Guoyong Jin · Tiangui Ye Zhu Su Structural Vibration A Uniform Accurate Solution for Laminated Beams, Plates and Shells with General Boundary Conditions Structural Vibration Guoyong Jin Tiangui Ye (cid:129) (cid:129) Zhu Su Structural Vibration A Uniform Accurate Solution for Laminated Beams, Plates and Shells with General Boundary Conditions 123 Guoyong Jin ZhuSu College ofPower andEnergy Engineering College ofPower andEnergy Engineering Harbin EngineeringUniversity Harbin EngineeringUniversity Harbin Harbin China China Tiangui Ye College ofPower andEnergy Engineering Harbin EngineeringUniversity Harbin China ISBN 978-3-662-46363-5 ISBN 978-3-662-46364-2 (eBook) DOI 10.1007/978-3-662-46364-2 Jointlypublished withScience Press, Beijing ISBN:978-7-03-043594-1 Science Press,Beijing LibraryofCongressControlNumber:2015930816 SpringerHeidelbergNewYorkDordrechtLondon ©SciencePress,BeijingandSpringer-VerlagBerlinHeidelberg2015 Thisworkissubjecttocopyright.AllrightsarereservedbythePublishers,whetherthewholeorpart of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilarmethodologynowknownorhereafterdeveloped. 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Printedonacid-freepaper Springer-VerlagGmbHBerlinHeidelbergispartofSpringerScience+BusinessMedia (www.springer.com) Preface Inpracticalapplicationsthatrangefromouterspacetothedeepoceans,engineering structuressuchasaircraft,rockets,automobiles,turbines,architectures,vessels,and submarines often work in complex environments and can be subjected to various dynamic loads, which can lead to the vibratory behaviors of the structures. In all these applications, the engineering structures may fail and collapse because of material fatigue resulting from vibrations. Many calamitous incidents have shown the destructive nature of vibrations. For instance, the main span of the famous Tacoma Narrows Bridge suffered severe forced resonance and collapsed in 1940 due to the fact that the wind provided an external periodic frequency that matched oneofthenaturalstructuralfrequenciesofthebridge.Furthermore,noisegenerated byvibrationsalwayscausesannoyance,discomfort,andlossofefficiencytohuman beings. Therefore, it is of particular importance to understand the structural vibrations and reduce them through proper design to ensure a reliable, safe, and lasting structural performance. An important step in the vibration design of an engineeringstructureistheevaluationofitsvibrationmodalcharacteristics,suchas natural frequencies and mode shapes. This modal information plays a key role in the design and vibration suppression of the structure when subjected to dynamics excitations. In engineering applications, a variety of possible boundary restraining casesmaybeencounteredforastructure.Inrecentdecades,theabilityofpredicting the vibration characteristics of structures with general boundary conditions is of primeinteresttoengineersanddesignersandisthemutualconcernofresearchersin this field as well. Beams, plates, and shells are basic structural elements of most engineering structuresandmachines.Athoroughunderstandingoftheirvibrationcharacteristics isofgreatsignificanceforengineerstopredictthevibrationsofthewholestructures anddesignsuitablestructureswithlowvibrationandnoiseradiationcharacteristics. There exists many books, papers, and research reports on the vibration analysis of beams, plates, and shells. In 1969, Prof. A.W. Leissa published the excellent monograph Vibration of Plates, in which theoretical and experimental results of approximately 500 research papers and reports were presented. And in 1973, he organized and summarized approximately 1,000 references in the field of shell v vi Preface vibrations and published another famous monograph entitled Vibration of Shells. New survey shows that the literature on the vibrations of beams, plates, and shells has expanded rapidly since then. Based on the Google Scholar search tool, the numbers of article related to the following keywords from 1973 up to 2014 are: 315,000itemsfor“vibration&beam,”416,000itemsfor“vibration&plates,”and 101,000 items for “vibration & shell.” This clearly reveals the importance of the vibration analysis of beams, plates, and shells. Undeniably, significant advances in the vibration analysis of beams, plates, and shells have been achieved over the past four decades. Many accurate and efficient computational methods have also been developed, such as the Ritz method, dif- ferentialquadraturemethod(DQM),Galerkinmethod,wavepropagationapproach, multiquadric radial basis function method (MRBFM), meshless method, finite element method (FEM), discrete singular convolution approach (DSC), etc. Furthermore, a large variety of classical and modern theories have been proposed by researchers, such as the classical structure theories (CSTs), the first-order shear deformation theories (FSDTs), and the higher order shear deformation theories (HSDTs). However, after the review of the literature in this subject, it appears that most of the books deal with a technique that is only suitable for a particular type of classicalboundaryconditions(i.e.,simplysupportedsupports,clampedboundaries, free edges, shear-diaphragm restrains and their combinations), which typically requires constant modifications of the solution procedures and corresponding computation codes to adapt to different boundary cases. This will result in very tedious calculations and be easily inundated with various boundary conditions in practical applications since the boundary conditions of a beam, plate, or shell may not always be classical in nature, a variety of possible boundary restraining cases, including classical boundary conditions, elastic restraints, and their combinations may be encountered. In addition, with the development of new industries and modern processes, laminated beams, plates, and shells composed of composite laminasareextensivelyusedinmanyfieldsofmodernengineeringpracticessuchas space vehicles, civil constructions, and deep-sea engineering equipments to satisfy special functional requirements due to their outstanding bending rigidity, high strength-weight and stiffness-weight ratios, excellent vibration characteristics, and goodfatigueproperties.Thevibrationresultsoflaminatedbeams,plates,andshells arefarfromcomplete.Itisnecessaryandofgreatsignificancetodevelopaunified, efficient, and accurate method which is capable of universally dealing with lami- nated beams, plates, and shells with general boundary conditions. Furthermore, a systematic, comprehensive, and up-to-date monograph which contains vibration resultsofisotropicandlaminatedbeams,plates,andshellswithvariouslamination schemesandgeneralboundaryconditionswouldbehighlydesirableandusefulfor the senior undergraduate and postgraduate students, teachers, engineers, and indi- vidual researchers in this field. Inviewoftheseapparentvoids,thepresentmonographpresentsanendeavorto complementthevibrationanalysisoflaminatedbeams,plates,andshells.Thetitle, Preface vii Structural Vibration: A Uniform Accurate Solution for Laminated Beams, Plates andShellswithGeneralBoundaryConditions,illustratesthemainaimofthisbook, namely: (1) Todevelopanaccuratesemi-analyticalmethodwhichiscapableofdealingwith thevibrationsoflaminatedbeams,plates,andshellswitharbitrarylamination schemesandgeneralboundaryconditionsincludingclassicalboundaries,elastic supports and their combinations, aiming to provide a unified and reasonable accuratealternativetootheranalyticalandnumericaltechniques. (2) Toprovideasummaryofknownresultsoflaminatedbeams,plates,andshells withvariouslaminationschemesandgeneralboundaryconditions,whichmay serve as benchmark solutions for the future research in this field. The book is organized into eight chapters. Fundamental equations of laminated shellsintheframeworkofclassicalshelltheoryandsheardeformationshelltheory are derived in detail, including the kinematic relations, stress–strain relations and stress resultants, energy functions, governing equations, and boundary conditions. The corresponding fundamental equations of laminated beams and plates are spe- cialized from the shell ones. Following the fundamental equations, a unified modified Fourier series method is developed. Then both strong and weak form solution procedures are realized and established by combining the fundamental equations and the modified Fourier series method. Finally, numerous vibration results are presented for isotropic, orthotropic, and laminated beams, plates, and shellswithvariousgeometryandmaterialparameters,differentlaminationschemes and different boundary conditions including the classical boundaries, elastic ones, and their combinations. Summarizing, the work is arranged as follows: The theories of linear vibration of laminated beams, plates, and shells are well established. In this regard, Chap. 1 introduces the fundamental equations of lami- nated beams, plates, and shells in the framework of classical shell theory and the first-order shear deformation shell theory without proofs. Chapter2presentsamodifiedFourierseriesmethodwhichiscapableofdealing with vibrations of laminated beams, plates, and shells with general boundary conditions.InthemodifiedFourierseriesmethod,eachdisplacementofalaminated beam,plate,orshell,regardlessofboundaryconditions,isinvariantlyexpressedas a new form of trigonometric series expansions in which several supplementary terms are introduced to ensure and accelerate the convergence of the series expansion.Thenonecanseekthesolutionseitherinstrongformsolutionprocedure or the weak form one. These two solution procedures are fully illustrated in this chapter. Chapters 3–8 deal with laminated beams, plates, and cylindrical, conical, spherical and shallow shells, respectively. In each chapter, corresponding funda- mental equations in the framework of classical and shear deformation theories for the general dynamic analysis are developed first, which can be useful for potential readers. Following the fundamental equations, numerous free vibration results are presented for various configurations including different boundary conditions, lam- inated sequences, and geometry and material properties. viii Preface Finally, the authors would like to record their appreciation to the National Natural Science Foundation of China (Grant Nos. 51175098, 51279035, and 10802024) and the Fundamental Research Funds for the Central Universities of China (No. HEUCFQ1401) for partially funding this work. Contents 1 Fundamental Equations of Laminated Beams, Plates and Shells. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 Three-Dimensional Elasticity Theory in Curvilinear Coordinates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Fundamental Equations of Thin Laminated Shells. . . . . . . . . . 3 1.2.1 Kinematic Relations . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2.2 Stress-Strain Relations and Stress Resultants . . . . . . . 5 1.2.3 Energy Functions . . . . . . . . . . . . . . . . . . . . . . . . . . 9 1.2.4 Governing Equations and Boundary Conditions . . . . . 11 1.3 Fundamental Equations of Thick Laminated Shells . . . . . . . . . 16 1.3.1 Kinematic Relations . . . . . . . . . . . . . . . . . . . . . . . . 17 1.3.2 Stress-Strain Relations and Stress Resultants . . . . . . . 18 1.3.3 Energy Functions . . . . . . . . . . . . . . . . . . . . . . . . . . 23 1.3.4 Governing Equations and Boundary Conditions . . . . . 26 1.4 Lamé Parameters for Plates and Shells. . . . . . . . . . . . . . . . . . 29 2 Modified Fourier Series and Rayleigh-Ritz Method . . . . . . . . . . . 37 2.1 Modified Fourier Series. . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 2.1.1 Traditional Fourier Series Solutions. . . . . . . . . . . . . . 39 2.1.2 One-Dimensional Modified Fourier Series Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 2.1.3 Two-Dimensional Modified Fourier Series Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 2.2 Strong Form Solution Procedure. . . . . . . . . . . . . . . . . . . . . . 53 2.3 Rayleigh-Ritz Method (Weak Form Solution Procedure) . . . . . 58 3 Straight and Curved Beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 3.1 Fundamental Equations of Thin Laminated Beams . . . . . . . . . 64 3.1.1 Kinematic Relations . . . . . . . . . . . . . . . . . . . . . . . . 64 3.1.2 Stress-Strain Relations and Stress Resultants . . . . . . . 65 3.1.3 Energy Functions . . . . . . . . . . . . . . . . . . . . . . . . . . 66 ix x Contents 3.1.4 Governing Equations and Boundary Conditions . . . . . 68 3.2 Fundamental Equations of Thick Laminated Beams. . . . . . . . . 71 3.2.1 Kinematic Relations . . . . . . . . . . . . . . . . . . . . . . . . 71 3.2.2 Stress-Strain Relations and Stress Resultants . . . . . . . 72 3.2.3 Energy Functions . . . . . . . . . . . . . . . . . . . . . . . . . . 73 3.2.4 Governing Equations and Boundary Conditions . . . . . 74 3.3 Solution Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 3.3.1 Strong Form Solution Procedure. . . . . . . . . . . . . . . . 77 3.3.2 Weak Form Solution Procedure (Rayleigh-Ritz Procedure) . . . . . . . . . . . . . . . . . . . . 80 3.4 Laminated Beams with General Boundary Conditions . . . . . . . 83 3.4.1 Convergence Studies and Result Verification . . . . . . . 83 3.4.2 Effects of Shear Deformation and Rotary Inertia. . . . . 85 3.4.3 Effects of the Deepness Term (1 + z/R). . . . . . . . . . . 87 3.4.4 Isotropic and Laminated Beams with General Boundary Conditions. . . . . . . . . . . . . . . . . . . . . . . . 90 4 Plates. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 4.1 Fundamental Equations of Thin Laminated Rectangular Plates. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 4.1.1 Kinematic Relations . . . . . . . . . . . . . . . . . . . . . . . . 100 4.1.2 Stress-Strain Relations and Stress Resultants . . . . . . . 102 4.1.3 Energy Functions . . . . . . . . . . . . . . . . . . . . . . . . . . 103 4.1.4 Governing Equations and Boundary Conditions . . . . . 105 4.2 Fundamental Equations of Thick Laminated Rectangular Plates. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 4.2.1 Kinematic Relations . . . . . . . . . . . . . . . . . . . . . . . . 108 4.2.2 Stress-Strain Relations and Stress Resultants . . . . . . . 108 4.2.3 Energy Functions . . . . . . . . . . . . . . . . . . . . . . . . . . 109 4.2.4 Governing Equations and Boundary Conditions . . . . . 111 4.3 Vibration of Laminated Rectangular Plates. . . . . . . . . . . . . . . 113 4.3.1 Convergence Studies and Result Verification . . . . . . . 116 4.3.2 Laminated Rectangular Plates with Arbitrary Classical Boundary Conditions. . . . . . . . . . . . . . . . . 117 4.3.3 Laminated Rectangular Plates with Elastic Boundary Conditions. . . . . . . . . . . . . . . . . . . . . . . . 122 4.3.4 Laminated Rectangular Plates with Internal Line Supports. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 4.4 Fundamental Equations of Laminated Sectorial, Annular and Circular Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131 4.4.1 Fundamental Equations of Thin Laminated Sectorial, Annular and Circular Plates . . . . . . . . . . . . 134 4.4.2 Fundamental Equations of Thick Laminated Sectorial, Annular and Circular Plates . . . . . . . . . . . . 137
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