粉末冶金件表面滚压塑性变形强化过程的数值模拟

针对粉末冶金件的表面滚压强化工艺,结合粉末冶金材料的塑性理论,运用MSC.Marc有限元软件,通过正确建立有限元模型,比较分析了不同进给量、滚压转速和摩擦系数对相对密度分布的影响及变化规律.结果表明,表面滚压可以有效提高粉末冶金件的表面区密度.适当提高进给量、滚压转速和摩擦系数,将有利于相对密度的提高.在工艺设计中应按实际加工条件和保证表面质量的前提下,适当选择这些工艺参数.同时,所述建模与模拟方法为粉末冶金材料的数值模拟提供了一种合理的研究思路.     

咬入角对板材热轧成形影响的有限元模拟

咬入角是影响坯料能否正常被轧辊咬入并轧制出优质板材的重要因素。采用有限元分析软件MSC.Marc模拟了四辊可逆式轧机进行板材热轧的过程,分析了不同情况下咬入角对轧制力、应变场、应力场分布的影响,并反映了轧制过程中的塑性变形规律。结果表明,模拟结果与实际相符,且在合理的角度范围内,改变压下量时19.87°的咬入角和改变半径时18.1°的咬入角应力应变分布比较均匀,板材成形质量较好。     

Kalsi型流体动压密封结构及其接触性质研究

流体动压径向密封是利用流体动压效应研制的新型径向动密封结构, 其典型产品Kalsi型流体动压密封已在国外石油机械中获得了成功应用。在分析该密封结构和机理的基础上, 提出了“软弹流”数值迭代研究方法, 并采用MSC Marc软件对影响密封性能的重要因素———轴向接触压力进行了分析, 探讨了结构、材料、初装配条件在Kalsi密封应用中的作用, 为深入开展理论研究和进行密封圈的研制奠定了基础。     

深厚软土层中搅拌桩有效桩长分析

用有限元Marc软件对在深厚淤泥层中用搅拌桩进行地基处理的工程情况进行了模拟,探讨了在搅拌桩桩端未到达较硬土层时的有效桩长,并得出了一些可以指导工程实践的有用结论.     

Everything We Need: Scarcity,Scale, Hyperobjects

Scarcity as a concept places an emphasis on limits and the restrictions that there might be on the supply of resources, energy and materials. Timothy Morton, who is Professor of English at the University of California, Davis, and has written extensively on philosophy and ecology, among other subjects, questions philosophically this emphasis on limits and the contemporary tendency to need to quantify everything around us. He urges us to ‘look beyond those artificial boundaries’ and ‘find abundance’.     

Camouflage as Aesthetic Sustainability

A textile approach to architecture offers unique opportunities to explore a structure's surface and texture. Through a discussion of the history of the technique of camouflage and her own projects with Design Research and Development (DR_D), Dagmar Richter demonstrates the potential for surface enrichment to exceed mere ornament or patterning. A ‘performative texture’, camouflage interacts with its context mimicking the natural and effectively disguising whatever it covers. With a now long military association, camouflage also provides anything but a neutral background for its cover. Copyright © 2006 John Wiley & Sons, Ltd.     

基于FEA的蜂窝铝芯平压分析

利用非线性有限元分析软件MSC.Marc对蜂窝铝芯平压过程进行了模拟计算,得到了应力分布图和应力沿路径分布曲线,结合图形和曲线分析了蜂窝铝芯的应力分布规律和变形特点。结果表明,平压过程中应力集中出现在交棱处,在外力作用下这些位置最容易发生失稳,而面板中间的应力值始终相对交棱处应力值较小;由于交棱和壁板中部受到的约束不同,最大应力分布区域与变形最大区域不一致。     

Space is an Ecology for Living In

Current space exploration can be viewed as an augmentation of the activities of the 20th century, albeit with a greater emphasis on new technologies and privatisation. With the continuation of this trend, could outer space be in danger of becoming a vast territory exposed to the voracity of would-be prospectors, manned by robots? Rachel Armstrong , Professor of Experimental Architecture at Newcastle University and guest-editor of the April 2000 AD Space Architecture issue, advocates a much more far-reaching biological definition of Space, driven by a concern for the natural environment, that emphasises its potential as an ecology for living in.