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预应力混凝土枕螺栓孔部位受力分析 被引量:2
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作者 马超 牛红凯 窦慧娟 《石家庄铁道学院学报》 2004年第1期10-13,共4页
预应力混凝土轨枕螺栓孔纵裂伤损是我国轨枕伤损中较为严重的一种,是近十年来影响轨枕寿命的主要因素之一。从力学角度,采用三维有限元模型,用SAP90分别对预应力混凝土轨枕上道前和上道后螺栓孔部位的受力进行了详细的计算和分析,总结... 预应力混凝土轨枕螺栓孔纵裂伤损是我国轨枕伤损中较为严重的一种,是近十年来影响轨枕寿命的主要因素之一。从力学角度,采用三维有限元模型,用SAP90分别对预应力混凝土轨枕上道前和上道后螺栓孔部位的受力进行了详细的计算和分析,总结出螺栓孔区域受力变化规律,并指出螺栓孔部位局部拉应力过大是造成螺栓孔纵裂的根本原因。 展开更多
关键词 铁路工程 应力混凝土枕 螺栓孔 受力分析 纵裂原因 立体模型 局部拉应力
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Segmentation of copper alloys processed by equal-channel angular pressing
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作者 Omid NEJADSEYFI Ali SHOKUHFAR Vahid MOODI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第8期2571-2580,共10页
This research provides experimental evidence for localized shear, billet cracking, and segmentation during the processing of various copper alloys. The results demonstrate that although many parameters affect the shea... This research provides experimental evidence for localized shear, billet cracking, and segmentation during the processing of various copper alloys. The results demonstrate that although many parameters affect the shear localization, there is a direct relation between segmentation and alloy strength (hardness) that is related to the alloying elements and constitutive phases. For instance, alpha brass is successfully processed by ECAP at room temperature, but alpha/beta brasses fail even at a temperature of 350 °C. Finite element simulation of cracking and segmentation was performed using DEFORMTM to investigate the influence of different parameters on segmentation. The results confirm that friction and processing speed have narrow effects on attaining a perfect billet. However, employing back pressure could be reliably used to diminish shear localization, billet cracking, segmentation, and damage. Moreover, diminishing the flow localization using back pressure leads to uniform material flow and the billet homogeneity increases by 36.1%, when back pressure increases from 0 to 600 MPa. 展开更多
关键词 back pressure BRASS BRONZE DAMAGE flow localization stress-strain behavior tensile strength DUCTILITY
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辊类部件断轴原因、预防及修复
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作者 刘云龙 《西南造纸》 1999年第2期31-32,共2页
关键词 断轴 轴头 平行度 疲劳断裂 水平度 应力集中 下压榨辊 预防措施 局部附加应力 变动应力
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