly procurement and irradiation test program; report of resident engineer at Cadarache, France; core thermal model development; integration of nondestructive examination reliability and f… more

Date: March 1, 1980

Creator: Hooper, J.L. (comp.)

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Application of probabilistic fracture mechanics to the PTS issue

As a part of the NRC effort to obtain a resolution to the PWR PTS issue, a probabilistic approach has been applied that includes a probabilistic fracture-mechanics (PFM) analysis. The PFM analysis is performed with OCA-P, a computer code that performs thermal, stress and fracture-mechanics analyses and estimates the conditional probability of vessel failure, P(F/E), using Monte Carlo techniques. The stress intensity factor (K/sub I/) is calculated for two- and three-dimensional surface flaws us… more

Date: January 1, 1985

Creator: Cheverton, R.D. & Ball, D.G.

Item Type: Article

Partner: UNT Libraries Government Documents Department