共查询到20条相似文献,搜索用时 9 毫秒
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Russian Engineering Research - 相似文献
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M.O.A. Mokhtar 《Tribology International》1981,14(2):113-119
The performance characteristics and design data for journal bearings with a precise floating ring inserted between the rotating journal and a rigid housing are investigated theoretically. Based on convenient boundary conditions, a theory has been developed to predict the floating ring behaviour. Performance charts are presented with curves provided with optimum design areas to help in practical design applications. Induced ring speed, hydrodynamic behaviour, oil film variation, load capacity and frictional drag could thus be analytically or graphically determined. Results indicate that the ring dimensions are a dominant factor in deciding the final bearing behaviour and that the oil film thickness between the ring and the housing is much thinner than that between the journal and the ring. The floating ring bearing showed less frictional power loss than a fixed sleeve bearing, but this may have been achieved at the expense of the load capacity. 相似文献
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This paper presents a design methodology for determining configurations of slider air bearings considering the randomness
of the air-bearing surface (ABS) geometry by using the iSIGHT. A reliability-based design optimization (RBDO) problem is formulated
to minimize the variations in the mean values of the flying heights from a target value while satisfying the desired probabilistic
constraints keeping the pitch and roll angles within a suitable range. The reliability analysis is employed to estimate how
the fabrication tolerances of individual slider parameters affect the final flying attitude tolerances. The proposed approach
first solves the deterministic optimization problem. Then, beginning with this solution, the RBDO is continued with the reliability
constraints affected by the random variables. Reliability constraints overriding the constraints of the deterministic optimization
attempt to drive the design to a reliability solution with minimum increase in the objective. The simulation results of the
RBDO are listed in comparison with the values of the initial design and the results of the deterministic optimization, respectively.
To show the effectiveness of the proposed approach, the reliability analyses are simply carried out by using the mean value
first-order second-moment (MVFO) method. The Monte Carlo simulation of the RBDO’s results is also performed to estimate the
efficiency of the proposed approach. Those results are demonstrated to satisfy all the desired probabilistic constraints,
where the target reliability level for constraints is defined as 0.8. 相似文献
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A.B. Duncan 《Tribology International》1980,13(5):253-256
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Optimum design of short journal bearings by enhanced artificial life optimization algorithm 总被引:4,自引:0,他引:4
This paper presents an optimum design of high-speed short journal bearing using an enhanced artificial life algorithm (EALA) to compute the solutions of optimization problem. The proposed hybrid EALA algorithm is a synthesis of an artificial life algorithm (ALA) and the random tabu search method (R-tabu method) to solve some demerits of the ALA. The emergence is the most important feature of the artificial life which is the result of dynamic interaction among the individuals consisting of the system and is not found in an individual. The artificial life optimization algorithm is a stochastic searching algorithm using the feature of artificial life. The feature of R-tabu method, which prevents converging to the local minimum, is combined with the ALA. One of the features of the R-tabu method is to divide any given searching region into several sub-steps. As the result of the combination of the two methods, the EALA not only converges faster than the ALA, but also can lead to a more accurate solution. In addition, this algorithm can also find all global optimum solutions. We applied the hybrid algorithm to the optimum design of a short journal bearing. The optimized results were compared with those of ALA and successive quadratic programming, and identified the reliability and usefulness of the hybrid algorithm. 相似文献
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《世界制造技术与装备市场》2002,(6):14-14
并行工程、精益生产、敏捷制造和绿色制造是现代企业的新型高效运行模式。他们之间不是相对、独立、互斥的关系,而是互相补充、互相促进、共同发展的关系。从图1可 相似文献
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C K Waterson 《Medical instrumentation》1983,17(6):379-382
The anesthesia machine is a major component in an integrated anesthesia care system. It can be considered in terms of the functional subsystems responsible for gas proportioning, anesthetic vapor delivery, patient ventilation, and waste gas scavenging. Alternative technologies for these functional units should be examined in light of the disadvantages inherent in present machines. Safety features, often added on an ad hoc basis, should instead be designed into the machine itself. The anesthesia delivery system should include feedback about the patient status and device performance, as well as provide for the delivery of anesthetic and pharmacologic agents. Improvements in performance and provisions for automation of some functions should be considered as future design criteria. 相似文献
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In recent years it has become possible to accurately model the performance characteristics of externally pressurised orifice compensated gas bearings. Also, and of equal importance, it is now possible to evaluate the effects of errors, and to establish the significance of these errors on the idealised bearing performance.This paper considers typical errors which are encountered in manufacture and the significance of each effect. Finally, evidence is presented which demonstrates the correlation that can be achieved between theoretical models and experimental measurements. The charts presented in this paper may be used by designers to assist in accurately predicting the performance of bearings whose errors of size and form (effect of tolerances) have been determined 相似文献
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Attention focuses on how the roughness and the configuration of microirregularities on the frictional surfaces of slip bearings affect their interaction and wear. 相似文献
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An investigation of three-dimensional scanning of human body surfaces and its use in the design and manufacture of prostheses 总被引:13,自引:0,他引:13
Bibb R Freeman P Brown R Sugar A Evans P Bocca A 《Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine》2000,214(6):589-594
The capture of highly accurate data describing the complex surfaces of the human body may prove extremely useful in many medical situations. The data provide a method of measuring and recording changes to the surface of a patient's soft tissue. The data may be applied to computer-controlled manufacturing techniques, such as rapid prototyping (RP). This enables accurate physical replicas of the patient topography to be produced. Such models may be used as an aid in the design and manufacture of prostheses. This paper describes an investigation aimed at identifying problems that may be encountered when scanning patients and describes the application of the resulting data in the design and manufacture of facial prostheses. The results of the experiment are presented together with a discussion of the accuracy and potential advantages afforded by this approach. 相似文献
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研究利用层次分析法(AHP)与排序组织法(PROMETHEE)进行产品设计方案排序与优选问题.在建立定性与定量相结合的决策准则体系的基础上,首先使用AHP确定属性权重,然后使用PROMETHEE计算偏好指标和各方案的净流,获得方案的完全序.该方法以设计者的目标与价值观为导向,又兼顾了属性信息的不确定性,具有一定的应用价值. 相似文献
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介绍了基于降低成本和提高生产率的设计——面对制造的设计 (DFM)和面对装配的设计 (DFA) ,并提出了实施 DFM和 DFA技术的策略 相似文献
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从设计纺机空间凸轮的角度,分析了空间凸轮的设计方法和设计规律。运用反求的方法,对反求三坐标数据的测量和处理方法进行了阐述,同时对纺机空间凸轮的加工规律和特性进行了剖析,充分利用先进的CAD/CAM集成软件Pro/Engineer强大的设计和加工功能,比较系统地设计了纺机空间凸轮。利用Pro/Engineer加工模块,对纺机空间凸轮进行了数控加工,生成数控加工程序。 相似文献