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171.
为评价市域快轨的减振效果,以成都市域快轨 18 号线某圆形盾构隧道为例,选取了线路条件基本相同的相近断面,对双层非线性减振扣件、减振垫浮置板、钢弹簧浮置板 3 种减振措施及对应普通道床断面进行现场测试,研究市域快轨减振措施的减振效果。通过对实测数据进行时域、频域和 1/3 倍频程分析,得到不同减振措施和普通断面的隧道壁最大 Z 振级(VLZmax),并对比得到不同减振措施的减振效果;通过对测点的隧道壁振动加速度级及地面振动进行 1/3 倍频程分析,得到振动的传播衰减情况。结果表明:3 种减振措施都有减振效果,双层非线性减振扣件减振效果为 7.3 dB,减振垫浮置板的减振效果为 16.2 dB,钢弹簧浮置板的减振效果最好,达到了19.7 dB。 相似文献
172.
本模型揭示公路隧道火灾期间发生逆流时火源区域烟流流动规律,得出公式可用于估算阻止火灾期间发生逆流时所需的“临界风速”。从本模型得知临界风速取决于隧道高度和火源热释放率的大小。通过与原型试验隧道火灾试验数据进行比较,本模型可以为防灾通风设计提供依据。 相似文献
173.
In case of a submerged floating tunnel (SFT), which is difficult to cast in-site underwater construction, it is modularized on land and then assembled them in the field. Therefore, it is influential to investigate the structural performance of the joints between the modules. A concept of the steel-concrete composite hollow in the SFT, which stably maintains the joints, has been proposed by applying prestressing method to resist various external loads. In this study, the bending behavior of module joints was experimentally analyzed to evaluate the safety for the bending deformation that is dominant in SFT. Test results show that there is a difference at the module joint portion in the performance depending on whether or not the inner steel tube is connected. The bending stiffness of the module joints in the SFT was very similar but there was a difference in strength. The maximum strength was increased from 700 kN to 1200 kN when the inner tube was connected, and the residual displacement was increased from 15 mm to 40 mm. As a result, in the design of the module joint, depending on the purpose of SFT, it is possible to consider both methods which is allowing the ductility behavior of internal tube and controlling the tight connection. Moreover, the failure criterion of the bending behavior of the module joint can be selected as the maximum load or deformation limit. 相似文献
174.
In the past several decades, extensive investigations have been carried out on the hydroelastic responses of Very Large Floating Structures (VLFS) in the deep open sea by researchers around the world. However, when tackling the hydroelastic problems of VLFS used as the protection and exploitation of marine resources near offshore and islands, the effects of complex environments, such as the seabed profile and inhomogeneous wave conditions should be taken into account. Based on the development history of VLFS and the process of classical hydroelasticity of VLFS, the research results of hydroelastic responses of VLFS in complex environments have been systematically summarized in this paper, so as to provide a basis for the further research. 相似文献
175.
176.
赵文春欧阳剑锋刘胜道文昊东 《中国舰船研究》2022,(6):182-186
[目的]为了获得舰船上方不同高度平面磁场数据,解决舰船上方拱顶磁场推算到平面磁场的问题,提出用面磁荷法进行舰船上方的磁场推算。[方法]从等效源理论出发,利用拱顶磁场数据进行反演建模,将舰船磁场等效为面磁荷产生的磁场,用面磁荷正演舰船上方的磁场。将面磁荷法推算出的磁场与舰船实际磁场进行对比,验证面磁荷法的可行性。[结果]通过数值仿真计算,舰船磁场垂直分量推算的相对均方根误差为0.44%;利用磁性船模进行实验分析,磁场垂直分量推算的相对均方根误差为7.64%。[结论]仿真和船模实验分析表明,利用面磁荷法进行磁场推算,其推算值与测量值较为吻合,推算的相对均方根误差较小,具有较高的精度,可用于实际工程计算。 相似文献
177.
Reduction of greenhouse gas emission and fuel consumption as one of the main goals of automotive industry leading to the development hybrid vehicles. The objective of this paper is to investigate the energy management system and control strategies effect on fuel consumption, air pollution and performance of hybrid vehicles in various driving cycles. In order to simulate the hybrid vehicle, the combined feedback–feedforward architecture of the power-split hybrid electric vehicle based on Toyota Prius configuration is modeled, together with necessary dynamic features of subsystem or components in ADVISOR. Multi input fuzzy logic controller developed for energy management controller to improve the fuel economy of a power-split hybrid electric vehicle with contrast to conventional Toyota Prius Hybrid rule-based controller. Then, effects of battery’s initial state of charge, driving cycles and road grade investigated on hybrid vehicle performance to evaluate fuel consumption and pollution emissions. The simulation results represent the effectiveness and applicability of the proposed control strategy. Also, results indicate that proposed controller is reduced fuel consumption in real and modal driving cycles about 21% and 6% respectively. 相似文献
178.
Stress evaluation of a submerged floating tunnel (SFT) is an issue important for determining the section dimensions required to resist environmental loads. However, the complex interaction between an SFT and surrounding fluid has confined most research on SFTs to longitudinal global time-history analyses based on Morison's equation [1]. Even though these analyses give sufficient information in the longitudinal direction, too little information about the circumferential direction compels an SFT section to be designed conservatively. This means that SFT design requires additional information on the structural behavior of the tunnel in the circumferential direction for efficient design. Accordingly, a supplementary approach by which to obtain structural responses in the circumferential direction is introduced in this paper. Upon consideration of the static responses equivalent to the dynamic behavior, three-dimensional (3-D) finite-element analyses of an SFT were performed by application of static loads corresponding to dynamic loads equivalent to those of wave, current and earthquake. The validation of each equivalent static load was supported by the results from comparison of the tension forces in mooring lines obtained using OrcaFlex [2] and ABAQUS [3]. These were used mainly for longitudinal dynamic analysis and 3-D stress evaluation, respectively, of an SFT. Based on the stresses obtained in the longitudinal and circumferential directions, the selection of suitable section dimensions for an SFT is considered. 相似文献
179.
180.
通过装备某型船的浮筏,以及对双层隔振装置陆上隔振效果配机试验的测试结果和大量数据进行分析,得到了一些有意义的结果,总结出了一些规律,这些规律对于指导、改进浮筏设计具有较强的实用价值。提出了浮筏优化设计目标、考虑因素以及设计程序。 相似文献