Engineering Vibroacoustic Analysis E-Book

• Herausgeber: John Wiley & Sons
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 919

Veröffentlichungsjahr: 2016

Beschreibung

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.

Leseprobe

Table of Contents

Cover

Title Page

Wiley Series in Acoustics, Noise and Vibration

List of Contributors

1 Overview

1.1 Introduction

1.2 Traditional Vibroacoustic Methods

1.3 New Vibroacoustic Methods

1.4 Choosing Numerical Methods

1.5 Chapter Organization

References

2 Structural Vibrations

2.1 Introduction

2.2 Waves in Structures

2.3 Modes of Vibration

2.4 Mobility and Impedance

2.5 Bending Waves in Infinite Structures

2.6 Coupled Oscillators, Power Flow, and the Basics of Statistical Energy Analysis

2.7 Environmental and Installation Effects

2.8 Summary

References

3 Interior and Exterior Sound

3.1 Introduction

3.2 Interior Sound

3.3 Exterior Sound

3.4 Summary

References

4 Sound-Structure Interaction Fundamentals

4.1 Introduction

4.2 Circular Piston Vibrating against an Acoustic Fluid

4.3 Fluid Loading of Structures

4.4 Structural Waves Vibrating against an Acoustic Fluid

4.5 Complementary Problem: Structural Vibrations Induced by Acoustic Pressure Waves

4.6 Summary

References

5 Structural-Acoustic Modal Analysis and Synthesis

5.1 Introduction

5.2 Coupled Structural-Acoustic System

5.3 Simplified Models

5.4 Component Mode Synthesis

5.5 Summary

References

6 Structural-Acoustic Finite-Element Analysis for Interior Acoustics

6.1 Introduction

6.2 Acoustic Finite-Element Analysis

6.3 Structural-Acoustic Finite-Element Analysis

6.4 Coupled Structural-Acoustic Finite-Element Formulation

6.5 Summary

References

7 Boundary-Element Analysis

7.1 Theory—Assumptions

7.2 Theory—Overview of Theoretical Basis

7.3 Boundary-Element Computations

7.4 The Rayleigh Integral

7.5 The Kirchhoff–Helmholtz Equation

7.6 Nonexistence/Nonuniqueness Difficulties

7.7 Impedance Boundary Conditions

7.8 Interpolation

7.9 Applicability over Frequency and Spatial Resolution

7.10 Implementation – Software Required

7.11 Computer Resources Required

7.12 Inputs and How to Determine them

7.13 Outputs

7.14 Applications

7.15 Verification and Validation

7.16 Error Analysis

7.17 Summary

References

8 Structural and Acoustic Noise Control Material Modeling

8.1 Introduction

8.2 Damping Materials

8.3 Modeling Multilayer Noise Control Materials

8.4 Conclusion

References

9 Structural–Acoustic Optimization

9.1 Introduction

9.2 Brief Survey of Structural–Acoustic Optimization

9.3 Structural–Acoustic Optimization Procedures and Literature

9.4 Process of Structural–Acoustic Optimization

9.5 Minimization of Radiated Sound Power from a Finite Beam

9.6 Conclusions

References

Chapter 10: Random and Stochastic Structural–Acoustic Analysis

10.1 Introduction

10.2 Uncertainty Quantification in Vibroacoustic Problems

10.3 Random Variables and Random Fields

10.4 Discretization of Random Quantities

10.5 Stochastic FEM Formulation of Structural Vibrations

10.6 Numerical Simulation Procedures

10.7 Numerical Examples

10.8 Summary and Concluding Remarks

References

11 Statistical Energy Analysis

11.1 Introduction

11.2 SEA Background

11.3 General Wave-Based SEA Formulation

11.4 Energy Storage

11.5 Energy Transmission

11.6 Power Input and Dissipation

11.7 Example Applications

11.8 Summary

References

12 Hybrid FE-SEA

12.1 Introduction

12.2 Overview

12.3 The Hybrid FE-SEA Method

12.4 Example

12.5 Implementation and Algorithms

12.6 Application Examples

12.7 Summary

References

13 Hybrid Transfer Path Analysis

13.1 Introduction

13.2 Transfer Path Analysis

13.3 Hybrid Transfer Path Analysis

13.4 Vibro-Acoustic Transfer Function

13.5 Operating Powertrain Loads

13.6 HTPA Applications

13.7 Vibrational Power Flow

13.8 Summary

References

14 Energy Finite Element Analysis

14.1 Overview of Energy Finite Element Analysis

14.2 Developing the Governing Differential Equations in EFEA

14.3 Power Transfer Coefficients

14.4 Formulation of Energy Finite Element System of Equations

14.5 Applications

References

15 Wave-based Structural Modeling

15.1 General Approach

15.2 Theoretical Formulation

15.3 Wave-based Spectral Finite Element Formulation

15.4 Applications

15.5 Conclusion/Summary

References

Index

End User License Agreement

List of Tables

Chapter 01

Table 1.1 Approximate frequency range, computational requirements, and model and response resolution of vibroacoustic analysis methods

Chapter 02

Table 2.1

σ

m

values for free, clamped, and cantilevered beam modes

Chapter 03

Table 3.1 Acoustic boundary conditions

Table 3.2 Acoustic modes and natural frequencies [2, 3]

Table 3.2a

Table 3.2b

Table 3.3 Sound radiation from basic source and radiator cases [1, 2]

Chapter 04

Table 4.1 List of sound power radiation quantities and their interrelationships

Chapter 06

Table 6.1 Acoustic element types

Table 6.2 Plate element types

Table 6.3 Elastic boundary effects on cavity frequencies of station wagon

Chapter 07

Table 7.1 The number of interpolation frequencies required to reduce the error below 0.01 as a function of the number of active interpolation points

Table 7.2 Computation time as a function of number of processors

Table 7.3 Resonance frequencies and mode shapes for the cylinder (excluding modes with a nodal line at the cylinder’s center along its length)

Chapter 08

Table 8.1 Notional VEM material properties over frequency bands

Table 8.2 Notional complex resonance frequencies and loss factors

Table 8.3 The physical properties of the FG and Foam used in the double wall transmission loss studies of Figures 8.20 and 8.21

Chapter 09

Table 9.1 Optimization results and statistics

Table 9.2 Gain of objective function in (dB) for different optimal configurations

Chapter 10

Table 10.1 The gPC coefficients of the uncertain parameters

K

1

,

K

2

and

K

3

in Figure 10.5

Table 10.2 Sample dimensions;

a

: length,

b

: width and

h

: thickness; and material properties of the investigated orthotropic plates

Table 10.3 The identified gPC coefficients of the uncertain elastic parameters

Table 10.4 The coefficients of gPC of the first four eigenfrequencies for the orthotropic plate

Table 10.5 The nominal values of the first four eigenfrequencies,

, the probability with which these values occur, and corresponding standard deviations

Chapter 11

Table 11.1 Summary of modal density formulas

Chapter 13

Table 13.1 Predicted and measured powertrain mode frequencies and mode shapes [8]

Chapter 14

Table 14.1 Summary of differences between EFEA and flight test data for interior SPL

Table 14.2 Differences between the experimentally computed changes in the SPL due to treatment and the ones determined through the EFEA simulations

List of Illustrations

Chapter 01

Figure 1.1 Low-frequency (LF), mid-frequency (MF), and high-frequency (HF) approximate ranges in sound-pressure-level response in an automotive vehicle passenger compartment

Figure 1.2 Road noise sources in vehicle traveling at speed

V

: (a) Structure-borne noise in vehicle traveling on coarse road and (b) airborne noise in vehicle travelling on smooth road

Chapter 02

Figure 2.1 A longitudinal wave passing through a plate or beam (amplitudes highly exaggerated). As the material expands or contracts along the axis of the plate or beam, the Poisson effect contracts and expands the material in the transverse directions

Figure 2.2 A shear wave propagating through a plate or beam (amplitudes highly exaggerated). The wave propagates along the plate or beam axis, while deforming the structure transversely

Figure 2.3 A flexural, or bending wave propagating through a plate or beam (amplitudes highly exaggerated). As with pure shear, the wave propagates along the plate or beam axis, while deforming the structure transversely. Unlike pure shear, however, a bending wave causes the plate or beam cross sections to rotate about the neutral axis

Figure 2.4 Various wave speeds in a 10-cm-thick steel plate. The longitudinal and shear waves are nondispersive, and the bending waves are dispersive (vary with frequency). The thin plate wave speed becomes invalid at high frequencies where rotary inertia and shear resistance become important

Figure 2.5 Composite laminate stacks: left—uniaxial, right—quasi-isotropic

Figure 2.6 A typical sandwich panel cross section

Figure 2.7 Honeycomb core

Figure 2.8 Typical sandwich panel wave speeds

Figure 2.9 A stiffened aircraft fuselage

Figure 2.10 First four mode shapes of a simply supported beam. The dashed lines indicate the vibration antinodes, or locations of maximum deformation

Figure 2.11 First four mode shapes of a free beam. The dashed lines indicate the vibration nodes, or locations of zero deformation

Figure 2.12 Simply supported (left) and free (right) beam mode shapes at high mode order