In stress measurement using indentation technique, the value of stress was calculated by the difference in load with and without residual stress. Even in the measurement of asymmetric stress filed using asymmetric indenter such as Knoop indenter, the reference load without residual stress was required for calculating the existing residual stress. However, it takes a lot of work to apply stress measurement of the part with hardness change due to mechanical machining or welding-induced phase transformati...
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Semi-nondestructive Measurement of Asymmetric Residual Stress Field using Indentation Technique without Reference Load

This study presents an advanced method to estimate mechanical properties of structural steels through the instrumented indentation techniques using spherical indenter. Finite element analysis model of instrumented indentation testing was constructed to investigate the effect of stress.strain curve of materials on the indentation load.depth curve and the indentation contact radius. From calculation results, new estimation formulae for the representative stress and stain relations were established. Meanwhile,...
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An Advanced Method to Estimate Mechanical Properties of Structural Steels through Instrumented Spherical Indentation Techniques

１．はじめに1.1　規格・基準の性格と社会的必要理由　社会を集団と呼ぶことにして，人間は一人では生きていけず他人とのかかわりを持って始めていきていけることは当然のことで，このことを称して種の保存とか集団の維持とかのように言われてきた．個と集団の関係は，部分と全体の関係のように極めて重要な普遍性を持った関係にある．個と集団の関係には，やっかみなど集団から来る感情や個を殺して集団の決まりに従うとか，が考えられるが，それらの中でも個が守らなければならない規則という側面が規格・基準に関連して考えられなければならな......

This paper studies the effect of initial residual stress on high-precision manufacturing for infrastructure integrity technology. Welding distortion decreases the strength of welded structure. Straightening causes secondary deformation. Althogh welding distortion should be reduced, handling welding distortion is difficult. One of the reason is the dispersion o f cutting and welding distortion. In one of the contributing factor there are an influence of initial residual stress. When the equalization of init...
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Investigation of high-precision manufacturing for infrastructure integrity technology

Considering the effect of the complex phenomena during the welding, for example thermal deformation, phase transformation, residual stress, etc, is important when the welding process is used. All of the effects are caused by heat input and conduction during the welding. Therefore, evaluating the heat input and conduction properties during the welding is so important in order to understand and control the phenomena. However, the weld pool has a fluid flow with thermal conduction, a free surface, and an ...
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Study for Evaluation of Temperature Field during Welding using Particle Method

This study proposes a numerical analysis method for evaluation of strength properties related with mater ial control and material maintenance. The method using generalized Voronoi diagram for modeling of hete rogeneity of grain shape is proposed. Effect of grain shape on strength properties is analyzed by the fi nite element method. ...
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Investigation of Material Control and Material Maintenance Method by Evaluation of Strength Properties Considering Grain Shape

To clarify the effects of residual stress and hardening on intergranular stress corrosion cracking (IGSCC) behavior in welds of low-carbon austenitic stainless steels with surface machining, residual stress and hardness were evaluated by 3-dimentional thermo elastic-plastic analysis and grain boundary sliding behavior was examined using a constant strain rate tensile test. It was revealed that grain boundary sliding occurred in the material at 561K by the tensile test with the numerically simulated t...
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Effect of Residual Stress and Hardening on Grain Boundary Sliding in Welds of Low-carbon Stainless Steels with Surface Machining

Abstract Surface finishing methods, such as Water Jet Peening (WJP), have been applied to welds in some major components of nuclear power plants as a counter measure to Primary Water Stress Corrosion Cracking (PWSCC). In addition, the methods of surface finishing (buffing treatment) is being standardized, and thus the buffing treatment has been also recognized as the well-established method of improving stress. On the other hand, the long-term stability of peening techniques has been confirmed by acc...
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Prediction method of long-term reliability in improving residual stresses by means of surface finishing

This paper proposes a maintenance activity model that considers not only routine maintenance activity but also functional maintenance including improvement/modification. Required maintenance types are categorized, and limitation of Activity Domain Integration Diagram (ADID) proposed by ISO18435 are discussed based on framework for life cycle maintenance management of manufacturing assets. Then, we proposed extension ADID model for plant maintenance activity model considering functional improvement/mo...
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Basic study of the plant maintenance model considering plant improvement/modification

This study proposes a maintenance activity model that considers not only routine maintenance activity but also functional mainte nance including improvement/modification Required maintenance types are categorized, and limitation of Activity Domain Integrati on Diagram (ADD) proposed by ISO18435 are discussed based on framework for life cycle maintenance management of manufacturing as sets. Then, we proposed extension ADD model for plant maintenance activity model considering functional improvement/modifica...
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Basic study of the plant maintenance model considering plant improvement/modification