• A nonlilear controller for ship autopilotsA nonlilear controller for ship autopilots

    A nonlinear autopilot based on aggregated macro variables has been derived. The domain of design parameters has been defined. The control law depends explicitly on the ship parameters so that it is flexible to change. The performance of the controller was illustrated through a simulation study. Global stability of closed - loop system was proven...

    pdf8 trang | Chia sẻ: huongthu9 | Ngày: 12/08/2021 | Lượt xem: 641 | Lượt tải: 0

  • Change in mode shape nodes of multiple cracked bar - Part I: The theoretical studyChange in mode shape nodes of multiple cracked bar - Part I: The theoretical study

    An explicit expression for natural modes of bar with arbitrary number of cracks has been derived and used for analysis of change in mode shape node induced by the multiple cracks. In addition to the well known fact that mode shape nodes move toward the crack, it has been shown herein that dislocation of nodes caused by a single crack in bar is ...

    pdf16 trang | Chia sẻ: huongthu9 | Ngày: 12/08/2021 | Lượt xem: 729 | Lượt tải: 0

  • Change in mode shape nodes of multiple cracked barChange in mode shape nodes of multiple cracked bar

    The obtained numerical results show that the intermediate single node is generally arranged to move toward the crack that is closer to it. It may move toward farther crack if depth of the crack is larger than that of the rest. In the case of multiple nodes, the effect of a crack on dislocation of a node becomes more significant if the crack appr...

    pdf15 trang | Chia sẻ: huongthu9 | Ngày: 12/08/2021 | Lượt xem: 646 | Lượt tải: 0

  • Determination of mode shapes of a multiple cracked beam element and its application for free vibration analysis of a multi-Span continuous beamDetermination of mode shapes of a multiple cracked beam element and its application for free vibration analysis of a multi-Span continuous beam

    The article presents some results on the determination of vibration shape functions of a multiple cracked elastic beam element, where the multiple cracked beam element is modeled as an assembly of intact sub-segments connected by massless rotational springs. Also, algorithms and computer programs are established for analyzing changes in mode shap...

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  • Buckling of double-Walled carbon nanotubesBuckling of double-Walled carbon nanotubes

    In this study it has been demonstrated that the finite difference method can be successfully applied to buckling of double-walled carbon nanotubes since it yields extremely reliable results. The best approximation for the clamped-free DWCNT is 5.590 (Tab. 1), and the best approximation for the simply supported at both ends is 22.236 (Tab. 2). T...

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  • An effective algorithm for reliability-Based optimization of stiffened mindlin plateAn effective algorithm for reliability-Based optimization of stiffened mindlin plate

    The paper presents an approach to establish and solve two reliability-based design optimization problems for Mindlin plate stiffened by Timoshenko beams. In the first problem, static analysis is considered. The objective function is the minimum of the strain energy with constraints on displacement. In the second problem, free vibration analysis i...

    pdf14 trang | Chia sẻ: huongthu9 | Ngày: 12/08/2021 | Lượt xem: 674 | Lượt tải: 0

  • Numerical analysis of free vibration of cross-Ply thick laminated composite cylindrical shells by continuous element methodNumerical analysis of free vibration of cross-Ply thick laminated composite cylindrical shells by continuous element method

    This article has succeeded in constructing the CEM model and in creating a computing program by Matlab to solve the problem of vibration of thick composite cylindrical shells using Continuous Element Method. Through different comparisons with the published results and with the other calculation methods, the obtained results are very satisfied. N...

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  • A co-Rotational beam element for geometrically nonlinear analysis of plane framesA co-Rotational beam element for geometrically nonlinear analysis of plane frames

    In this paper, a co-rotational beam element for geometrically nonlinear analysis of plane frames has been formulated. The shallow arch expression was adopted for the local strain and the exact polynomials obtained from the field consistence approach were employed as interpolation functions for the transversal displacement and sectional rotation....

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  • Postbuckling of functionally graded cylindrical shells based on improved donnell equationsPostbuckling of functionally graded cylindrical shells based on improved donnell equations

    This paper presents an analytical approach to investigate buckling and postbuckling behaviors of FGM circular cylindrical shells subjected to axial compressive load, uniform external pressure accounting for the effects of temperature conditions. Equilibrium equations are established within the framework of improved Donnell shell theory taking int...

    pdf17 trang | Chia sẻ: huongthu9 | Ngày: 12/08/2021 | Lượt xem: 616 | Lượt tải: 0

  • A method of skin frictional resistant reduction by creating small bubbles at bottom of shipsA method of skin frictional resistant reduction by creating small bubbles at bottom of ships

    Small bubble injection method has an effect on reduction ship resistance, and therefore, the ship energy consumption is reduction, correlatively. In calm water, the small bubble injection method has a good effect on a ship at an interval identified operating speed. In this research, experiments were carried out with a 20000 ton model ship, then,...

    pdf11 trang | Chia sẻ: huongthu9 | Ngày: 12/08/2021 | Lượt xem: 731 | Lượt tải: 0