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Preface | |
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Acknowledgements | |
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Basic Concepts | |
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Statics, dynamics and structural dynamics | |
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Coordinates, displacement, velocity and acceleration | |
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Simple harmonic motion | |
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Time history representation | |
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Complex exponential representation | |
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Mass, stiffness and damping | |
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Mass and inertia | |
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Stiffness | |
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Stiffness and flexibility matrices | |
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Damping | |
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Energy methods in structural dynamics | |
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Rayleigh's energy method | |
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The principle of virtual work | |
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Lagrange's equations | |
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Linear and non-linear systems | |
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Systems of units | |
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Absolute and gravitational systems | |
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Conversion between systems | |
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The SI system | |
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References | |
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The Linear Single Degree of Freedom System: Classical Methods | |
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Setting up the differential equation of motion | |
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Single degree of freedom system with force input | |
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Single degree of freedom system with base motion input | |
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Free response of single-DOF systems by direct solution of the equation of motion | |
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Forced response of the system by direct solution of the equation of motion | |
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The Linear Single Degree of Freedom System: Response in the Time Domain | |
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Exact analytical methods | |
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The Laplace transform method | |
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The convolution or Duhamel integral | |
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Listings of standard responses | |
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'Semi-analytical' methods | |
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Impulse response method | |
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Straight-line approximation to input function | |
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Superposition of standard responses | |
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Step-by-step numerical methods using approximate derivatives | |
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Euler method | |
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Modified Euler method | |
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Central difference method | |
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The Runge-Kutta method | |
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Discussion of the simpler finite difference methods | |
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Dynamic factors | |
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Dynamic factor for a square step input | |
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Response spectra | |
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Response spectrum for a rectangular pulse | |
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Response spectrum for a sloping step | |
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References | |
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The Linear Single Degree of Freedom System: Response in the Frequency Domain | |
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Response of a single degree of freedom system with applied force | |
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Response expressed as amplitude and phase | |
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Complex response functions | |
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Frequency response functions | |
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Single-DOF system excited by base motion | |
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Base excitation, relative response | |
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Base excitation: absolute response | |
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Force transmissibility | |
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Excitation by a rotating unbalance | |
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Displacement response | |
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Force transmitted to supports | |
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References | |
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Damping | |
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Viscous and hysteretic damping models | |
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Damping as an energy loss | |
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Energy loss per cycle - viscous model | |
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Energy loss per cycle - hysteretic model | |
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Graphical representation of energy loss | |
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Specific damping capacity | |
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Tests on damping materials | |
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Quantifying linear damping | |
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Quality factor, Q | |
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Logarithmic decrement | |
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Number of cycles to half amplitude | |
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Summary table for linear damping | |
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Heat dissipated by damping | |
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Non-linear damping | |
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Coulomb damping | |
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Square law damping | |
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Equivalent linear dampers | |
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Viscous equivalent for coulomb damping | |
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Viscous equivalent for square law damping | |
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Limit cycle oscillations with square-law damping | |
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Variation of damping and natural frequency in structures with amplitude and time | |
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Introduction to Multi-degree-of-freedom Systems | |
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Setting up the equations of motion for simple, undamped, multi-DOF systems | |
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Equations of motion from Newton's second law and d'Alembert's principle | |
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Equations of motion from the stiffness matrix | |
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Equations of motion from Lagrange's equations | |
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Matrix methods for multi-DOF systems | |
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Mass and stiffness matrices: global coordinates | |
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Modal coordinates | |
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Transformation from global to modal coordinates | |
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Undamped normal modes | |
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Introducing eigenvalues and eigenvectors | |
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Damping in multi-DOF systems | |
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The damping matrix | |
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Damped and undamped modes | |
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Damping inserted from measurements | |
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Proportional damping | |
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Response of multi-DOF systems by normal mode summation | |
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Response of multi-DOF systems by direct integration | |
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Fourth-order Runge-Kutta method for multi-DOF systems | |
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Eigenvalues and Eigenvectors | |
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The eigenvalue problem in standard form | |
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The modal matrix | |
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Some basic methods for calculating real eigenvalues and eigenvectors | |
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Eigenvalues from the roots of the characteristic equation and eigenvectors by Gaussian elimination | |
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Matrix iteration | |
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Jacobi diagonalization | |
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Choleski factorization | |
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More advanced methods for extracting real eigenvalues and eigenvectors | |
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Complex (damped) eigenvalues and eigenvectors | |
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References | |
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Vibration of Structures | |
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A historical view of structural dynamics methods | |
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Continuous systems | |
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Vibration of uniform beams in bending | |
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The Rayleigh-Ritz method: classical and modern | |
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Component mode methods | |
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Component mode synthesis | |
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The branch mode method | |
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The finite element method | |
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An overview | |
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Equations of motion for individual elements | |
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Symmetrical structures | |
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References | |
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Fourier Transformation and Related Topics | |
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The Fourier series and its developments | |
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Fourier series | |
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Fourier coefficients in magnitude and phase form | |
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The Fourier series in complex notation | |
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The Fourier integral and Fourier transforms | |
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The discrete Fourier transform | |
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Derivation of the discrete Fourier transform | |
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Proprietary DFT codes | |
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The fast Fourier transform | |
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Aliasing | |
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Response of systems to periodic vibration | |
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Response of a single-DOF system to a periodic input force | |
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References | |
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Random Vibration | |
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Stationarity, ergodicity, expected and average values | |
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Amplitude probability distribution and density functions | |
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The Gaussian or normal distribution | |
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The power spectrum | |
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Power spectrum of a periodic waveform | |
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The power spectrum of a random waveform | |
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Response of a system to a single random input | |
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The frequency response function | |
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Response power spectrum in terms of the input power spectrum | |
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Response of a single-DOF system to a broadband random input | |
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Response of a multi-DOF system to a single broad-band random input | |
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Correlation functions and cross-power spectral density functions | |
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Statistical correlation | |
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The autocorrelation function | |
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The cross-correlation function | |
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Relationships between correlation functions and power spectral density functions | |
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The response of structures to random inputs | |
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The response of a structure to multiple random inputs | |
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Measuring the dynamic properties of a structure | |
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Computing power spectra and correlation functions using the discrete Fourier transform | |
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Computing spectral density functions | |
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Computing correlation functions | |
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Leakage and data windows | |
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Accuracy of spectral estimates from random data | |
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Fatigue due to random vibration | |
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The Rayleigh distribution | |
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The S-N diagram | |
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References | |
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Vibration Reduction | |
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Vibration isolation | |
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Isolation from high environmental vibration | |
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Reducing the transmission of vibration forces | |
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The dynamic absorber | |
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The centrifugal pendulum dynamic absorber | |
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The damped vibration absorber | |
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The springless vibration absorber | |
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References | |
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Introduction to Self-Excited Systems | |
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Friction-induced vibration | |
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Small-amplitude behavior | |
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Large-amplitude behavior | |
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Friction-induced vibration in aircraft landing gear | |
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Flutter | |
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The bending-torsion flutter of a wing | |
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Flutter equations | |
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An aircraft flutter clearance program in practice | |
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Landing gear shimmy | |
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References | |
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Vibration testing | |
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Modal testing | |
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Theoretical basis | |
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Modal testing applied to an aircraft | |
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Environmental vibration testing | |
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Vibration inputs | |
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Functional tests and endurance tests | |
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Test control strategies | |
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Vibration fatigue testing in real time | |
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Vibration testing equipment | |
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Accelerometers | |
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Force transducers | |
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Exciters | |
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References | |
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A Short Table of Laplace Transforms | |
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Calculation of Flexibility Influence Coefficients | |
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Acoustic Spectra | |
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Index | |