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利用三维有限元方法建立层状复合凸轮与钢管的过盈装配模型,模拟过盈装配过程中凸轮等效应力的分布规律以及不同内层材料和内层厚度对凸轮装配内应力的缓解效果,并进行实验验证。结果表明:与45#钢内层材料相比,粉末冶金材料(Fe-Cu-C)具有更好的缓解应力效果,在过盈量为0.08 mm时,复合凸轮表面应力仅为前者的38%,实验验证表面应力为前者的40%,误差仅为5%,模拟与实验结果基本一致。利用该模型对复合凸轮的层状厚度进行了优化设计,内层厚度允许范围为1.75~2.25 mm,最佳厚度为2.05 mm。 相似文献
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根据压痕硬度测试理论,建立了二维轴对称有限元模型.通过有限元手段分析了纯钛在载荷作用下的压入过程,了解在压痕硬度试验过程中压痕周围所产生的应力分布及屈服区域.通过载荷位移曲线得出最大压入深度,从而计算出布氏硬度. 相似文献
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冷装配工艺在设备检修中的应用 总被引:1,自引:0,他引:1
本文介绍了一种对设备上过渡和过盈配合轴承、套孔进行装配的新工艺,同传统工艺相比,提高了装配质量,大大缩短了时间,降低了工人劳动强度。 相似文献
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报道了涂层压入仪的研制背景、结构原理、主要技术特性及其应用举例,该仪器具有连续加载卸载功能并配有声发射和光学系统,能测量并记录连续的载荷与压入深度关系曲线,能用声发射系统对测试过程中涂层试样的开裂和剥落进行动态监测,并确定对应的载荷,用涂层压入仪作界面压入测得厚涂层与基体界面开裂的临界载荷pw可反映涂层的结合强度;也可正面压入考察薄膜与基体的结合,区分薄膜开裂和剥落并精确测定其对应的载荷值,用加载过程中发生初始剥落的载荷表征膜的结合强度,涂层压入仪还可用于膜韧性、膜和膜,基断裂韧性、离子氮化层脆性等的评价,测定块体材料硬度、塑性功、弹性功、弹塑性比等性能指标。 相似文献
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转炉扭力杆缓冲装置三维非线性有限元分析 总被引:1,自引:0,他引:1
针对某厂扭力杆缓冲装置运行时出现的问题,运用有限元软件建立其整体装配非线性有限元模型,充分考虑螺栓预紧力、零件间过盈配合及接触非线性,分析扭力杆缓冲装置在最大倾动力矩与事故状态下的应力分布及强度,提出螺栓联接修改建议。研究结果表明:螺栓根部出现严重的应力集中现象,这与螺栓过早损坏是一致的;扭力杆在最大倾动力矩作用下安全裕度较大;在事故状态下最大应力出现在扭力杆键槽附近,其值接近材料疲劳强度极限。研究结果为螺栓联结的改进提供了依据,也为扭力杆的设计制造与检修提供理论依据。 相似文献
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利用ANSYS有限元分析软件,对济钢第一小型轧钢厂中轧减速机输出轴无键套联接与轴的配合进行建模,并模拟计算配合应力,得出过盈量与最大预应力的对应关系,为减速机输出轴无键联接套的过盈量设计计算提供了理论依据。 相似文献
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轧机机架的动态特性仿真与结构优化 总被引:1,自引:0,他引:1
应用有限元分析方法,对某铝带二辊轧机机架装配系统进行了动态特性仿真,得出了固有频率和振型的变化规律.针对轧机机架的薄弱环节,通过参数化方法进行灵敏度分析和结构优化设计,使系统的动态特性得到提高,该结论为高性能轧机的设计优化,提供了一定的参考. 相似文献
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通过对焦炭在高炉内的历程及其变化规律的剖析,阐述焦炭热性能指标的意义,形象地把焦炭在高炉内的损耗分为三部分(M1,M2,M3)。指出M2对焦比及焦炭价格有一定的指导作用。 相似文献
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K Ohta M Nishi M Ueda S Ohyama T Matsubara T Takahashi T Nakajima 《Canadian Metallurgical Quarterly》1998,99(9):589-594
Cancer of the cardia is traditionally discussed with cardiac cancer of the lower portion of the esophagus and upper gastric cancer invading the esophagus, and the specific characteristics of cancer of the cardia have never been clearly defined. We reviewed the outcome of 172 patients with adenocarcinoma of the cardia who had undergone radical surgery between 1949 and 1994 in the Division of Gastrointestinal Surgery of the Cancer Institute Hospital. The centers of the tumors were located within 2 cm above and below the boundary between the esophagus and the stomach, and their longitudinal diameter was less than 8 cm. We divided the patients into an early period (1949-1979; n = 79) and a late period (1980-1994; n = 93), and focused on the historical transition. There were no differences in patient gender or histology between the two periods. However, the late period was associated with fewer cases of esophageal invasion and shorter longitudinal diameter, as the age of the population advanced. The number of advanced cancers such as the localized and infiltrative type had decreased, and early cancer and early clinical stage had become more common, but despite the fact that the number of early cancers had increased, extended dissection, such as thoracic and paraaortic lymph node dissection, was performed more frequently. By clinical stage, the long-term outcome markedly improved in Stage I patient in the late period, and tended to improve in Stage II and III patients. This appears to have been attributable to the prevention of micrometastasis by extended dissection, although the number of early cancers is another major potential cause. There were no differences in the outcome of Stage IV patients between the two periods, and further advances in multimodality therapy must be awaited. The range of resection is basically proximal gastrectomy, and if there are adequate indications, the prognosis is favorable. In view of the status of lymphatic flow and lymph node metastasis, and long-term results, lateroaortic lymph node dissection is important. Since the number of early cancer patients has been increasing, if intraabdominal recurrence is prevented, intrathoracic lymph node dissection will contribute greatly to the outcome of such patients. 相似文献
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The effect of 20 different antibiotics on chemotaxis by human neutrophils was studied. Human leukocytes incubated with chloramphenicol, rifampin, sodium fusidate, and tetracyclines in vitro showed markedly depressed migration. The mechanisms by which these antibiotics affect leukotaxis are discussed. 相似文献
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TA Solokhina LS Shevchenko IuV Se?ku EG Rytik LV Besedina TS Veshchugina 《Canadian Metallurgical Quarterly》1998,98(6):42-46
Usage of quality of life of psychiatric patients' relatives as the parameter of estimation of the quality of psychiatric care is considered. By means of standard questionnaire elaborated by the authors as well as by means of both individual and group conversations the quality of life was analyzed in 40 relatives which lived together with psychiatric patients. Different spheres of their life and difficulties (financial, social-psychologic, production) were examined in families with such patients. The defects of psychiatric care that had direct influence on the quality of life of the psychiatric patients' relatives are outlined. 相似文献
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Some theories of personality hold that an individual's perception of others is influenced by his own personality characteristics; more specifically, that a trait of low social value will be projected more into others, and that insight into the possession of these characteristics reduces this distortion. These 2 hypotheses were tested by having a group of college students rate each other (including themselves) on degree of friendliness or hostility. Agreement with group rating about self yielded the insight score. In general, the hypotheses were supported; the "friendly" Ss were most accurate in their perception of others, and insight was positively associated with accurate perception. From Psyc Abstracts 36:04:4HL16M. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献