Papers by Keyword: Representative Stress

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Authors: Yong Yun Nam, Seung Ho Han, Jeong Woo Han, Byung Chun Shin
Abstract: The hot spot stress or the notch strain alleviates the welding detail dependency of S-N curve to some extent. This paper suggests a new stress model which alleviates the dependency further, thus the fatigue strengths of several welding details of same material can be evaluated with the S-N curve of the base material. A stress at the hot spot of a weld joint is decomposed into two components; linear rising one, and rapid rising one which is inversely proportional to the distance from the hot spot. For the stress decomposition, a formula is proposed with which the configuration of stress distribution near a hot spot is fitted exactly. The new stress model makes use of a geometric characteristic of the stress distribution curve by the formula. The stress model is applied to five different weld joints. As the result, the experimental fatigue data are plotted very closely to the S-N curve of the base material
Authors: Eun Chae Jeon, Min Kyung Baik, Sung Hoon Kim, Baik Woo Lee, Dong Il Kwon
Abstract: A new method [1] to evaluate indentation flow curves using an instrumented indentation test has been applied to many materials for several years. Though the method produces relatively good results compared to uniaxial tensile tests, a few parameters had not been verified by theoretical or numerical methods. In this study, proportional constants of representative strain and representative stress were verified using finite element analysis and proven to be unaffected by the elastic property and strain level. The constants were generally dependent on the plastic property; however, one combination of the constants is independent of all properties. The values of this combination are consistent with early research and produced overlapping indentation flow curves with uniaxial curves.
Authors: Wei Chen, De Jun Ma, Jia Liang Wang, Yong Huang
Abstract: Method for determining the plastic properties of metallic materials was proposed based on the functional relationships between representative stress, representative strain and nominal hardness which were established with the aid of dimensional analysis and finite element simulation. The errors of 0.2% yield strength and strain hardening exponent of five engineering metals were from-17.1% to 15.4% and from -0.125 to 0.11, respectively,which satisfied the need of engineering application and verified the effectiveness of the method.
Authors: I. Nyoman Budiarsa, Mikdam Jamal
Abstract: In this work, finite element (FE) model of spherical indentation has been developed and validated. The relationships between constitutive materials parameters (σy and n) of elastic-plastic materials, indentation P-h curves and hardness on spherical indenters has been systematically investigated by combining representative stress analysis and FE modelling using steel as a typical model material group. Parametric FE models of spherical indentation have been developed. Two new approaches to characterise the P-h curves of spherical indentation have been developed and evaluated. Both approaches were proven to be adequate and effective in predicting indentation P-h curves. The concept and methodology developed is to be used to predict Rockwell hardness value of materials through direct analysis and validated with experimental data on selected sample of steels. The Hardness predicted are compared with the experimental data and showed a good agreement. The approaches established was successfully used to produce hardness values of a wide range of material properties, which is then used to establish the relationship between the hardness values with representative stress.
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