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1.
Yoshiki Nishi Kentaroh Kokubun Kunihiro Hoshino Shotaro Uto 《Journal of Marine Science and Technology》2009,14(3):285-295
Vortex-induced vibrations of a rigid circular cylinder were studied by constructing a theory based on a wake oscillator model
under quasisteady approximations, thereby evaluating vortex-induced hydrodynamic forces acting on the cylinder. A lock-in
limit line representing the boundary for the occurrence of frequency lock-in was also theoretically derived. Hydrodynamic
forces in forced oscillation problems estimated by the theory were compared with measured ones. Although some discrepancies
were found, particularly in cases with high-frequency oscillations, good agreement was achieved in most cases. Accordingly,
we conclude that the present theory captures well real phenomena in the wake downstream of a cylinder subjected to a flow. 相似文献
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Shoichi?HaraEmail author Kenji?Yamakawa Kunihiro?Hoshino Kazuhiro?Yukawa 《Journal of Marine Science and Technology》2004,8(3):138-146
A huge floating offshore platform (359m long, 60m wide, and 3m deep) was towed into the Pacific Ocean for a validation experiment for a floating airport. Full-scale measurements of towline tension and the bending strain on the upper-deck were made during towing. The measured bending moment agreed well with numerical calculation without taking the draught and towing speed into consideration. 相似文献
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Kunihiro Hamada Yukio Fujimoto Eiji Shintaku 《Journal of Marine Science and Technology》2002,6(4):205-215
Recently, the significance of ship inspections has been increasingly recognized because sea pollution and safety problems
are occurring more and more frequently. However, current ship inspections rely on the experience of the workers. Therefore,
it is difficult to understand, and hence to improve, the state of ship inspections. In this paper, ship inspection is directed
into three stages (plan, do, and check), and the configurations of a total system to support ship inspections are discussed.
A prototype system for the “plan” and “do” stages is developed. This is realized by organizing the information that relates
to inspection, and defining data models for damage and inspection states. Then the proposed system is integrated with a shipbuilding
computer integrated manufacturing (CIM) system so that the ship's structural information can be used effectively. In addition,
functions to calculate the damage-finding probability, and functions to generate information about damage and the inspection
state are introduced. Therefore, in the planning stage, as inspector can execute a virtual ship inspection, and then the damage-finding
probability of each hull part and oversight areas are calculated automatically. Further, by carrying this system into an inspection,
an inspector can generate damage information and inspection information simply and easily. Some examples of the proposed system
are shown at the end of the paper.
Received: November 12, 2001 / Accepted: January 30, 2002 相似文献
4.
Hirofumi Yoshimoto Shigeo Ohmatsu Kunihiro Hoshino Tetsuro Ikebuchi 《Journal of Marine Science and Technology》1997,2(3):163-172
The objective of this paper is to estimate the slamming load acting on a pontoon-type very large floating structure with a
shallow draft. Experiments were carried out using elastic models with different rigidities in regular waves. The results revealed
that the slamming load was strongly influenced by the rigidity of the model. The conditions under which slamming occurs depended
on the extent of the bottom emergence and the velocity of the relative wave height at the bow of the model. These results
were related to a simple procedure for estimating slamming load. 相似文献
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Eiji Shintaku Yukio Fujimoto Kunihiro Hamada Tetsuya Takeuchi 《Journal of Marine Science and Technology》2000,5(1):40-47
This paper describes a stress sensor using a piezoelectric element which was developed to monitor features of the stress
history of a structural member. The sensor is 90 mm long, 60 mm wide, and 25 mm thick. A stress-level meter can turn on and
off different colored light-emitting diodes (LED) according to the changes in a stress level. A stress-level cross counter
can display the number of cycles which exceeds a specified stress level during a monitoring period. The sensor is bonded onto
a structural member using an adhesive agent. In order to see the performance of the prototype sensor, experiments were carried
out using a fatigue-testing machine. The sensor was bonded onto a smooth specimen and multiple repeated stresses were applied
to that specimen. There were three main findings. (1) The sensor can operate under a stress range from −150 MPa to 150 MPa,
and a frequency from 0.05 Hz to 5 Hz. (2) The stress-level meter can turn the lights of the LED on and off accurately under
any stress amplitude and frequency. (3) When the stress frequency is 1 Hz or less, the stress-level cross counter can count
accurately the number of cycles which exceed the predetermined stress levels.
Received: February 25, 2000 / Accepted: April 11, 2000 相似文献
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Manufacturing of ship piping systems is one of the major production activities in shipbuilding. The schedule of pipe production
has an important impact on the master schedule of shipbuilding. In this research, the ITOC concept was introduced to solve
the scheduling problems of a piping factory, and an intelligent scheduling system was developed. The system, in which a product
model, an operation model, a factory model, and a knowledge database of piping production were integrated, automated the planning
process and production scheduling. Details of the above points were discussed. Moreover, an application of the system in a
piping factory, which achieved a higher level of performance as measured by tardiness, lead time, and inventory, was demonstrated. 相似文献
10.
Development of a theory of constraints based scheduling system for ship piping production 总被引:1,自引:0,他引:1
Manufacturing of ship piping system is one of the major production activities in shipbuilding. The schedule of pipe production
has an important impact on master schedule of shipbuilding. In this research, the theory of constraints (TOC) concept is introduced
to solve the scheduling problems of piping factory, and an intelligent scheduling system is developed. The system integrates
a product model, an operation model, a factory model and a knowledge database of piping production and can make the process
planning and production scheduling automatically. In the paper, details of above points are discussed. Moreover, an application
of the system in a piping factory, which achieves a higher level of performance as measured by tardiness, lead time and inventory,
is demonstrated at the end of the paper. 相似文献