論文 - 森田 千尋
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Buckling and post-bucklin phenomena of cylindrical shell under axail compression and torsion loading 査読あり
Zhao C., Matsida H., Morita C., Huang M.
EASEC-11 - Eleventh East Asia-Pacific Conference on Structural Engineering and Construction 2008年12月
記述言語：英語 掲載種別：研究論文（国際会議プロシーディングス） 出版者・発行元：EASEC-11 - Eleventh East Asia-Pacific Conference on Structural Engineering and Construction
In order to investigate the buckling and post-buckling phenomena of thin-walled cylindrical shells, these experiments were carried out by using Digital Image Correlation Method (DIC). The tested specimens have a thickness of 0.131mm and the ratio of external diameter (R) to thickness (H) R/H is 252. DICM is an optical instrument which utilizes the full-field and non-contact measurement to gauge the three-dimensional displacement and strains on materials and structural components. DICM has been proven to be a flexible and useful tool for deformation analysis. In this paper, DIC system, with two high resolution digital cameras, is applied to observe the buckling generation process in details and make a record of the surface displacements during the tests of cylindrical shell subjected to axial compression and torsion loading, and displacements are obtained and shown in color contour in full field region. The experimental study shows that visualization of buckling behaviors on thin-walled cylindrical shells by using DIC techniques is potential. Typical full-field strain patterns from the buckling tests are obtained both of compression test and torsion test. Test results are compared and discussed in present paper.
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Ma X., Morita C., Sakiyaina T., Matsuda H., Huang M.
Advances in Heterogeneous Material Mechanics 2008 - Proceedings of the 2nd International Conference on Heterogeneous Material Mechanics, ICHMM 2008 1555 - 1558 2008年11月
記述言語：英語 掲載種別：研究論文（国際会議プロシーディングス） 出版者・発行元：Advances in Heterogeneous Material Mechanics 2008 - Proceedings of the 2nd International Conference on Heterogeneous Material Mechanics, ICHMM 2008
The objective of this paper is to clarify the characteristics of vibration of plates with variable thickness and with a hole defect by analytical and experimental methods. The vibration frequencies and modes obtained by proposed discrete method are verified with the experimental results. Moreover, the effects of the thickness of plates, size of the defect on free vibration behavior of plates are shown.
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Free vibration analysis of rectangular plates with variable thickness and point supports 査読あり
Huang M., Ma X., Sakiyama T., Matsuda H., Morita C.
Journal of Sound and Vibration 300 ( 3-5 ) 435 - 452 2007年3月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Sound and Vibration
A discrete method is developed for analyzing the free vibration problem of rectangular plates with point supports. The fundamental differential equations involving Dirac's delta function are established for the bending problem of the plate with point supports. By transforming these differential equations into integral equations and using numerical integration, the solution of these equations is obtained and used as Green function to obtain the characteristic equation of the free vibration. The effects of the point support, the boundary condition, the variable thickness and aspect ratio on the frequencies are considered. By comparing the numerical results obtained by the present method with those previously published, the efficiency and accuracy of the present method are investigated. © 2005 Elsevier Ltd. All rights reserved.
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Performance of weathering steel in bridges in kyushu-yamaguchi region 査読あり
Yamaguchi E., Nakamura S., Hirokado K., Morita C., Sonoda Y., Aso T., Watanabe H., Yamaguchi K., Iwatsubo K.
Doboku Gakkai Ronbunshuu A 62 ( 2 ) 243 - 254 2006年12月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Doboku Gakkai Ronbunshuu A
Many weathering steel bridges have been constructed in recent years. However, the performance of the steel in those bridges is not well traced and so little known. Against this background, "Committee on the Performance of Weathering Steel Bridges in Kyushu-Yamaguchi Region" in Kyushu Association for Bridge and Structural Engineering (KABSE) , conducted the filed study of performance of weathering steel in bridges in the region. This paper describes the result of this study, based on which the factors that may influence the rust development are also discussed.
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Huang M., Ma X., Sakiyama T., Matuda H., Morita C.
Journal of Sound and Vibration 288 ( 4-5 ) 931 - 955 2005年12月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Sound and Vibration
A discrete method is developed for analyzing the free vibration problem of orthotropic rectangular plates with variable thickness. The Green function, which is obtained by transforming the differential equations into integral equations and using numerical integration, is used to establish the characteristic equation of the free vibration. The effects of the aspect ratios, boundary conditions, the variation of the thickness on the frequencies are considered. By comparing the numerical results obtained by the present method with the those previously published, the efficiency and accuracy of the present method are investigated. The frequency parameters are obtained for the orthotropic plates with general boundary conditions and variable thickness in one or two directions. The model shapes are given for some of the square plates with three kinds of thickness variations. © 2005 Elsevier Ltd. All rights reserved.
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Vibration analysis of twisted plates using first order shear deformation theory 査読あり
Hu X., Sakiyama T., Xiong Y., Matsuda H., Morita C.
Journal of Sound and Vibration 277 ( 1-2 ) 205 - 222 2004年10月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Sound and Vibration
Based on general shell theory and the first order shear deformation theory, an accurate relationship between strains and displacements of a twisted plate is derived by the Green strain tensor. An equation of equilibrium for free vibration is given by the principle of virtual work and the governing equation is solved by using the Rayleigh-Ritz method with sets of orthonormal polynomials in which only the first polynomials are defined according to the geometric boundary conditions of a plate and the others are generated by the Gram-Schmidt process. The numerical verification is carried out by comparing with previous results of cantilever plates. Vibration characteristics of cantilever twisted plates such as frequency parameters and corresponding mode shapes are obtained by the present numerical method, and the effects of the twist angle, the aspect ratio and the thickness ratio on them are studied. © 2003 Elsevier Ltd. All rights reserved.
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Fundamental vibration of rotating cantilever blades with pre-twist 査読あり
Hu X., Sakiyama T., Matsuda H., Morita C.
Journal of Sound and Vibration 271 ( 1-2 ) 47 - 66 2004年3月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Sound and Vibration
A non-linear strain-displacement relationship of a pre-twisted conical shell on the general shell theory is utilized, and a method for vibration of a rotating cantilever conical shell with pre-twist is developed by the principle of virtual work and the Rayleigh-Ritz method. Firstly, deformation and stress resultants caused by rotation are analyzed. Secondly, an equilibrium of energy for vibration of a pre-twisted conical shell having the conditions achieved in the first process is given and then an eigenfrequency equation of a rotating cantilever conical shell with pre-twisted is formulated. The effects of parameters such as an angular velocity, a radius of a hub, a setting angle, a twist angle, a subtended angle and a tapered ratio of cross-section on the fundamental vibration are investigated. © 2003 Elsevier Ltd. All rights reserved.
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Vibration of angle-ply laminated plates with twist by Rayleigh-Ritz procedure 査読あり
Hu X., Sakiyama T., Lim C., Xiong Y., Matsuda H., Morita C.
Computer Methods in Applied Mechanics and Engineering 193 ( 9-11 ) 805 - 823 2004年3月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Computer Methods in Applied Mechanics and Engineering
Considering transverse strain and rotary inertia, an analytical method for vibration of an angle-ply laminated plate with twist is proposed. An accurate strain-displacement relationship of a twisted plate is derived by the Green strain tensor on the general shell theory and the Mindlin plate theory. The equilibrium for free vibration is given out by the principle of virtual work and is solved by using the Rayleigh-Ritz procedure with normalized characteristic orthogonal polynomials generated by the Gram-Schmidt process. The convergence and the accuracy of the present method are investigated. The parametric effects of a fibre angle, a twist angle, a thickness ratio and a stacking sequence on vibration frequencies and mode shapes of laminated plates are studied. © 2003 Elsevier B.V. All rights reserved.
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Ario I., Morita C., Suyama H., Sato E., Fujii K.
Nippon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A 69 ( 1 ) 148 - 153 2003年1月
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Nippon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A
We suppose that most organisms have the optimized structures under various environment, but its mechanism has the most complex and many unknown factors. In this paper, we propose that it is useful in engineering to obtain the mechanism of a bamboo structure using the laminate sheet model, through the experiments and the observation of the organizational structure within fibers of a bamboo. Based on the fundamental research of the fiber contents and strength of the bamboo's slices, we could learn how to construct the more fiber or the laminated composite structures by numerical analysis of the elastic-plastic FEM. This paper denoted that it is applicable to obtain the organizational properties of bamboo by the laminate sheet model.
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Free vibration of orthotropic square plates with a square hole 査読あり
Sakiyama T., Huang M., Matsuda H., Morita C.
Journal of Sound and Vibration 259 ( 1 ) 63 - 80 2003年
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Sound and Vibration
An approximate method is extended for analyzing the free vibration problem of orthotropic square plate with a square hole. In this paper, a square plate with a square hole is transformed into an equivalent square plate with non-uniform thickness by considering the hole as an extremely thin part of the equivalent plate. Therefore, the dynamic characteristics of a plate with a hole can be obtained by analyzing the equivalent plate. The Green function, which is the discrete solution for the deflection of the equivalent plate, is used to obtain the characteristic equation of the free vibration. The effects of the side to thickness ratio, hole side to plate side ratio and the variation of the thickness on the frequencies are considered. Some numerical analyses are carried out for the simply supported orthotropic square plate with a square hole. The efficiency and accuracy of the numerical solutions by the present method are investigated. © 2002 Elsevier Science Ltd. All rights reserved.
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Free vibration analysis of orthotropic right cantilever triangular plates 査読あり
Sakiyama T., Huang M., Matsuda H., Morita C.
Journal of Sound and Vibration 259 ( 1 ) 219 - 228 2003年
記述言語：英語 掲載種別：研究論文（学術雑誌）
An approximate method was proposed for the free vibration of orthotropic right cantilever triangular plate with various aspect ratios and variable thickness. An equivalent rectangular was used to replace the right triangular plate in the free vibration analysis. Based on the Green function of the equivalent rectangular plate, the characteristic equation of free vibration was obtained. The results showed that the numerical solutions obtained by the proposed method had good convergence and satisfactory accuracy.
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Vibration analysis of rotating twisted and open conical shells 査読あり
Hu X., Sakiyama T., Matsuda H., Morita C.
International Journal of Solids and Structures 39 ( 25 ) 6121 - 6134 2002年12月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：International Journal of Solids and Structures
Based on a non-linear strain-displacement relationship of a non-rotating twisted and open conical shell on thin shell theory, a numerical method for free vibration of a rotating twisted and open conical shell is presented by the energy method, where the effect of rotation is considered as initial deformation and initial stress resultants which are obtained by the principle of virtual work for steady deformation due to rotation, then an energy equilibrium of equation for vibration of a twisted and open conical shell with the initial conditions is also given by the principle of virtual work. In the two numerical processes, the Rayleigh-Ritz procedure is used and the two in-plane and a transverse displacement functions are assumed to be algebraic polynomials in two elements. The effects of characteristic parameters with respect to rotation and geometry such as an angular velocity and a radius of rotating disc, a setting angle, a twist angle, curvature and a tapered ratio of cross-section on vibration performance of rotating twisted and open conical shells are studied by the present method. © 2002 Elsevier Science Ltd. All rights reserved.
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Vibration of cantilevered laminated composite conical shells with twist 査読あり
Sakiyama T., Hu X., Matsuda H., Morita C.
High Performance Structures and Materials 4 47 - 55 2002年12月
記述言語：英語 掲載種別：研究論文（国際会議プロシーディングス） 出版者・発行元：High Performance Structures and Materials
Considering an accurate relationship between strains and displacements derived on the thin shell theory for twisted thin conical shells, a method for analyzing the vibrations of twisted conical shells made up of laminated composite materials is presented, in which the principle of virtual work for free vibrations and the Rayleigh-Ritz procedure with algebraic polynomials in two elements as displacements are adopted. The effects of the number of laminae, the fiber orientation, the twist, the taper ratio and the subtended angle on the vibration characteristics of cantilevered laminated composite conical shells are studied by the present method.
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Vibration analysis of twisted conical shells with tapered thickness 査読あり
Hu X., Sakiyama T., Matsuda H., Morita C.
International Journal of Engineering Science 40 ( 14 ) 1579 - 1598 2002年8月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：International Journal of Engineering Science
Considering twisted conical shells with tapered thickness, a numerical method for analyzing free vibration is developed, where an exact strain-displacement relationship of twisted conical shells is derived based on the shell theory, the equation of energy equilibrium for free vibration is formulated by the principle of virtual work, and the governing equation is obtained by the Rayleigh-Ritz procedure. The convergent property is investigated in view of the assumed displacement functions, and the comparison between the present and the available previous results for several typical conical shells is carried out in order to demonstrate the practicability and the accuracy. The effects of the tapered thickness in two directions, the twist angle, the subtended angle and the taper ratio of cross-section on the vibration behavior are discussed through the frequencies and corresponding mode shapes. © 2002 Published by Elsevier Science Ltd.
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Vibration of twisted laminated composite conical shells 査読あり
Hu X., Sakiyama T., Matsuda H., Morita C.
International Journal of Mechanical Sciences 44 ( 8 ) 1521 - 1541 2002年8月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：International Journal of Mechanical Sciences
A methodology for free vibration of a laminated composite conical shell with twist is proposed, in which a strain-displacement relationship of a twisted conical shell is given by considering the Green strain tensor on the general thin shell theory, the principle of virtual work is utilized, and the governing equation is formulated by the Rayleigh-Ritz procedure with algebraic polynomials in two elements as admissible displacement functions. The convergence, the accuracy and the validity of the methodology are verified by comparisons. As a result of the vibration frequencies and mode shapes, the effects of the laminated constructional and the geometric parameters, such as the number of laminae, the fiber orientation angles, the twist angle, the subtended angle and the taper ratio, on the vibration characteristics are studied by the present methodology. © 2002 Elsevier Science Ltd. All rights reserved.
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Vibration of twisted and curved cylindrical panels with variable thickness 査読あり
Sakiyama T., Hu X., Matsuda H., Morita C.
Journal of Sound and Vibration 254 ( 3 ) 481 - 502 2002年7月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Sound and Vibration
A numerical procedure, with an exact strain-displacement relationship of twisted and curved cylindrical panels having variable thickness derived by considering the Green strain tensor on general shell theory, is presented using the principle of virtual work and the Rayleigh-Ritz method with algebraic polynomials as in-plane and transverse displacement functions. The accuracy and applicability of the procedure are verified by comparing the present results with previous experimental and theoretical results for several panels. The effects of variation ratio of thickness in chordwise and lengthwise directions, twist, and curvature both in two directions aforementioned on vibrations of cylindrical panels are studied in detail, and typical vibration mode shapes are plotted to demonstrate the effects.
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Sakiyama T., Matsuda H., Morita C.
Journal of Sound and Vibration 203 ( 3 ) 505 - 522 1997年6月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Sound and Vibration
In this paper, a method of analysis for the free vibration of a three-layer sandwich arch with an elastic or viscoelastic core, and with various kinds of axis-shape and boundary conditions is presented. The characteristic equation of the free vibration is derived by applying Green functions. The Green functions are obtained in a discrete form for various kinds of sandwich arches with non-uniform cross-section and radius of curvature. They enable the setting up of the frequency equation in eigenvalue form. © 1997 Academic Press Limited.
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Sakiyama T., Matsuda H., Morita C.
Journal of Sound and Vibration 198 ( 4 ) 439 - 454 1996年12月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Sound and Vibration
In this paper, an analytical method for the free vibration of a three-layer, continuous sandwich beam with an elastic or viscoelastic core and arbitrary boundary conditions is presented. The characteristic equation for finding the natural frequencies and modes is derived by introducing a discrete-type Green function which is a discrete solution of the differential equation governing the flexural behaviour of a sandwich beam under the action of a concentrated load. The Green function can be obtained equally for a beam with a non-uniform cross-section as well as a beam with uniform cross-section, and it enables the setting up of the frequency equation in eigenvalue form, so that the free vibration of the beam can be analysed efficiently without any calculation using a trial and error method. The numerical solution is shown to have a uniform convergency and good accuracy, and some effects of varying the elastic or viscoelastic core shear modulus and depths of core on the natural frequency and loss factor of a continuous sandwich beam are evaluated. © 1996 Academic Press Limited.
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Sakiyama T., Matsuda H., Morita C.
Journal of Sound and Vibration 191 ( 2 ) 189 - 206 1996年3月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Sound and Vibration
A method of analysis of the free vibration of a three-layer sandwich beam with an elastic or viscoelastic core and arbitrary boundary conditions is presented. The characteristic equation of the free vibration is derived by applying the Green function which is obtained as a discrete solution of differential equations governing the flexural behaviour of the sandwich beam under the action of a concentrated load. By applying the characteristic equation, the behaviour of the free vibration of the sandwich beam with an elastic or viscoelastic core can be analyzed efficiently without a calculation by a trial and error method. It is shown that the numerical solution has uniform convergence and good accuracy, and the effect of the elastic or viscoelastic core shear modulus and the depth of the core on the natural frequency and the loss factor of the sandwich beam are evaluated. © 1996 Academic Press Limited.
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A FREE VIBRATION ANALYSIS OF ANISOTROPIC RECTANGULAR PLATES WITH VARIOUS BOUNDARY CONDITIONS 査読あり
Morita C., Matsuda H., Sakiyama T., Hagino T.
Journal of Sound and Vibration 187 ( 5 ) 757 - 770 1995年11月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Sound and Vibration
An approximate method in which discrete Green functions are used is described for analyzing the free vibration of anisotropic rectangular plates with various boundary conditions. The discrete Green functions are obtained by transforming the differential equations involving Dirac's delta functions into integral equations and numerically integrating them. By employing these discrete Green functions, the differential equations governing the free vibration of anisotropic rectangular plates are transformed into the equivalent boundary integral equations, which are then solved to obtain the eigenvalues and eigenmodes. Comparisons with existing results confirm the accuracy of the numerical solutions obtained by the method. Results are presented for anisotropic rectangular plates with a number of combinations of clamped and simply supported edges and various angles of fiber orientation. © 1995 Academic Press. All rights reserved.