Engineering Vibroacoustic Analysis

Taking a practical approach, this book describes methods for simulating the structural vibration, interior acoustics, and sound radiation of mechanical and transportation vehicle systems for low, mid, and high frequencies.

Engineering Vibroacoustic Analysis

Author: Stephen A. Hambric

Publisher: John Wiley & Sons

ISBN: 1119953448

Page: 528

View: 474

The book describes analytical methods (based primarily on classical modal synthesis), the Finite Element Method (FEM), Boundary Element Method (BEM), Statistical Energy Analysis (SEA), Energy Finite Element Analysis (EFEA), Hybrid Methods (FEM-SEA and Transfer Path Analysis), and Wave-Based Methods. The book also includes procedures for designing noise and vibration control treatments, optimizing structures for reduced vibration and noise, and estimating the uncertainties in analysis results. Written by several well-known authors, each chapter includes theoretical formulations, along with practical applications to actual structural-acoustic systems. Readers will learn how to use vibroacoustic analysis methods in product design and development; how to perform transient, frequency (deterministic and random), and statistical vibroacoustic analyses; and how to choose appropriate structural and acoustic computational methods for their applications. The book can be used as a general reference for practicing engineers, or as a text for a technical short course or graduate course.

Engineering Vibroacoustic Analysis

Engineering Analysis with Boundary Elements, 20(4): 305–310, 1997. ... [95] [96] [97] [98] [99] [100] [101] [102] [103] 302 Engineering Vibroacoustic Analysis.

Engineering Vibroacoustic Analysis

Author: Stephen A. Hambric

Publisher: John Wiley & Sons

ISBN: 111869399X

Page: 536

View: 780

The book describes analytical methods (based primarily on classical modal synthesis), the Finite Element Method (FEM), Boundary Element Method (BEM), Statistical Energy Analysis (SEA), Energy Finite Element Analysis (EFEA), Hybrid Methods (FEM-SEA and Transfer Path Analysis), and Wave-Based Methods. The book also includes procedures for designing noise and vibration control treatments, optimizing structures for reduced vibration and noise, and estimating the uncertainties in analysis results. Written by several well-known authors, each chapter includes theoretical formulations, along with practical applications to actual structural-acoustic systems. Readers will learn how to use vibroacoustic analysis methods in product design and development; how to perform transient, frequency (deterministic and random), and statistical vibroacoustic analyses; and how to choose appropriate structural and acoustic computational methods for their applications. The book can be used as a general reference for practicing engineers, or as a text for a technical short course or graduate course.

Vibroacoustic Analysis of Panels Using a Wave and Finite Element Method

The spectral dynamic stiffnesses of the fluids and structure are developed and assembled into the total spectral dynamic stiffness matrix of the coupled system. This is then used to calculate the structural response to excitation.

Vibroacoustic Analysis of Panels Using a Wave and Finite Element Method

Author: Yi Yang

Publisher:

ISBN:

Page: 167

View: 713

This thesis concerns extending a wave and finite element (WFE) method to predict the vibroacoustic characteristics of structures, including wave propagation characteristics, sound transmission loss and sound radiation, of flat infinite and finite panels and infinite cylinders. In this method, a coupled fluid/structure system is considered. A segment of the structure is modelled using a conventional finite element (FE) method. The fluid spaces are modelled analytically. The fluid pressures on the surfaces of the segment exert external nodal forces on the FE model of the structure. Periodicity theory and equilibrium conditions are then used to postprocess the mass and stiffness matrices of the periodic cell together with the nodal forces. The spectral dynamic stiffnesses of the fluids and structure are developed and assembled into the total spectral dynamic stiffness matrix of the coupled system. This is then used to calculate the structural response to excitation. The excitations can be acoustic pressures or general structural excitation. Once the structural displacements are found, the acoustic pressures can be calculated analytically. The WFE method is also used to develop homogenised models of honeycomb cored panels, with the model size being reduced by Guyan reduction. This method is applied to infinite panels, finite panels and cylindrical shells. For simple structures analytical methods are available. The WFE predictions show excellent agreement with analytical solutions. For complicated structures (e.g., laminated panels, honeycomb-cored panels, and composite cylindrical shells), analytical solutions are difficult. Due to the use of the FE method, the geometry of arbitrarily complex structures can be captured straightforwardly. The full power of commercial FE packages and element libraries can be utilised. It is straightforward and efficient to use the WFE method, which provides accurate predictions at low computational cost.

Vibration and Structural Acoustics Analysis

In order to make it easy for developers and technology end-users to follow the latest developments and news in the field, this book collects into a single volume selected, extended, updated and revised versions of papers presented at the ...

Vibration and Structural Acoustics Analysis

Author: C.M.A. Vasques

Publisher: Springer Science & Business Media

ISBN: 9789400717039

Page: 327

View: 978

Vibration and structural acoustics analysis has become an essential requirement for high-quality structural and mechanical design in order to assure acoustic comfort and the integrity, reliability and fail-safe behavior of structures and machines. The underlying technologies of this field of multidisciplinary research are evolving very fast and their dissemination is usually scattered over different and complementary scientific and technical publication means. In order to make it easy for developers and technology end-users to follow the latest developments and news in the field, this book collects into a single volume selected, extended, updated and revised versions of papers presented at the Symposium on Vibration and Structural Acoustics Analysis, coordinated by J. Dias Rodrigues and C. M. A. Vasques, which was organised as part of the 3rd International Conference on Integrity, Reliability & Failure (IRF’2009), co-chaired by J. F. Silva Gomes and Shaker A. Meguid, held at the Faculty of Engineering of the University of Porto, Portugal, 20-24 July 2009. These papers where chosen from the more than 60 papers presented at the conference symposium. Written by experienced practitioners and researchers in the field, this book brings together recent developments in the field, spanning across a broad range of themes: vibration analysis, analytical and computational structural acoustics and vibration, material systems and technologies for noise and vibration control, vibration-based structural health monitoring/evaluation, machinery noise/vibration and diagnostics, experimental testing in vibration and structural acoustics, applications and case studies in structural acoustics and vibration. Each chapter presents and describes the state of the art, presents current research results and discusses the need for future developments in a particular aspect of vibration and structural acoustics analysis. The book is envisaged to be an appealing text for newcomers to the subject and a useful research study tool for advanced students and faculty members. Practitioners and researchers may also find this book a one-stop reference that addresses current and future challenges in this field. The variety of case studies is expected to stimulate a holistic view of sound and vibration and related fields and to appeal to a broad spectrum of engineers such as the ones in the mechanical, aeronautical, aerospace, civil and electrical communities.

Asymptotic Modal Analysis of Structural and Acoustical Systems

This book describes the Asymptotic Modal Analysis (AMA) method to predict the high-frequency vibroacoustic response of structural and acoustical systems.

Asymptotic Modal Analysis of Structural and Acoustical Systems

Author: Shung H. Sung

Publisher: Morgan & Claypool Publishers

ISBN: 1681739887

Page: 124

View: 669

This book describes the Asymptotic Modal Analysis (AMA) method to predict the high-frequency vibroacoustic response of structural and acoustical systems. The AMA method is based on taking the asymptotic limit of Classical Modal Analysis (CMA) as the number of modes in the structural system or acoustical system becomes large in a certain frequency bandwidth. While CMA requires both the computation of individual modes and a modal summation, AMA evaluates the averaged modal response only at a center frequency of the bandwidth and does not sum the individual contributions from each mode to obtain a final result. It is similar to Statistical Energy Analysis (SEA) in this respect. However, while SEA is limited to obtaining spatial averages or mean values (as it is a statistical method), AMA is derived systematically from CMA and can provide spatial information as well as estimates of the accuracy of the solution for a particular number of modes. A principal goal is to present the state-of-the-art of AMA and suggest where further developments may be possible. A short review of the CMA method as applied to structural and acoustical systems subjected to random excitation is first presented. Then the development of AMA is presented for an individual structural system and an individual acoustic cavity system, as well as a combined structural-acoustic system. The extension of AMA for treating coupled or multi-component systems is then described, followed by its application to nonlinear systems. Finally, the AMA method is summarized and potential further developments are discussed.

Vibroacoustic Condition Monitoring

D.N. Engineering Stress Analysis Fenner , R.T. Engineering Elasticity Ford , Sir Hugh . FRS , & Alexander , J.M. Advanced Mechanics of Materials ...

Vibroacoustic Condition Monitoring

Author: Czesław Cempel

Publisher: Ellis Horwood Limited

ISBN:

Page: 212

View: 969

Vibration condition is a relatively new area of technology. This text opens with an outline of its origins and presents possible applications of the technique, showing the role of vibration diagnostics and vibration condition monitoring (VCM) during the machine running stage.

Acoustic Analyses Using MATLAB and ANSYS

This is the first book of its kind that describes the use of ANSYS(R) finite element analysis (FEA) software, and MATLAB(R) engineering programming software to solve acoustic problems.

Acoustic Analyses Using MATLAB and ANSYS

Author: Carl Q. Howard

Publisher: CRC Press

ISBN: 9781138747487

Page: 708

View: 674

This book describes the use of Ansys finite element analysis software and MATLAB® to solve acoustic problems. These range from simple textbook problems, to complex ones that can only be solved using FEA software. The book includes instructions on relevant mathematical modelling, and hints on the use of Ansys software. The MATLAB source code provides readers with valuable tools for doing their own validations, and is available for download. The book provides practical training in the use of FEA for basic modelling and solving acoustic problems

Foundation of Statistical Energy Analysis in Vibroacoustics

This book is a complete and up-to-date presentation of the statistical theory of sound including the reverberation theory in room acoustics.

Foundation of Statistical Energy Analysis in Vibroacoustics

Author: A. Le Bot

Publisher: Oxford University Press, USA

ISBN: 0198729235

Page: 352

View: 678

This book provides an in-depth study of the foundations of statistical energy analysis, with a focus on examining the statistical theory of sound and vibration. In the modal approach, an introduction to random vibration with application to complex systems having a large number of modes is provided. For the wave approach, the phenomena of propagation, group speed, and energy transport are extensively discussed. Particular emphasis is given to the emergence of the diffuse field, the central concept of the theory. All important notions are gradually introduced---making the text self-contained---to lead the reader to the ultimate result of `coupling power proportionality' and the concept of `vibrational temperature'. Further key topics include the analogy between thermodynamics and sound vibration. Applications are concerned with random vibration in mass--spring resonators, strings, beams, rods, and plates but also reverberation in room acoustics, radiation of sound, and sound response.

Developments in Engineering Computational Technology

Developments in Engineering FOR THE PARALLEL VIBRO Computational Technology . ... Introduction This paper considers vibroacoustic analysis techniques using ...

Developments in Engineering Computational Technology

Author: B. H. V. Topping

Publisher:

ISBN:

Page: 312

View: 466

Contains a selection of papers that were presented at The Fifth International Conference on Computational Structures Technology and The Second International Conference on Engineering Computational Technology, which were held in Leuven, Belgium from 6-8 September 2000.

Topics in Modal Analysis I Volume 7

This seventh volume of eight from the IMAC - XXXII Conference, brings together contributions to this important area of research and engineering.

Topics in Modal Analysis I  Volume 7

Author: James De Clerck

Publisher: Springer Science & Business

ISBN: 3319047531

Page: 349

View: 912

This seventh volume of eight from the IMAC - XXXII Conference, brings together contributions to this important area of research and engineering. The collection presents early findings and case studies on fundamental and applied aspects of Structural Dynamics, including papers on: Linear Systems Substructure Modelling Adaptive Structures Experimental Techniques Analytical Methods Damage Detection Damping of Materials & Members Modal Parameter Identification Modal Testing Methods System Identification Active Control Modal Parameter Estimation Processing Modal Data

Rotordynamics of Automotive Turbochargers

Rotordynamics of automotive turbochargers is dealt with in this book encompassing the widely working field of small turbomachines under real operating conditions at the very high rotor speeds up to 300000 rpm.

Rotordynamics of Automotive Turbochargers

Author: Hung Nguyen-Schäfer

Publisher: Springer

ISBN: 3319176447

Page: 362

View: 272

Rotordynamics of automotive turbochargers is dealt with in this book encompassing the widely working field of small turbomachines under real operating conditions at the very high rotor speeds up to 300000 rpm. The broadly interdisciplinary field of turbocharger rotordynamics involves 1) Thermodynamics and Turbo-Matching of Turbochargers 2) Dynamics of Turbomachinery 3) Stability Analysis of Linear Rotordynamics with the Eigenvalue Theory 4) Stability Analysis of Nonlinear Rotordynamics with the Bifurcation Theory 5) Bearing Dynamics of the Oil Film using the Two-Phase Reynolds Equation 6) Computation of Nonlinear Responses of a Turbocharger Rotor 7) Aero and Vibroacoustics of Turbochargers 8) Shop and Trim Balancing at Two Planes of the Rotor 9) Tribology of the Bearing Surface Roughness 10) Design of Turbocharger Platforms using the Similarity Laws The rotor response of an automotive turbocharger at high rotor speeds is studied analytically, computationally, and experimentally. Due to the nonlinear characteristics of the oil-film bearings, some nonlinear responses of the rotor besides the harmonic response 1X, such as oil whirl, oil whip, and modulated frequencies occur in Waterfall diagram. Additionally, the influences of the surface roughness and oil characteristics on the rotor behavior, friction, and wear are discussed. This book is written by an industrial R&D expert with many years of experience in the automotive and turbocharger industries. The all-in-one book of turbochargers is intended for scientific and engineering researchers, practitioners working in the rotordynamics field of automotive turbochargers, and graduate students in applied physics and mechanical engineering.

Modeling Analysis and Optimization of Complex Vibroacoustic Systems with Micro perforates

For sound transmission control inside a duct, acoustic silencers are considered whose modeling is systematically tackled by the proposed numerical tools.

Modeling  Analysis  and Optimization of Complex Vibroacoustic Systems with Micro perforates

Author: Xiang Yu

Publisher:

ISBN:

Page: 199

View: 339

For sound transmission control inside a duct, acoustic silencers are considered whose modeling is systematically tackled by the proposed numerical tools. Reactive silencers with rigid internal partitions are studied for their parametric influences and noise attenuation mechanisms. With the introduction of MPPs as dissipative elements, a unit cell treatment is proposed to model the complex side-branch configuration, and investigations reveal the hybrid attenuation mechanism of such device, which combines the reflection and absorption effects. Benefiting from the modular nature of the sub-structuring approach, the size of the perforated hole and the perforation ratio can be optimized to strike a balance between the dissipative and reactive effect, for ultimately achieving a desired Transmission Loss (TL) within a prescribed frequency range. The calculation accuracy for both reactive and hybrid MPP silencers using the proposed approach have been confirmed with finite element method (FEM) simulations and experiments. For the tuning and optimization of a silencer, the broadband TL performance realized by a number of cascade-connected sub-chambers is investigated. A theoretical basis for the description of the overall system TL is presented. The characteristics of the sub-chambers, along with the understandings of influences of the parameters, provide guidelines for their optimizations, and a desired broadband performance is achieved by connecting sub-chambers with optimized TLs to tackle different frequency regions. Based on the sub-chamber strategy, a multi-level approach for the design, analysis and optimization of acoustic silencers with cascaded sub-chambers is proposed. Through numerical case studies and a retrofitted design of a mining truck muffler, the effectiveness of the proposed methodology is demonstrated, which greatly reduces the design variables and computational costs compared with global design and optimization.