Modal Testing & Statistical Energy Analysis

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Modal Testing & Statistical Energy Analysis Page

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MODAL TESTING

An Introduction to Frequency Response Functions: frf.pdf

The Impulse Response Function: impulse_response_function.pdf
Response of a Single-degree-of-freedom System Subjected to an Impulse Force: force_impulse.pdf

The Impulse Response Function for Base Excitation: impulse_response_function_base.pdf
Nyquist and Nichols Plots: Nyquist_plot.pdf

The Steady-State Frequency Response Function of a Multi-degree-of-freedom System Subjected to Harmonic Base Excitation: mdof_FRF_base.pdf

Structural Dynamics Testing using an Impulse Force: structd.pdf
This tutorial also covers use of the exponential window.

Exponential Windows: expw.pdf. Guest tutorial submitted by
G. Weber.

Effective Modal Mass & Modal Participation Factors: ModalMass.pdf

The Fundamentals of Modal Testing: modal_fund.pdf
Frequency Response Function Measurements: FRF_measurements.pdf

Kijewski and Kareem, Analysis of full-scale data from a tall building in Boston: damping estimates: boston.pdf

Richardson, Derivation of Mass, Stiffness and Damping Parameters From Experimental Modal Data: derivation_modal.pdf

Okuma, Heylen, Sas, Identification of Rigid Body Properties of 3-D Frame Structure by MCK Identification Method: ident_MCK.pdf

See also: Transfer_Functions

MODAL DENSITY

Modal Density: mdens.pdf

Matlab Script: modal_density.m

STATISTICAL ENERGY ANALYSIS

Radiation & Driving Point Impedance of a Thin, Isotropic Plate: dp_impedance.pdf

Vibroacoustic Critical and Coincidence Frequencies of Structures: critical_frequency.pdf

Vibration Response of a Thin Cylindrical Shell to External Acoustic Pressure via Statistical Energy Analysis: SEA_cylindrical_shell.pdf
Matlab Scripts:
SEA_cylinder.m
SEA_plot.m
progressbar.m

Transmission loss through a single partition: single_partition.m

Transmission loss through a single partition using the plane wave method: single_partition_plane_wave.m

Fill factor for a payload fairing
fill_factor.m
octaves.m

Vibration Power Measurement using a Plate as a Reverberant Structure: VPthesis.pdf

Byam & Radcliffe, Statistical Energy Analysis Model and Connectors for Automotive Vibration Isolation Mounts: IsolMount.pdf

See also: Vibroacoustics

Bruel & Kjaer Booklets

Structural Testing 1: Mobility Measurement

Structural Testing 2: Modal Testing

Software	Executable	Source
Digital filtering using a Butterworth 6th order filter. The user must supply an input time history file. Both lowpass and highpass options are available.	filter.exe	filter.cpp
Fast Fourier transform (FFT) of a time history. The transform operates on a time series with 2^n points, where n is an integer. Also, corresponding inverse FFT.	fft.exe invfft.exe	fft.cpp invfft.cpp
Conventional Fourier transform of a time series with an arbitrary number of points.	fourier.exe	fourier.cpp
Zoom FFT of a time series.	zoomFFT.exe	zoomFFT.cpp
Cross-spectrum of two time histories. The output files may be used for modal test data analysis.	cross_spectrum.exe	cross_spectrum.cpp
Cross-spectrum of two time histories. The program generates H1 and H2 frequency response functions (FRFs), the coherence function, and the corresponding impulse response functions.	cross_spectrum_modal.exe	cross_spectrum_modal.cpp
This program generates a power transmissibility function for a single-degree-of-freedom subjected to a force input. The transmissibility dimension is: ( accel^2 / force^2 )	force_trans_modal.exe	force_trans_modal.cpp
This program performs a curve-fit on an acceleration spectral function resulting from an applied force. The main purpose is to determine the damping ratio. The spectral function may be: 1. acceleration PSD 2. acceleration Fourier magnitude 3. transfer function magnitude (accel/force)	bandwidth_damp.exe	bandwidth_damp.cpp
Driving point impedance of a thin plate, bending waves	dp_impedance.exe	-
Driving point impedance of a beam, longitudinal waves	dpi_beam.exe	-
Critical and Ring Frequencies of a Cylinder.	SEA_cylinder_parameters	-

Matlab	Script
Calculate frequency & impulse response functions from an input force and response amplitude time history.	frf_from_th.m Supporting Functions: fix_size.m frf_median_filter.m

Recommended Books

1. D.J. Ewins, Modal Testing: Theory and Practice

2. Lyon and Dejong, Theory and Application of Statistical Energy Analysis

3. L. Cremer and M. Heckl, Structure-Borne Sound

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