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聚晶金刚石复合片硬质合金层磨削过程数值模拟 总被引:1,自引:1,他引:0
建立了聚晶金刚石复合片硬质合金层磨削过程中的传热学模型,并基于有限元原理,利用工程数值模拟软件ANSYS对硬质合金层磨削时的温度场及应力场分布进行了模拟,分析了不同磨削参数对磨削温度场、应力场及复合片变形量的影响规律。研究表明,磨削深度、砂轮速度等参数对复合片变形量影响较大,磨削深度增大,磨削表面温度升高,残余应力增大,变形加剧。砂轮速度增大,磨削表面温度升高,残余应力增大,变形量也变大。利用有限元方法是研究磨削温度场、应力场及复合片变形规律的一种有效方法。 相似文献
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针对喷丸强化过程数值仿真及强化效果快速预测方法进行了深入研究。针对航空铝合金材料,利用显式动力分析软件LS-DYNA,进行了喷丸强化过程有限元数值仿真,研究了球形弹丸速度、弹丸大小、入射角度对喷丸残余应力场的影响规律;提出了基于Kriging模型的喷丸强化效果快速预测方法;进行概率有限元分析,建立了喷丸强化Kriging数值模型,并构建了关键响应参数与多维工艺变量之间的响应曲面。分析结果表明,喷丸速度、弹丸大小、入射角度对残余应力场分布有显著影响。Kriging近似模型预测结果与有限元计算结果相吻合,说明所建立的Kriging近似模型具有很高的近似精度和可靠性,可以代替复杂的有限元分析。 相似文献
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温度循环条件下固体装药应力及累积损伤研究 总被引:2,自引:0,他引:2
为考察外界环境对固体火箭发动机的影响,基于热粘弹性模型,利用有限元方法对其装药进行了温度循环条件下的顺序热应力耦合模拟,给出了温度场和应力场,建立了基于应力的累积损伤模型,研究了其累积损伤及主要影响因素。结果表明,温度循环条件下,装药内部产生交变应力,导致损伤累积。温度转换期间累积损伤增长较快,特别是在高温向低温转换期间,影响最大,并且随着升降温速率的增加,累积损伤显著增加。这为准确评估外界环境对固体火箭发动机的影响提供了参考。 相似文献
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近年来变形镁合金得到了广泛的研究和应用,薄板快速铸轧技术为新型变形镁合金提供质量合格的板坯.为了研究铸轧工艺参数对AZ31镁合金薄板快速铸轧过程温度场和热应力场的影响,根据读技术在镁合金中应用的特点基于铸轧区板坯的对称性建立了纵截面1/2的二维几何模型;选择自由网格划分法和Smart-Sizing算法划分有限元网格;采用大型通用有限元分析软件ANSYS对镁合金快速铸轧过程中的铸坯温度场和热-应力场进行了仿真分析,并就不同工艺参数(接触界面换热系数、铸轧速度)对铸坯温度和应力的分布及其相变区的影响进行了研究.仿真结果增强了对镁合金快速铸轧过程相变区温度变化和热裂产生机制的理解,为快速铸轧工艺参数的优化提供了依据. 相似文献
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为了研究工艺参数对AZ31镁合金直接激冷铸造过程温度场和热应力场的影响,根据该技术在镁合金中应用的特点作了一些简化和假设;建立了镁合金铸锭横截面的二维几何模型;建立了基于非稳态热传递的温度场和热弹塑性增量理论的热应力控制方程;根据铸造过程中的传热特点确定了一冷区和二冷区的边界条件和初始条件;采用大型通用有限元分析软件ANSYS对镁合金直接激冷铸造过程中的铸坯温度场和热.应力场进行了仿真分析,并就不同工艺参数(浇注温度)对铸坯温度和应力的分布及其相变区的影响进行了研究.仿真结果增强了对镁合金直接激冷铸造过程热裂产生机制的理解,为直接激冷铸造工艺参数的优化提供了依据. 相似文献
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《系统工程理论与实践》2014,(4)
正August 10-14,2015Beijing,China The International Congress on Industrial and Applied Mathematics(IClAM)is the premier international congress in the field ofapplied mathematics held every four years under the auspices ofthe International Council for Industrial and Applied Mathematics.From August 10 to 14,2015,mathematicians,scientists and entrepreneurs fiom around the world will gather in Beijing,China for the 8th IClAM to be held at 相似文献
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Lü Min 《系统工程与电子技术(英文版)》2008,19(3)
To study the uncertain optimization problems on implementation schedule, time-cost trade-off and quality in enterprise resource planning (ERP) implementation, combined with program evaluation and review technique (PERT), some optimization models are proposed, which include the implementation schedule model, the timecost trade-off model, the quality model, and the implementation time-cost-quality synthetic optimization model. A PERT-embedded genetic algorithm (GA) based on stochastic simulation technique is introduced to the optimization models solution. Finally, an example is presented to show that the models and algorithm are reasonable and effective, which can offer a reliable quantitative decision method for ERP implementation. 相似文献
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A calculus for services innovation 总被引:1,自引:1,他引:0
Innovation in the services area - especially in the electronic services (e-services) domain - can be systematically developed by first considering the strategic drivers and foci, then the tactical principles and enablers, and finally the operational decision attributes, all of which constitute a process or calculus of services innovation. More specifically, there are four customer drivers (i.e., collaboration, customization, integration and adaptation), three business foci (i.e., creation-focused, solution-focused and competition-focused), six business principles (i.e., reconstruct market boundaries, focus on the big picture not numbers, reach beyond existing demand, get strategic sequence right, overcome organizational hurdles and build execution into strategy), eight technical enablers (i.e., software algorithms, automation, telecommunication, collaboration, standardization, customization, organization, and globalization), and six attributes of decision informatics (i.e., decision-driven, information-based, real-time, continuously-adaptive, customer-centric and computationally-intensive). It should be noted that the four customer drivers are all directed at empowering the individual - that is, at recognizing that the individual can, respectively, contribute in a collaborative situation, receive customized or personalized attention, access an integrated system or process, and obtain adaptive real-time or just-in-time input. The developed process or calculus serves to identify the potential white spaces or blue oceans for innovation. In addition to expanding on current innovations in services and related experiences, white spaces are identified for possible future innovations; they include those that can mitigate the unforeseen consequences or abuses of earlier innovations, safeguard our rights to privacy, protect us from the always-on, interconnected world, provide us with an authoritative search engine, and generate a GDP metric that can adequately measure the growing knowledge economy, 相似文献
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为满足卫星有效载荷数据传输系统高速、高可靠性的需求, 提出一种基于L&R(Luise and Reggiannini)算法的高速低复杂度可重构频偏恢复实现方案。为便于算法逻辑架构实现, 对算法的函数功能进行分解及模块化设计; 为减少乘法器资源消耗, 采用复用分解的自相关函数模块; 为提高L&R算法的精度, 对导频段自相关函数进行多段叠加。结果表明, 高速低复杂度可重构频偏恢复实现方案解调性能损失接近为0 dB, 且优化后的算法结构相比于直接结构可减少92.59%的乘法器消耗, 拆分的自相关函数功能模块具有可复用性和重构性。该算法的可工作时钟速率高达370.37 MHz, 在高速接收机中具有极高的应用价值。 相似文献
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论生物系统中的功能不守恒性 总被引:1,自引:0,他引:1
张知彬 《复杂系统与复杂性科学》2004,1(2):43-51
根据能量守恒定律,能量一次转换所做的总功应等于输入的总能量。但在生物系统中,能量的转换是多次的,其总功之和大于系统输入的总能量,此现象称之为功能不守恒性。能量转换效率越高,功能差别越大。能量通过细胞水平的多次转换,总功可提高至2倍左右。能量通过生态系统水平多次转换,总功可提高至1.4倍左右。通过系统内各子系统能流之和称为序能,反映了系统有序性大小,它取决于系统输入总能量和能量转换效率。根据序能原理,用GDP^2/9(GDP为国内生产总值,Q为能量总输入)反映人类社会功能和效率,要比单纯用GDP更客观。绿色GDP应同时考虑使GDP^2/Q增长最大和使自然生态系统的序能最大。人的经济行为和动物的行为对策也符合序能原理。 相似文献
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This paper is about the Wuli, Shili, Renli (WSR) systems methodology. An important concept within this, Renli, has been developed from Confucian philosophy to clarify to Chinese researchers the necessity of dealing with human relations in systems practice. At present, the only formal means of operationalizing Renli that people are exploring in China is to import from the West methods for organizing debate. However, the concept of Renli suggests that more is needed than methods alone. In particular, facilitation skills are required. It is argued that the development of facilitation skills can be enhanced if researchers can gain both theoretical and practical knowledge of group dynamics, and engage in activities of self-reflection to look at, and alter, their own roles in these dynamics and the wider sociopolitical system. There are therefore three aspects to Renli: the use of systems methods for organizing debate, the acquisition of facilitation skills, and self-reflection geared toward the development of facilitation skills and enhanced critical awareness of the politics of intervention. 相似文献
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李弋 《系统工程理论与实践》2011,(Z2):70-74
随着云计算的发展,新的应用不断涌现,但电子邮件服务依然占有着重要的地位.邮件服务器是一种I/O密集的应用.在云计算时代,越来越多的用户邮件保存在服务器端,邮件在从客户端传输到服务器端之前,邮件或者邮件的部分内容在服务器端可能已经存在.基于这种现象,提出了一种方案,通过引入计算的代价来降低通信量,从而提高邮件服务器的处理能力.对电子邮件的格式和SMTP协议进行了扩充,引入了附件和正文分离传输的模式.在邮件传输时,客户端先计算附件的散列值,并作为正文的一部分传输到服务器端,服务器端再根据散列值来判断附件是否需要传输. 相似文献
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金工工艺的优化设计 总被引:2,自引:0,他引:2
邹庆化 《系统工程理论与实践》1996,10(11):106-112
运用价值工程与运筹工程理论, 在金工工艺单项设计指标优化的基础上, 对其设计指标也进行了全面优化。 相似文献