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1.
Shogo Nakasumi Katsuyuki Suzuki Daiji Fujii Hideomi Ohtsubo 《Journal of Marine Science and Technology》2003,7(4):180-188
This article presents a mixed method of analyzing shell elements and solid elements using the overlaying mesh method. In
the structural design of a ship's hull, the shell elements are used for the global model. However, the solid elements are
necessary to analyze the stress concentration zones or the vicinity of a crack. In such cases, the models are analyzed using
zooming analysis, in which the results of a global model analysis are transferred to a local model analysis by imposing boundary
conditions. This method is more advantageous than zooming analysis in terms of the accuracy of the solution and the modeling
flexibility. Some examples of a plate model with a cracked surface or with a projection are shown in order to demonstrate
the effectiveness of the method.
Received: August 6, 2002 / Accepted: November 25, 2002
Address correspondence to: S. Nakasumi (sumi@nasl.t.u-tokyo.ac.jp)
Updated from the Japanese original, which won the 2002 SNAJ prize (J Soc Nav Archit Jpn 2001;189:219–224; and 190:655–662) 相似文献
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3.
A constrained interpolation profile (CIP)-based Cartesian grid method for strongly nonlinear wave–body interaction problems
is presented and validated by a newly designed experiment, which is performed in a two-dimensional wave channel. In the experiment,
a floating body that has a rectangular section shape is used. A superstructure is installed on the deck and a small floating-body
freeboard is adopted in order to easily obtain water-on-deck phenomena. A forced oscillation test in heave and a wave–body
interaction test are carried out. The numerical simulation is performed by the CIP-based Cartesian grid method, which is described
in this paper. The CIP scheme is applied in the Cartesian grid-based flow solver. New improvements of the method include an
interface-capturing method that applies the tangent of hyperbola for interface capturing (THINC) scheme and a virtual particle
method for the floating body. The efficiency of the THINC scheme is shown by a dam-breaking computation. Numerical simulations
on the experimental problem for both the forced oscillation test and the wave–body interaction test are carried out, and the
results are compared to the measurements. All of the comparisons are reasonably good. It is shown, based on the numerical
examples, that the present CIP-based Cartesian grid method is an accurate and efficient method for predicting strongly nonlinear
wave–body interactions. 相似文献
4.
对中碳钢大厚度结构的焊接工艺流程的每个步骤都做了详尽的技术说明,通过对结构以及母材的可焊性分析,制定合理的焊接工艺措施,取得了满意的效果,可为类似的焊接作业提供借鉴。 相似文献
5.
YOU Guang-xin PANG Yong-jie JIANG Da-peng 《船舶与海洋工程学报》2005,4(2):7-12
A“Market” based framework for multiple AUVs team is introduced in this paper. It is a distributed meta-level task allocation framwork. The formulation and the basic concepts of the “Market” such as “goods” and “price” are discussed first, then the basic algorithm of the “auction”. The loosely coupled v-MDTSP tasks are considered as an example of the task allocation mission. A multiple AUV team controller and a detailed algorithm are developed for such applications. The simulation results show that the controller has the advantages such as robustness and low complexity and it can achieve better optimization results than the classical central controller ( such as GA) in some tasks. And the comparison of two different local solvers also implies that we should get the reasonable task allocation even not using the high quality algorithm, which can considerably decrease the cooperation computation. 相似文献
6.
通过对比国产和进口30#直馏沥青的性能,并对浇注式沥青混凝土配合比设计以及施工控制进行阐述,进而验证了国产30#直馏沥青在浇注式沥青混凝土中应用的可行性,为浇注式沥青混凝土胶结料国产化应用和施工控制提供参考。 相似文献
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An analysis of the determinants of children’s weekend physical activity participation 总被引:1,自引:0,他引:1
This paper examines the out-of-home, weekend, time-use patterns of children aged 5–17 years, with a specific emphasis on their
physical activity participation. The impact of several types of factors, including individual and household demographics,
neighborhood demographics, built environment characteristics, and activity day variables, on physical activity participation
is analyzed using a joint nested multiple discrete–continuous extreme value-binary choice model. The sample for analysis is
drawn from the 2000 San Francisco Bay Area Travel Survey. The model developed in the paper can be used to assess the impacts
of changing demographics and built environment characteristics on children’s physical activity levels. 相似文献
9.
Jungyong Wang Ayhan Akinturk Neil Bose Stephen J. Jones Yun Young Song Ho Hwan Chun Moon Chan Kim 《Journal of Marine Science and Technology》2008,13(3):244-255
The objective of this study was to investigate the performance of a model azimuthing podded propulsor in ice-covered water.
Model tests were carried out with two different depths of cut into the ice (15 and 35 mm), two different ice conditions (presawn
and pack ice conditions), and four different azimuthing angles. The depth of cut is the maximum penetration depth of the propeller
blade into the ice block. The 0.3-m-diameter model propeller was operated in a continuous ice milling condition. Ice loads
were measured by several sensors which were installed in various positions on the model. Six one-axis pancake-style load cells
on the top of the model measured the global loads and two six-component dynamometers were installed on the shaft to measure
the shaft loads. One six-component dynamometer was attached to the one of the propeller blades inside the hub to measure the
blade loads. The pod unit and propeller performance in ice are presented. Ice-related loads, which were obtained when the
blade was inside the ice block, are introduced and discussed. During the propeller–ice interaction, a blade can experience
the path generated by the previous blade, which is called the shadowing effect. The effects of shadowing, depth of cut, azimuthing
angle, and advance coefficient on propulsor performance are presented and discussed. 相似文献
10.
该文介绍葫芦河特大桥主墩0#块冬季施工方法,对西北严寒地区混凝土生产、运输、施工、养护等成功的经验进行了总结。提出采用"暖棚保温、管道覆盖、暖棚养护"法进行混凝土施工是一种较好的方法。 相似文献