Author J.H. Lee 1)
,
K.B. Yoon2)
,
Y.J. Kim3)and U.B. Baek4) 1) Engineering Research Department
,
Korea Institute of Nuclear Safety
,
P.O. Box 114
,
Yoosung
,
Taejon 305600
,
Korea2) Department of Mechanical Engineering
,
Chung Ang University
,
221 Huksuk
,
Dongjak
,
Seoul 156756
,
Korea3) Department of Mechanical Engineering
,
Sungkyunkwan University
,
300 Chunchun
,
Jangan
,
Suwon 440746
,
Korea4) Failure Prevention Research Center
,
Korea Research Institute of Standards and Science
,
P.O. Box 102
,
Yoosung
,
Taejon 305600
,
KoreaManuscript received 18 October 1998
金属学报(英文版)
Most of the assessment equations for Ct which is a wellknown fracture parameter characterizing high temperature crack growth rates, have limited applicability to constant load conditions after sudden loading. However, crack growth due to creep can also occur under load varying conditions when load rising time is so long that accumulated creep deformation near the crack tip is not negligible.In this paper, the estimation equation of the Ctparameter which can be applied to the case of slow load rising, i.e., (Ct)r, is explained. And the correlation between (Ct)r at the end of the load increasing period and Ct at the beginning of the succeeding load hold period is discussed. Finite element analyses of several cases with various loading conditions were performed and results were presented to show the effectiveness of the proposed Ct estimation scheme. The general applicability of the equation is also discussed.
关键词:
creep
,
null
,
null
,
null
,
null
,
null
Z.Z.Lǖ
金属学报(英文版)
A numerical simulation method is presented for the random-fuzzy safety analysis of an aero engine disk. Based on the equivalent transformation from a fuzzy variable to a random variable, the equivalent random Probability Density Functions(PDFs) are got from their corresponding Fuzzy Possibility Distributions(FPDs) for the fuzzy variables. In that case the perfect numerical simulation method for the random uncertainty is employed to solve the fuzzy uncertainty. For the complex structure such as the aero engine disk with implicit relationship between the input basic variable and the response variable, the equivalent PDFs of the input basic variables are delivered simultaneously to the response variable by an empirical PDF, which is simulated by Finite Element Method(FEM). Then, in view of the fuzzy application requirement occurring in engineering usually, the reliability definition and calculation are discussed for the aero engine disk with multiple fuzzy failure modes. On the other hand, through the inverse transformation of the fuzzy variable to the random variable, the FPDs of the response variables can be calculated from their empirical PDFs as well.
关键词:
random
,
null
,
null
Chinese Physics Letters
Using nuclear magnetic resonance techniques with a solution of cytosine molecules, we show an implementation of certain quantum logic gates (including NOT gate, square-root of NOT gate and controlled-NOT gate), which have central importance in quantum computing. In addition, experimental results show that nuclear magnetic resonance spectroscopy can efficiently measure the result of quantum computing without attendant wave-functions collapse.
关键词:
computation;universal;computer
Journal of Nuclear Materials
Based on the measured stress-strain curves under different temperatures and strain rates, a series of flow stress constitutive equations for SA508-3 steel were firstly established through the classical theories on work hardening and softening. The comparison between the experimental and modeling results has confirmed that the established constitutive equations can correctly describe the mechanical responses and microstructural evolutions of the steel under various hot deformation conditions. We further represented a successful industrial application of this model to simulate a forging process for a large conical shell used in a nuclear steam generator, which evidences its practical and promising perspective of our model with an aim of widely promoting the hot plasticity processing for heavy nuclear components of fission reactors. (c) 2011 Elsevier B.V. All rights reserved.
关键词:
low-alloy steels;low-carbon steel;hot deformation;mechanical-properties;fracture-toughness;temperature;austenite;working
Materials Science and Technology
In nuclear plant the protection of the H(2)BO(4) solution seal areas of AISI 316L austenitic steel is accomplished by Stellite 6 plasma cladding layer. Wear defects created in service required the part to be replaced or repaired. No existing repair technologies were practical. Electrospark deposition (ESD) was to repair defects, enabling the parts to be placed back in service. In this paper the authors report the results obtained depositing directly a layer of Stellite 6 alloy onto a 316L austenitic stainless and Stellite 6 plasma cladding layer by using ESD technique. Electrospark deposition can apply metallurgical bonded coatings without the need of post-heat treatment. Structure, hardness, chemical composition and morphology of the ESD coating have been analysed. By electrochemical measurements it is inferred that the corrosion resistance of the ESD coating is comparable to that of the 316L and Stellite 6 plasma cladding layer. The hardness improvement was ascribed to the refine microstructure and the rapid solidification.
关键词:
Electrospark deposition;AISI316L stainless steel;Plasma cladding;Stellite 6
