作者: Zi Rui Pang, Suo Xian Yuan, Wan Shan Wang, Chun Xia Zhu

摘要: In this paper, we emphasize that residual stresses in a ground surface are primarily
generated due to grinding zone temperature effect, and discuss grinding zone temperature can be
debased based on characteristics of the thin vitrified bond CBN wheel and quick-point grinding. Via
experimental results of 5 group working procedures, we find that surface roughness Ra showed a
tendency to reduce slightly with infeed rate reduced, cut depth increased, grinding wheel speed and
grinding variable angle increased, the favorable residual compressive stress could obtained along
with variables angle(α, β) increased, the sub-surface white etching layer and tempered martensite
layer in size become thinner with α, β angle and grinding wheel speed increased when removal rate
Z=0.06mm3/mm keep constant in quick-point grinding, by contraries, surface quality were
decreased entirely when variables angle(α, β) equal to zero. The results indicate it is important that
grinding variable angle were choice in quick-point grinding for to obtain favorable residual
compressive stress.

239

作者: Jun Zhou, Jian Feng Li, Jie Sun

摘要: In this paper, the micro-scale machining characteristics of a non-ferrous structural alloy, aluminum 7050-T7451 is investigated through a series of cutting experiments. The effects of cutting speed and undeformed chip thickness on the chip geometry, cutting ratio, effective rake angle and shear angle in orthogonal micro-scale cutting of Al 7075-T7451 are presented. Explanations for the observed trends are also given.

657

作者: Ryo Nakagawa, Takeharu Matsuno, Yasuo Marumo, Yuya Hayano, Li Qun Ruan, Hidetoshi Sakamoto, Hiroshi Harada

摘要: Characteristics of slide-bend forming were investigated. In this process, foil specimens can be bent to various shaped products by indenting and sliding a tool. The effects of the tool indentation load, the foil thickness and the number of slide repetition on the bending angle were examined experimentally for three kinds of foil materials. In addition, the deformation of bent region was examined using a rigid-plastic finite element analysis. Bending angle increased with increasing the indentation load or decreasing the foil thickness. When the number of slide repetition increased, the bending angle increased slightly. The slide repetition can be effective for adjusting bending angle slightly. By sliding a thin edge-shaped tool relative to the foil specimen, bending angle and radius of curvature of specimens can be controlled freely.

342

作者: Zhi Ping Yin, Jiong Zhang, Jin Guo, Qi Qing Huang

摘要: The finite element software ANSYS was employed to create a finite element model of the cracked wing beam integrated structure, and the stress field of the crack tip was got by the material nonlinearity (elastic-plastic) analysis method. Based on the maximum tensile stress theory criteria, the crack deflection angle was obtained. The crack deflection angles with different geometry parameters (crack length, wed thickness, the height-thickness ratio of the stringer, cross-sectional area, and the location of the stringer) of the wing beam integrated structure were calculated and compared with each other. So the influences of the geometry parameters of the wing beam integrated structure on the crack deflection were studied. The crack deflection angles obtained in elastic analyzing and elastic-plastic analyzing were compared to investigate the effects of the material property on the crack deflection angle.

101

作者: Hannah Pearson, Mark Evernden, Richard Harris

摘要: Presented in this paper are the results of practical tests to determine some key material properties of engineered timber, in particular glulam. The results are discussed and compared with three known failure criterion, Hankinsons formula, The Tsai-Wu criterion and Maximum stress theory to determine if they are appropriate models for predicting the properties of glulam. The properties considered have been chosen with respect to a connection system for use in folded plate structures utilizing embedded rods. This paper considers the effect of the timber grain angle on the compression, tensile and steel dowel rod pull-out strengths. The test data shows that Hankinson and Tsai-Wu are both good models to predict both the compression and tensile behavior of engineered timber products at non-tangential angles, whereas maximum stress theory had less correlation and over predicts the results and would not be recommended for use in engineered timber materials.

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