共查询到18条相似文献,搜索用时 249 毫秒
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在结构轻量化需求日益增长的背景下,轻质高强度金属板材被广泛用于汽车制造、航空航天等领域。金属板材在成形中是否会发生破裂失效,是冲压工艺设计最为关注的指标点。材料的破坏与其在大变形过程中的损伤演化有关,从宏观角度来看,材料的损伤可通过模量衰减进行描述。综合采用拟流动角点理论和GTN损伤模型,对高强度硼钢22MnB5的变形行为进行了仿真研究。分别采用GTN损伤模型、拟流动角点理论结合GTN损伤模型、经典Mises本构模型得到样件拉伸曲线,开展对比研究,分析了拟流动角点理论对破裂预测结果的影响,表明拟流动角点理论充分考虑了材料在变形中的模量弱化效应。进一步,开展样件在多应力状态下的半球胀形实验与仿真预测,印证了该方法对板材变形特征与破裂预测的适用性,对金属板材成形工艺的优化改进具有指导意义。 相似文献
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针对工业机器人是一个复杂的非线性■强耦合■多变量的动态系统,提出了CMAC与非线性PID复合控制器设计。该控制器由非线性PID反馈和CMAC前馈2部分构成,可消除初始输出力矩过大的弊端。采用非线性PID控制器替代经典PID控制器,因非线性积分环节可以随误差的变化进行调整,从而可以提高其自适应性和鲁棒性。CMAC学习速度快,网络收敛所需的训练次数少,可有效地用于机器人实时在线控制。仿真结果表明该设计方法具有有效性和可行性。 相似文献
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This paper introduces a knowledge-based view of the firm, which enables us to analyze how the firm should build up its technology strategies in order to capture profits from knowledge assets through knowledge creation, replication, integration and transfer. The basic idea is to shed light on the mechanisms that make it possible, first, to create value from knowledge assets, second, to protect the value created by using different protection mechanisms (such as legal means or tacitness) and, third, to share the value created between the innovator, imitators and partners (open innovation model). In our model we derive technology strategies based on different knowledge bases and their characteristics. By means of our simulation experiments we open up some black boxes behind technology strategies that are often launched only as empirical generalizations, such as Freeman’s famous technology strategy typology. Our tool can also be used as a framework when the dynamic effects of technology strategies are traced and empirically scrutinized. 相似文献
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Industrial high-tech markets are characterized by profound levels of market and technological uncertainty and so firms herein must navigate extraordinarily dynamic and fast-moving environments. In such settings, traditional top-down modes of strategic planning are ill-suited to generate the flexibility and speed of change necessary for firms to maintain environmental fitness over time. Survival requires that significant decision-making powers necessarily be located on the operational periphery of the firm. To understand how the resultant multiplicity of micro-strategizing and decision-making might engender macro-level change(s) to business models, we conduct a cross-sectional case study of two business models at Cisco Systems. After problematizing two broad strands of extant theory, we conjecture that a rival theory – complexity theory – might allow us to better explain how Cisco's business models evolve in practice and we utilize our case study to test this conjecture. We find that the business models studied have the capacity to change themselves spontaneously and autonomously from executive-led decisions in response to external stimuli. We offer a novel theoretical insight by postulating the existence of complex adaptive business models and we advance knowledge in a way that is useful for practitioners by suggesting they perceive themselves as facilitators and orchestrators of business models rather than owners or even controllers of them. 相似文献
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供热系统完成初调节后,某支路热用户会因热量需求改变而发生流量改变,从而影响供热效果。为了满足此热用户的供热需求,又不影响其他热用户的供热需求,根据实际运行数据建立换热站二次管网循环泵电动机的功耗模型,模型的主要约束条件为各支路电动调节阀的开度、各支路水力平衡态,利用遗传算法的寻优能力,通过引入惩罚函数,将约束问题转化为无约束问题,以供热系统上所有支路热用户的供热平衡为最终目标进行寻优仿真。仿真结果表明,在满足所有支路热用户的供热平衡时,确保了循环泵电动机的运行功耗最小,得到了各电动调节阀的开度设置,节约热负荷约7.6%。所用方法有效地改善了热用户的供热需求,可为进一步深入研究二次网支路热用户的供热平衡提供参考。 相似文献
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企业集团规制政策:德隆危机的反思 总被引:3,自引:0,他引:3
本文在反思德隆危机的基础上,探讨了企业集团的特性、不当市场行为及其根源。认为企业集团具有“企业”与“市场”双重属性,这一本质属性决定了在企业集团内部企业间边界模糊。企业间边界模糊容易滋生转移定价、逃废债务、操纵股市等不当市场行为。而企业间边界模糊与市场势力相结合更容易导致企业集团产生垄断行为。企业集团规制政策需要从企业集团的特性及不当行为产生的根源入手。 相似文献