A study of the loading of an oblique wave-current field on a slender cylinder in a 3d flow frame is reported in this paper. The three dimensional expressions describing the characteristics of the combined wave-current...
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A study of the loading of an oblique wave-current field on a slender cylinder in a 3d flow frame is reported in this paper. The three dimensional expressions describing the characteristics of the combined wave-current field in terms of mass, momentum and energy flux conservation equations are formulated. The parameters before the interaction of the oblique wave-free uniform current and current-free waves are used to formulate the kinematics of the flow field. These expressions are also employed to formulate and calculate the loads imparted by the wave-current fluid flow on a bottom mounted slender vertical cylinder. A comparison of the obtained results due to the present model to those obtained using three other models being used in the offshore industry is shown for a range of the normalized current parameters. One of these three models is proposed by the American Petroleum Institute (API), which is based on a superposition principle. Morison et al equation is deployed for the load computations in all cases. Comparisons among the obtained results in a normalized manner are shown anddiscussed.
A pressure armour layer is an essential feature of un-bonded flexible pipes. The layer is made of an inter-locked helically wound metal wire of profiled section, whose primary use is to provide the circumferential str...
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A pressure armour layer is an essential feature of un-bonded flexible pipes. The layer is made of an inter-locked helically wound metal wire of profiled section, whose primary use is to provide the circumferential strength of the pipe to resist internal pressure. The general design philosophy of the layer is defined in API 17J in terms of the stress "utilisation" factor that specifies the maximum allowable average hoop stress in the layer, which is conventionally produced by the elastic stress analysis. during pressure armour layer manufacturing (a cold forming process), the armour wire is however subjected to a sequence of cyclic bending and twisting deformations which take it beyond its material elastic limit. This paper presents FE structure models for investigating the detailed local and residual stress variation during the forming process, and the subsequent stress relaxation as a result of the factory acceptance test (FAT). A study case is presented for illustrating the typical stress and strain behaviour after FAT pressurization. The paper also introduces X-ray diffraction technology as a method for residual stress measurement on full scale samples.
The principal aim of this paper is to study the dynamic behaviour of offshore platforms subjected to wave loading. A general review of offshore structure, wave loading and their effects on offshore structures are pres...
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The principal aim of this paper is to study the dynamic behaviour of offshore platforms subjected to wave loading. A general review of offshore structure, wave loading and their effects on offshore structures are presented. A brief review on the basics of Wavelet analysis is also mentioned in this study. The techniques for modeling wave loading in finite element analyses are described anddiscussed in detail. A series of 3d analyses were carried out using the ABAQUS finite element software to study the effects on the dynamic response of the change in support conditions at the seabed. The effects of wave height, wave period and wave velocity on platform behaviour were studied. The results from time history analysis are characterized using Wavelet Analysis in order to obtain the response pattern due to wave loading. These analyses allow the frequency response of the jacket structures to be described in the time domain. These results give a clear view on the response of jacket structure. The important parameters on offshore modeling have also been identified anddiscussed in this paper. The results presented in this study can be used as a guidance for engineer in order to understand the dynamic behaviour of jacket structures subjected to wave loading.
The proceedings contains 23 papers. Topics discussed include streaming of large virtual environments, virtual reality, desktop virtual interfaces, teaching three dimensional modeling and simulation, building database ...
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The proceedings contains 23 papers. Topics discussed include streaming of large virtual environments, virtual reality, desktop virtual interfaces, teaching three dimensional modeling and simulation, building database applications, hypermedia database visualization and interactive scene manipulation.
In this paper, we present the design and implementation of a VRML97 multi-user layer, which is introduced in the EVE distributed virtual reality platform. Main consideration of our multi-user extension is the ease of ...
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ISBN:
(纸本)0769519210
In this paper, we present the design and implementation of a VRML97 multi-user layer, which is introduced in the EVE distributed virtual reality platform. Main consideration of our multi-user extension is the ease of transforming single-user virtual worlds to multi-user virtual worlds, as well as the conformity with any standard VRML97 browser. Furthermore, we present the EVE's communication plaform, which can be used in order to support Collaborative Virtual Environments (CVEs). Main issues regarding the effective network communication as well as the initialization of the 3d scene are discussed in this paper.
The electronic structure and phase transitions in pure and Cr-doped V2O3 are studied in relation to the 3d spin-orbit interaction and the monoclinic lattice distortion. AV ion cluster model consisting of the V ion pai...
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The electronic structure and phase transitions in pure and Cr-doped V2O3 are studied in relation to the 3d spin-orbit interaction and the monoclinic lattice distortion. AV ion cluster model consisting of the V ion pair along the corundum c-axis is studied within the many-body point of view. No orbital ordering is expected to be present in the antiferromagnetic insulating (AFI) phase and instead of this a large orbital magnetic moment similar to0.7mu(B) exists. In the AFI and paramagnetic insulating (PI) phases, Jahn-Teller like lattice instability causes tilting of the V ion pairs from the c-axis. To study the AFI to PI transition, exchange interaction between the V ion pairs is deduced from the second-order perturbation theory and an effective spin-lattice Hamiltonian is proposed. The transition is found to be a simultaneous order-disorder transition of the magnetic moments and the tilting of the V ion pairs. (C) 2003 Elsevier Science B.V. All rights reserved.
In this paper, we present the design and implementation of a VRML97 multi-user layer, which is introduced in the EVE distributed virtual reality platform. Main consideration of our multi-user extension is the ease of ...
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In this paper, we present the design and implementation of a VRML97 multi-user layer, which is introduced in the EVE distributed virtual reality platform. Main consideration of our multi-user extension is the ease of transforming single-user virtual worlds to multi-user virtual worlds, as well as the conformity with any standard VRML97 browser. Furthermore, we present the EVE's communication platform, which can be used in order to support Collaborative Virtual Environments (CVEs). Main issues regarding the effective network communication as well as the initialization of the 3d scene are discussed in this paper.
The proceedings contain 23 papers. The topics discussed include: coding polygon meshes as compressable ASCII;rapid evaluation of Catmull-Clark subdivision surfaces;MPEG-4 BIFS streaming of large virtual environments a...
ISBN:
(纸本)1581134681
The proceedings contain 23 papers. The topics discussed include: coding polygon meshes as compressable ASCII;rapid evaluation of Catmull-Clark subdivision surfaces;MPEG-4 BIFS streaming of large virtual environments and their animation on the web;facial animation framework for the web and mobile platforms;multiresolution streaming mesh with shape preserving and QoS-like controlling;scheduling level of detail with guaranteed quality and cost;InTml: a description language for VR applications;investigation into effective navigation in desktop virtual interfaces;a generic approach for interfacing VRML browsers to various input devices and creating customizable 3d applications;a collaborative analysis tool for visualization and interaction with spatial data;web3d in ocean science learning environments: virtual big beef creek;teaching 3d modeling and simulation: virtual kelp forest case study;a 3d XML-based customized framework for dynamic models;and building database applications of virtual reality with X-VRML.
describes the results of parallel thermal analysis of hybrid and SMT modules. 2d thermal model is presented in brief Theoretical analysis, modelling and simulation of temperature distribution were done for the realize...
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describes the results of parallel thermal analysis of hybrid and SMT modules. 2d thermal model is presented in brief Theoretical analysis, modelling and simulation of temperature distribution were done for the realized hybrid module (containing thick film and chip components). Simulations of temperature distribution in the realized hybrid module were done taking into account the larger thermal power sources. The experimental part (3d model) is based on thermal measurements of the realized hybrid and SMT modules, using a matrix of flip-chip sensors. Thermal measurements were done at different ambient temperatures anddifferent hybrid and SMT module power values. The obtained simulation and experimental results for the hybrid module are graphically presented. Also, experimental results obtained for the SMT and hybrid module at different ambient temperatures and power loads were compared and analyzed.
We studied nonlinear behaviour of the angular position magnetic field sensor that consists of CMOS integrated circuit chip and a thin ferromagnetic disk. developed numerical 3d model was compared with experimental res...
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We studied nonlinear behaviour of the angular position magnetic field sensor that consists of CMOS integrated circuit chip and a thin ferromagnetic disk. developed numerical 3d model was compared with experimental results with a good agreement. Obtained numerical results were used to determine the linear magnetic working range of the sensor. We also calculated the nonlinear error for the disk positioning relative to the Hall elements and found3.3% of error for the 10 /spl mu/m displacement. We proposed a simple amplitude calibration to strongly reduce nonlinearity coming from misalignment to 0.3% of the full scale. Additional nonlinearity from Hall elements has been discussed. The offset and sensitivity mismatch, contribute to the nonlinearity of the sensor less than 1/spl deg/.
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