栓钉锈蚀与抗剪承载力试验研究

栓钉剪力连接件是保证钢梁与混凝土翼缘共同工作的关键元件,栓钉锈蚀后将直接影响组合梁的抗剪连接程度,进而影响梁的承载能力.文中将通过推出试验,研究栓钉锈蚀对其承载力的影响规律.通过对试验结果的回归分析,研究栓钉锈蚀后的抗剪承载力的计算公式.     

波浪在珊瑚礁坪上传播的水槽试验研究

为研究波浪在珊瑚礁上的传播规律,分析波浪传至礁缘后破碎及传播情况,为设计波要素的确定提供参考依据。试验模拟了常年平均波浪和重现期50 a两种波浪条件。试验结果表明:波浪沿传播方向在礁坪边缘附近破碎后继续向坪内传播,并达到波面稳定状态,礁坪上的波浪传播特性表现为礁缘处波浪易破碎和礁坪上波浪衰减较快;波浪破碎表现为行进波破碎,且小于波浪在一般缓坡地形上的破碎指标,破碎波高水深比(Hb/d)约为0.5附近,重现期50 a大浪时礁缘处最大可达0.76。     

单人常压潜水装具躯体结构的多目标优化设计

文章采用基于响应面（RSM）近似模型和多目标遗传算法（MOGA）对新型单人常压潜水装具躯体结构进行多目标优化设计。首先建立躯体的结构优化模型,分析设计变量对设计目标的影响。通过试验设计（DOE）得到设计目标的响应特征,拟合建立响应面近似模型,最后采用遗传算法对响应面模型进行多目标优化求解,得到躯体结构的优化设计方案。     

有护面块体掩护的斜坡堤弧形胸墙波压力研究

弧形胸墙可以有效减小斜坡堤越浪、降低胸墙顶高程,因此越来越多地在工程中采用。但在规范中对斜坡式防波堤弧形胸墙波压力计算方法没有明确规定。结合工程实例,将弧形胸墙波压力物理模型实测结果与现行规范直立胸墙波压力计算结果进行对比分析,总结了该工程防波堤弧形胸墙在有掩护条件下所受的波压力情况,供工程设计参考。     

Intermodal land transportation systems and port choice,an analysis of stated choices among shippers in the Rhine–Scheldt delta

ABSTRACT

In this paper, the research concentrates on the intermodal land transportation systems which link Antwerp and Rotterdam with a shared hinterland in the long and medium distance range. It uses a choice-based experiment which has been calibrated on the basis of real case studies to understand shipper’s choices between end-to-end chains. The stated choices reveal shippers’ preferences when needing to choose between two logistic pathways, which employ a similar multimodal composition of transport modes to bring the container from door-to-door, but which route the container differently through alternative maritime gateways. The study therefore touches upon the topic of port competition applying a value-driven supply chain approach. Despite narrow differences on the main performance criteria of the door-to-door chains, the empirical analysis proves that shippers are not loyal to one of the ports, but give preference to the lowest cost solution. Enhancing the frequency levels of the inland transportation solution is only at the benefit of the more costly chain. The findings reiterate the importance of intermodal land transport systems in the competition between load centres.     

Random regret minimization or random utility maximization: an exploratory analysis in the context of automobile fuel choice

Interest in alternative behavioural paradigms to random utility maximization (RUM) has existed ever since the dominance of the RUM formulation. One alternative is known as random regret minimization (RRM), which suggests that when choosing between alternatives, decision makers aim to minimize anticipated regret. Although the idea of regret is not new, its incorporation into the same discrete choice framework of RUM is very recent. This paper is the first to apply the RRM‐model framework to model choice amongst durable goods. Specifically, we estimate and compare the RRM and RUM models in a stated choice context of choosing amongst vehicles fuelled with petrol, diesel and hybrid (associated with specific levels of fuel efficiency and engine capacity). The RRM model is found to achieve a marginally better fit (using a non‐nested test of differences) than its equally parsimonious RUM counterpart. As a second contribution, we derive a formulation for regret‐based elasticities and compare utility‐based and regret‐based elasticities in the context of stated vehicle type choices. We find that in the context of our choice data, mean estimates of elasticities are different for many of the attributes and alternatives. Copyright © 2011 John Wiley & Sons, Ltd.     

两款白车身试验模态分析与比较

为提高某新型卡车白车身振动特性,改善车身的耐久性与舒适性,通过具体模态试验,获得并分析了该轻卡白车身模态试验数据。根据与该车型相匹配的部件振动参数,并参考相同平台的某型客车振动参数,提出了该新型卡车白车身改进方案。同时介绍了模态试验系统的组成和流程,探讨了试验测系统、模态数据可靠性检验的一般方法。     

自锚式悬索桥抗震性能试验研究

通过模型振动台试验研究了自锚式悬索桥的抗震性能。以一座自锚式悬索桥为原型,根据相似比设计模型并进行了振动台试验。对试验得到的动力特性、阻尼比及输入安评波的地震反应进行了分析,并用有限元的结果和试验结果进行了校核,总结了自锚式悬索桥的抗震性能,为今后相关的工程项目提供参考。     

基于正交设计的隧道Ⅴ级围岩相似材料配比试验研究

基于正交设计方法,将雅沪高速公路某隧道围岩的粘聚力和摩擦角作为研究目标,使用粉煤灰、干河沙和机油作为原料进行拌和,较好地模拟了V级围岩。通过大量试验,确定相似材料物理参数的影响因素并进行敏感性分析,最终确定材料的合理配比,为下一步的试验研究做好准备。     

ZGMn13钻削刀具断屑排屑实验研究

针对ZGMn13刀具钻削过程中断屑、排屑困难的问题,从刀片材料、刀片结构、刀片与刀杆连接方式三个方面进行了改进.通过实验验证,改进后的刀具在加工中不仅断屑、排屑效果理想,而且较旧刀具使用寿命提高了34.7％,能降低生产成本,得到了良好的优化效果.