Upgrading the National Geotechnical Centrifuge

升级国家土力离心机

• 批准号: 8714727
• 负责人: Bruce Kutter
• 金额: $ 29.9万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-04-15 至 1990-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8714727&HistoricalAwards=false
• 关键词: Upgrading; National; Geotechnical; Centrifuge

This action is to provide funds for the construction of an enclosure to the National Geotechnical Centrifuge. Centrifuge modeling is a useful tool for studying a wide variety of geotechnical earthquake engineering problems. The state of stress and strain in an earth structure is dependent upon the overburden pressure, which is analogous to the hydrostatic pressure which increases with depth in a body of water. This overburden pressure is a result of gravitational loading. When testing a scale model of an earth structure, this gravitational loading must be correctly scaled, and this requires that gravity be increased in proportion to the reduction in the scale of the model: a half-scale model has to be subjected to twice the normal gravity loading. This increase in gravity loading can be obtained by testing the scale model in a centrifuge. The National Geotechnical Centrifuge was donated by NASA AMES to the University of California at Davis. It has been converted for use as a geotechnical engineering centrifuge, and more recently it was moved to the Davis campus. It is now operational at the new location, but funds were not available to provide a roof for the enclosure. As a result, the centrifuge is operating in the open air, which severely limits the capacity of the machine due to windage losses: as the arm turns it acts as a large centrifugal fan. These windage losses are unavoidable, but they can be reduced significantly by appropriate design of the enclosure. For the National Geotechnical Centrifuge, the open pit installation performance can be increased from 100 g-tons to 500 g-tons by installing a suitably designed enclosure. The increased performance provides a capacity which is sorely needed in the United States. Researchers needing this capacity must currently perform their tests on a centrifuge in Cambridge, England. This is both costly and slow. The construction of an enclosure for the National Geotechnical Centrifuge will provide a facility that will increase dramatically the experiments that can be performed in geotechnical engineering, in particular in earthquake engineering.

该行动旨在为国家岩土离心机外壳的建设提供资金。 离心机建模是研究各种岩土地震工程问题的有用工具。地球结构中的应力和应变状态取决于上覆压力，这类似于随着水体深度而增加的静水压力。该覆盖压力是重力载荷的结果。在测试地球结构的比例模型时，必须正确缩放重力载荷，这要求重力与模型比例的减小成比例地增加：半比例模型必须承受正常尺寸的两倍重力加载。重力载荷的增加可以通过在离心机中测试比例模型来获得。 国家岩土工程离心机由 NASA AMES 捐赠给加州大学戴维斯分校。它已被改装用作岩土工程离心机，最近被转移到戴维斯校区。它现已在新地点投入使用，但没有资金为围栏提供屋顶。因此，离心机在露天运行，由于风阻损失，这严重限制了机器的容量：当臂转动时，它充当大型离心风扇。这些风阻损失是不可避免的，但可以通过适当的外壳设计来显着减少。对于国家土工离心机，通过安装适当设计的外壳，露天安装性能可以从 100 克吨增加到 500 克吨。性能的提高提供了美国急需的容量。需要这种能力的研究人员目前必须在英国剑桥的一台离心机上进行测试。这既昂贵又缓慢。 国家岩土离心机外壳的建造将提供一个设施，该设施将大大增加岩土工程，特别是地震工程中可进行的实验。