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排序方式: 共有436条查询结果,搜索用时 15 毫秒
21.
Naoya Umeda Akihiko Matsuda Masami Hamamoto Shiro Suzuki 《Journal of Marine Science and Technology》1999,4(2):45-57
A systematic method for assessing intact ship stability with a free-running model in a seakeeping and maneuvering basin is
proposed in this paper. Model experiments were carried out in extremely steep regular waves for a model drifting, running
in head seas, and quartering seas. This method was applied to two purse seiners, and efficiently identified thresholds in
metacentric heights for capsizing of these ships. These capsizing thresholds are compared with requirements of the IMO Code
on Intact Stability. This series of model experiments also confirms that capsizing at the threshold occurs only in quartering
seas, and shows that capsizing is caused by broaching, loss of stability on a wave crest, or bow diving.
Received for publication on Jan. 20, 1999; accepted on July 6, 1999 相似文献
22.
Naoya Umeda 《Journal of Marine Science and Technology》1999,4(1):16-26
To provide a theoretical methodology to predict the critical condition for capsizing due to broaching, a nonlinear dynamical
system approach was applied to the surge–sway–yaw–roll motion of a ship running with an autopilot in following and quartering
seas. Fixed points of a mathematical model for the ship motion and unstable manifolds of the fixed point near the wave crest
were systematically investigated. As a result, the existence of heteroclinic bifurcation was identified. With numerical experiments,
it was confirmed that this heteroclinic bifurcation reasonably well represents the critical condition for capsizing due to
broaching. Thus the nonlinear dynamical approach can be substituted for tedious numerical experiments.
Received for publication on Nov. 20, 1998; accepted on March 16, 1999 相似文献
23.
24.
《铁道标准设计通讯》2016,(5):149-151
地下固定式架车机组是地铁车辆段的关键设备,介绍地下固定式架车机组的功能及组成,分析该设备在地铁车辆段土建及各系统设计时与各专业的接口,并提出设计时各专业间的设备界面划分,论述地下固定式架车机组的包容性设计,保证其施工图设计的顺利开展。 相似文献
25.
本文在对斯太尔重型汽车的双轴转向传动机构进行分析的基础上建立了数学模型,研究了各部分的传动过程,并采用MATLAB语言编写了转向传动机构分析程序,对转向轴内外轮之间,前后轮间的转角匹配,以及最小转弯半径的匹配关系进行了优化。 相似文献
26.
Svein Ivar Sagatun Kjell Herfjord Finn Gunnar Nielsen Erling Huse 《Journal of Marine Science and Technology》1999,4(2):58-67
One of the main challenges in estimating impact energy in collisions between marine risers is the assessment of the riser
mass involved in the collision. Evidently the entire riser mass does not contribute to the collision. Hence, the question
is: What is the equivalent riser mass which contributes to the impact energy? This article presents three different ways of
estimating the riser mass participating in the collision energy. The first method is strictly experimental. The second method
uses a numerical experiment together with system identification techniques. The third method is a strictly analytical method,
which results in an asymptotically upper bounded estimate of the participating mass. Two risers are examined as case studies.
The first riser is a 1 : 100 model scale riser used in collision experiments carried out at Marintek's towing tank in Trondheim,
Norway. The second case uses a real world riser in use on the Troll B oil production platform operating in the North Sea.
The proposed methods yield consistent and comparable results.
Received for publication on Feb. 1, 1999; accepted on July 8, 1999 相似文献
27.
28.
Takashi Tsubogo 《Journal of Marine Science and Technology》1999,4(2):76-83
This paper deals with the dispersion relation of hydroelastic waves in pontoon-type very large floating structures (VLFS)
using a simple beam modeling, where the term hydroelastic waves means propagation of deflection vibrations in VLFS. The purpose of this paper is to show the properties of the hydroelastic
waves. The dispersion relation of hydroelastic waves propagating in an infinite plate floating on the water is derived based
on the linear water wave theory. The effects of the water depth and of the bending rigidity of the floating plate on the wavelength,
phase velocity, and group velocity of the hydroelastic waves are shown theoretically or numerically. Then, the dispersion
relation of hydroelastic waves in a finite plate floating on shallow water is investigated. It is shown that the wavelength
or the phase velocity of the hydroelastic waves varies with the location in the plate.
Received for publication on April 7, 1999; accepted on Aug. 20, 1999 相似文献
29.
Tsong-Neng Wu Jenhwa Guo Yih-Nan Chen Wen-Ching Chen 《Journal of Marine Science and Technology》1999,4(3):117-122
We have investigated the usefulness of active stabilizing fins to reduce ship pitching under varying forward speeds, and
in varying wave lengths. A 4-m self-propelled model ship and an electrohydraulically driven stabilizing fin system were used
in our experiment. Pitch angles, pitch rates, and ship forward speeds were measured and fed back to a controller to calculate
the deflection angle of the stabilizing fin. The effects of fin nonlinearity on achievable pitch reduction performance are
discussed. It is shown that the desired pitch response can only be achieved when the fin is operated in the linear region.
The overall dynamic response of the ship approaches open-loop behavior when the degree of nonlinearity is high. This simple
analysis of the pitch stablizing system provides basic information to ship designers. Experimental results validate these
design guidelines.
Received for publication on Feb. 12, 1998; accepted on Dec. 8, 1999 相似文献
30.
建立了小半径曲线桥上"轨道-梁-墩"一体化计算模型,分析其在温度变化和离心力作用下联合板位移以及侧向挡块的受力情况,对曲线半径、侧向挡块弹性垫板刚度和侧向挡块间距的影响规律进行了分析。通过对侧向挡块进行结构强度检算,认为侧向挡块具有较高的安全储备量。 相似文献