排序方式: 共有41条查询结果,搜索用时 15 毫秒
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Ching-Chih Chang Chih-Min Wang 《Transportation Research Part D: Transport and Environment》2012,17(3):185-189
The paper evaluates the effectiveness of strategies designed to reduce these pollutants in port areas, based on a newly developed assessment model to calculate emissions. The case study found that the strategy of reducing the ship’s speed to 12 knots is most effective in cutting fuel consumption and costs, as well as emissions. Adopting an onshore power supply system could reduce CO2 emission by 57.16% and PM by 39.4%. By adopting the strategies of both reduced speed and cold ironing emissions control, a reduction in emissions of 71% to 91% can be achieved with a 20 nautical mile reduced speed zone. Therefore, the goals of reductions in emissions to improve port areas air quality could be achieved through adopting a green port policy in the future. 相似文献
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《铁道标准设计通讯》2016,(1):23-26
针对传统T型轨检小车走行轮采用外圆环贴合轨道侧面的设计,存在制造与后期维护繁琐、单双轮组件的走行轮不能互换、长时间使用磨损大的问题,提出一种新型的走行轮改进机构,该机构采用3个规格完全一样的走行轮,并设计一定位轮装置代替双轮组件走行轮外圆环的设计,显著提升走行轮在制造与后期维护的简便性以及耐磨性能。通过对定位轮装置中心轴的ANSYS Workbench有限元分析,验证该装置结构设计的合理性。 相似文献
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车辆荷载对基坑支护结构的影响分析 总被引:1,自引:0,他引:1
《铁道标准设计通讯》2015,(8):122-126
为了研究车辆荷载对基坑支护结构体系的影响,针对常规等效代换土层厚度法未考虑破裂棱体破裂角变化问题,引入改进等效代换土层厚度法,依据库伦土压力理论,计算破裂棱体自重,结合破裂棱体平衡关系式,循环迭代得到破裂角收敛值,根据此破裂角换算得到新的土层厚度。基于地铁车站基坑工程,通过数值模拟,采用常规方法和改进的等效代换土层厚度法研究车辆荷载对基坑支护结构的影响,分别得到支护结构的水平位移曲线。研究表明,破裂角变化会引起代换土层厚度变化,从而影响计算精度;在基坑支护结构设计中,采用改进等效代换土层厚度法来考虑车辆荷载影响是可行的。 相似文献
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结构系统的可靠性评估是结构设计的一个重要研究内容,而极限状态函数的建立是进行可靠性评估的基础.但是,大型结构系统的极限状态函数极为复杂,响应面法用简单的多项式进行模拟的精度较低,导致误差较大.文章提出用神经网络替代多项式来拟合复杂的极限状态函数,形成所谓的神经网络响应面.然后,基于塑性极限理论,文中提出了不依赖于失效模式的极限状态函数表达形式及采用ICP对该极限状态函数进行计算的方法.最后,依照拟合得到的神经网络响应面,给出了大型结构系统失效概率的方法.通过两个算例计算并和其它方法进行比较,表明该方法的计算精度较高,而计算时间大大降低. 相似文献
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堆载预压是处理软弱地基的一种有效方法,可以加快软弱地基的固结沉降。为了研究在明洞回填土地段采用堆载预压加快固结沉降的可行性,以京张高铁东花园隧道为工程背景,通过有限元软件对结构覆土进行验算,得出不同衬砌类型明洞所能承受的最大覆土厚度,利用改进高木俊介法对明洞回填土堆载预压进行计算,得出不同堆载高度下回填土的固结度。研究结果表明:(1)在堆载条件下,回填土的固结度随着覆土厚度的增大而呈幂函数形式减小,且固结度受堆载高度的影响不大。(2)在相同的覆土条件下,堆载高度对保留土高度影响较小;(3)堆载预压可以加快明洞回填土的固结沉降,是一个比较可行的方案。 相似文献
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文章以改进后的鑫兴10甲板货船为例,对增加了两个舱后的船体进行总纵强度分析。在进行强度分析过程中,首先采用澳大利亚的Maxsurf软件计算不同工况下的静水弯矩。进而把静水弯矩施加到该船的货舱区域,同时利用有限元分析软件MSC.Nastran进行强度校核,得到了总纵强度的计算步骤和结论,同时保证了鑫兴10甲板货船建造的顺利完成。 相似文献
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The paper focuses on the ultimate strength of perforated platings with circular openings and manholes, eventually reinforced by ringed or carling stiffeners, in order to develop a comprehensive and rationale format, useful to assess the ultimate capacity of perforated plate panels under uniaxial compression. In this respect, a large number of FE simulations is performed by Ansys Mechanical APDL, in order to provide new design formulas for the ultimate strength of platings with circular openings or manholes and, subsequently, for perforated plate panels reinforced by local stiffeners. The design formulas are developed by properly varying the opening size and the scantlings of ringed or carling stiffeners, in order to provide a comprehensive set of design curves. Hence, the incidence of the opening longitudinal position on the ultimate capacity of perforated platings, without and with local stiffeners, is also investigated. Finally, the proposed equations are applied in a straightforward design example. Based on current results, the new design formulas allow a reliable assessment of the ultimate capacity of platings with circular openings or manholes and the incidence of local stiffeners on the plating ultimate strength, so providing a rationale design format that could be easily embodied in current Rules and guidelines. 相似文献