Authors: Makoto Hayashi, Shinobu Okido
Abstract: In the X-ray diffraction method, the diffraction intensity, the half-value width, the residual stress and the amount of residual austenitic phase can be measured. By using these parameters, the quality, the mechanical properties and the fatigue strength of materials, the remaining life of fatigue and creep can be evaluated. While the X-ray study has been widely performed for the various kinds of industrial fields in the laboratory, the applications to the actual structure and components have not so many. However, the small size X-ray residual stress analyzer, the position sensitive detector and the micro area diffraction apparatus have been developed for these twenty years. Thus the X-ray diffraction methods have been variously applied to the
industrial fields. The X-ray diffraction methods were used to be applied for the large scale structures and machine parts, but recently applied to the semi-conductor fields. On the other hand, the neutron diffraction method has been introduced to measure the residual stresses in the internals of components because of its deep
penetration depth. Based on the experiences of X-ray diffraction method, the various kinds of techniques have been proposed. In this paper, the applications of X-ray and neutron diffraction method to the reliability evaluations of structural components and the electronic devices are described.
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Authors: Dong Woo Lee, Seok Swoo Cho, Won Sik Joo
Abstract: A roller mill is composed of several rollers, rotational table liners, hydraulic cylinders and
raw materials are ground between the rollers and the table with the assistance with a shearing and
compressive force. It has been reported that an unexpected fatigue failure occurred in a table liner in
the course of grinding portland cement. It is subjected to the cyclic bending stress by the rollers load
and the centrifugal force by the table rotation and fractures at the edge of grinding path of outer roller.
It demands design life 4×107 cycles but has fatigue life 4×106 ~ 8×106 cycles. The purpose of this
study is to reveal the failure mechanism of the table liner occurring in the grinding operation of roller
mill and to show the structural design guidelines for reducing the fatigue failure.
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Authors: Chong Lue Hua, Gui Cheng Wang, Hong Jie Pei, Gang Liu
Abstract: Thermal stresses of grinding plays an important role on the fatigue and wear resistance of the component. A comprehensive analysis of thermal stress induced by surface grinding has been conducted with aid of the finite element method. To obtain a reliable figure of thermal stress induced by grinding, temperature-dependent properties of workpiece materials were taken into account. The developed finite element procedure has also been applied to calculate the surface and sub-surface thermal stress induced by moving source of triangular heat when convection and radiation is occurred over the whole work. Based on an analysis of the effects of wheel velocity on the thermal stress distributions in an elastic-plastic solid, some important conclusions were given.
2211
Authors: Wen Qing Wu, Xue Yuan Ma, Shuai Chen
Abstract: The compressive mechanical performance of bamboo strip plywood was studied in the paper. Based on analysis of the related experiments datum , the principal compressive mechanical performance under static load were expounded perfectly, and a number of mechanical parameters such as compressive strength, compressive elastic modulus and compressive constitutive relations were obtained. It was shown that the mechanical performance of bamboo strip plywood was better than that of wood material such as Northeast larch, the compressive elastic modulus was lower than that of concrete, so that there existed a more great deformation when the bamboo beam structure was loaded, and the constitutive relations of bamboo materials showed that there was excellent ductility with an obvious characteristic of plastic deformation . This research result showed that there was a great significance on studying and application of bamboo bridges in the future.
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Authors: F.C. Cione, J.L. Rossi, A.C. Souza, S. Delijaicov, M.A. Colosio
Abstract: Many engineering specifications, manufacturing procedures, inspection and quality control have begun to require that the residual stress of a particular component be evaluated. This is becoming as commonplace as the demands on the mechanical properties. In the country there are few research laboratories qualified to perform these tests and also found a worrying lack of skilled labor. Studying the formation and distribution of residual stress fields will improve the operational criteria of wheel safety, among other gains. It is known that these residual stress fields could be added to the effects of system load (tare weight plus occupation of vehicle traction, braking and torque combined). The results obtained used drilling method and rosette type strain gages, are convergent with similarity to those obtained using FEA simulation over critical region for global and superficial in principal stresses mode. The relevance of the present study and research on residual stresses meets safety improvements in cars wheel industry.
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