Non-linear finite element models accounting for large displacements have been used to investigate the behavior of steel built-up shear links that had previously been tested using large-scale experiments. The links wer...Non-linear finite element models accounting for large displacements have been used to investigate the behavior of steel built-up shear links that had previously been tested using large-scale experiments. The links were designed using steel grades with yield points ranging from high to low strengths. The objectives of the numerical analyses were to further investigate the non-linear behavior and to correlate the numerical results with experimental observations. Elasto-plastic as well as cyclic stress-strain material properties were incorporated to study the influence of material behavior on the overall shear link response. Non-linear monotonie analyses of the shear links incorporating the cyclic stress-strain steel properties resulted in similar trends in the response as the backbone curves recorded from the physical experiments. The numerical models of built-up shear links utilizing structural grade steels closely correlated to the experimentally recorded shear strength. Models utilizing low yield point steels overestimated the shear strength, which was caused by the characteristics of cyclic behavior of those steels. The detailed numerical models also allowed for investigation of the plastic strain demands on the different components of the link. It was shown that finite element models combined with appropriate stress-strain relationship may be used with confidence to check the design of shear links of different steel grades and sectional geometries.展开更多
Link-up between farmers and supermarket is a new move adopted actively by the current government, conducive to consumers, farmers and circulation enterprises. At present, link-up between farmers and supermarket is lau...Link-up between farmers and supermarket is a new move adopted actively by the current government, conducive to consumers, farmers and circulation enterprises. At present, link-up between farmers and supermarket is launched in China's 15 provinces and cities, which will set off the revolution in the field of agricultural circulation. Based on the current situation of link-up between farmers and supermarket and the existing problems, we put forth the following recommendations: promoting the quality of farmers' cooperative organizations; establishing the logistics center of fresh agricultural products; using economies of scale to reduce the fresh logistics costs; improving the operation and management level of fresh agricultural products in supermarket.展开更多
随着不间断电源(Uninterruptible Power Supply,UPS)系统在广播电视节目播出系统中的应用需求增大,通过优化UPS供电模式和设计UPS智能电源监测系统,在实现自主运行、智慧运维的基础上,提高广播电视UPS系统的稳定度控制精度和工作效率,...随着不间断电源(Uninterruptible Power Supply,UPS)系统在广播电视节目播出系统中的应用需求增大,通过优化UPS供电模式和设计UPS智能电源监测系统,在实现自主运行、智慧运维的基础上,提高广播电视UPS系统的稳定度控制精度和工作效率,同时降低其自身的故障率。展开更多
基金the Federal Highway Administration through the Highway Project at the Multidisciplinary Center for Earthquake Engineering Researchthe toll bridge retrofit program of the California Department of Transportation through the University of California,San Diego
文摘Non-linear finite element models accounting for large displacements have been used to investigate the behavior of steel built-up shear links that had previously been tested using large-scale experiments. The links were designed using steel grades with yield points ranging from high to low strengths. The objectives of the numerical analyses were to further investigate the non-linear behavior and to correlate the numerical results with experimental observations. Elasto-plastic as well as cyclic stress-strain material properties were incorporated to study the influence of material behavior on the overall shear link response. Non-linear monotonie analyses of the shear links incorporating the cyclic stress-strain steel properties resulted in similar trends in the response as the backbone curves recorded from the physical experiments. The numerical models of built-up shear links utilizing structural grade steels closely correlated to the experimentally recorded shear strength. Models utilizing low yield point steels overestimated the shear strength, which was caused by the characteristics of cyclic behavior of those steels. The detailed numerical models also allowed for investigation of the plastic strain demands on the different components of the link. It was shown that finite element models combined with appropriate stress-strain relationship may be used with confidence to check the design of shear links of different steel grades and sectional geometries.
基金Supported by Humanities and Social Sciences Youth Project of theMinistry of Education in 2010 (10YJC790234)
文摘Link-up between farmers and supermarket is a new move adopted actively by the current government, conducive to consumers, farmers and circulation enterprises. At present, link-up between farmers and supermarket is launched in China's 15 provinces and cities, which will set off the revolution in the field of agricultural circulation. Based on the current situation of link-up between farmers and supermarket and the existing problems, we put forth the following recommendations: promoting the quality of farmers' cooperative organizations; establishing the logistics center of fresh agricultural products; using economies of scale to reduce the fresh logistics costs; improving the operation and management level of fresh agricultural products in supermarket.
