Vibrationdata Matlab Page

Welcome to Vibrationdata Matlab Page

Dear Guest,

Writing tutorials and maintaining a website are expensive endeavors. I need your help to continue this effort. Your donation is appreciated.

Support Vibrationdata

Thank you for your support.

Sincerely, Tom Irvine
Email: tom@irvinemail.org

Tutorials

Power Spectral Density Calculation via Matlab: psd_mat.pdf
Guest tutorial submitted by Bob Light.

Classic Pulse Base Input Shock Analysis	Matlab Scripts
Response of a Single-degree-of-freedom System Subjected to a Half-sine Base Excitation	halfsine.m time_calc.m SDOF_base_animation_function.m sbase.pdf
Response of a Single-degree-of-freedom System Subjected to a Versed-sine Base Excitation	versed_sine.m versed_time_calc.m sbase_versed_sine.pdf
SDOF response to a terminal sawtooth base input.	terminal_sawtooth.m terminal_sawtooth_time_calc.m terminal_sawtooth.pdf
SDOF response to a wavelet base input.	sdof wavelet.m sbase_wavelet.pdf
SDOF response to combined sinusoidal force and base excitation.	sdof_force_accel.m sdof_force_accel.pdf
SDOF response to unit step force	unit_step_force.m force_unit_step.pdf
TWO-DOF response to applied force excitation.	two_dof_force_sine.m gencoord.pdf
TWO-DOF response to a wavelet base input.	twodof wavelet.m twodof_wavelet.pdf

Additional Shock Analysis Matlab Scripts

SRS Matlab Script (Kelly-Richman & Smallwood) srs.m

Supporting functions:
srs_coefficients.m
enter_time_history.m

find_max.m
fix_size.m

srs_intr.pdf

DS_SRS1.pdf

SRS via convolution srs_conv.m

Time history response of a single-degree-of-freedom system to an arbitrary acceleration base input via a digitial recursive filtering relationship. arbit.m

Supporting function:
srs_coefficients_avd.m
plot_peak_histogram.m
plot_TH.m
plot_histogram.m
enter_time_history.m

Tripartite Shock Response Spectra Plot srs_tripartite.zip

This script demonstrates how an SRS can be calculated from a time history using an FFT as an intermediate step.
srs_from_fft.m

Supporting functions:

sdof_base_accel_transfer.m
enter_time_history.m

full_FFT_core.m
fix_size.m

Mean filter method for removing saturation with optimization. mean_filter_saturation.m

Supporting functions
enter_time_history.m
mr_SRS.m

SRS plotting function SRS_plot.m

Interpolate an SRS function. interp_SRS.m

Shock pulse effective duration per MIL-STD-810F shock_effective_duration.m

progressbar.m

Waveform reconstruction via wavelets. waveform_reconstruct.m

wgen.m

wavelet_reconstruction.pdf

Scale a wavelet table to match an SRS specification. wavelet_scale_SRS.m

wqsrs.m

werror.m

Time history from a wavelet table. th_from_wavelet_table.m

SRS amplitude conversion utility srs_rel_disp.m

Fouier Transforms	Matlab Scripts
Fourier transform	fourier.m Supporting functions: find_max.m fix_size.m plot_TH.m plot_PSD.m mean_removal_Hanning.m enter_time_history.m progressbar.m
Inverse Fourier transform	invfourier.m
One-sided, Full-amplitude FFT	full_FFT.m Supporting function: full_FFT_core.m fix_size.m find_max.m enter_time_history.m fft.pdf
Waterfall FFT	waterfall_FFT.m Supporting function: waterfall_FFT_time_process.m waterfall_FFT_advise.m waterfall_FFT_time_freq_set.m waterfall_FFT_core.m waterfall_FFT_plots.m fix_size.m enter_time_history.m solid_motor_oscillation.pdf
Zoom FFT of a time series.	zoomFFT.m zoomFFT_plot.m zoom_fft.pdf zoomFFT_example.pdf d9p5.txt
Interpolation of a time history via its Fourier transform	interp_fourier.m

Signal Processing Matlab Scripts

Time History, PSD, SRS & SPL Statistics & Plotting signal_stats.m

Supporting functions:

differentiate_function.m

plot_histogram.m

coordinates_ss.m

coordinates_ss_scale.m

octaves.m

PSD_octave.m

plot_peak_histogram.m
signal_stats_TH.m
signal_stats_SRS.m
signal_stats_SPL.m
signal_stats_PSD.m

Multi-function signal processing script for time histories signal_functions.m

signal_function_extract.m

signal_function_stats.m

Integrate time history via the trapezoidal rule. integrate_th.zip

This script corrects an acceleration signal so that its corresponding velocity and displacement time histories are stable and oscillate about the zero baseline disp_correction.m

enter_time_history.m
velox_correction_d.m Butterworth_filter_function.m differentiate_function.m integrate_function.m
half_cosine_fade.m
cubic_spline_function.m
fix_size.m

Differentiate a time history. differ.m

Calculate the standard deviation time history from an instantaneous time history std_dev_th.m

Determine the natural frequency and damping of a transient waveform using time history synthesis sinefdam.m
sf_engine.m

Determine the natural frequency of a sinusoidal waveform using time history synthesis sinefind.m
sfa_engine.m

Extract Time History Segment extract.m

Track frequency and amplitude for a sine sweep sine_sweep_spectral.m

Find phase angle between two signals for sine sweep excitation sine_sweep_spectral_phase.m

Auto-correlation of two signals.
The Matlab Signal toolbox is not required.
auto_correlation.m

progressbar.m

Cross-correlation of two signals.
The Matlab Signal toolbox is not required.
cross_correlation.m

Aliasing frequency calculator aliasing.m

Remove pure tone noise from a signal. Can be used to remove 60 Hz and harmonic noise.
This method uses a time domain method curve-fitting method. It is precise but may take a "long" computational time. remove_noise_frequency.m

sfa_engine_60.m

Cubic spline
cubic_spline.m

Relative displacement between two displacement time histories relative_displacement.m

Signal Generation	Matlab Scripts
Generation of time history signals: 1=sine 2=cosine 3=damped sine 4=sine sweep 5=white noise 6=terminal sawtooth pulse 7=half-sine pulse 8=versed sine pulse 9=wavelet	generate.m Supporting functions: plot_histogram.m sweep.m white.m Butterworth_LP_filter_function.m filter_coefficients.m apply_filter.m
Generate a white noise time history where the user specifies the standard deviation and kurtosis. The skewness is approximately zero.	white_kurtosis.m progressbar.m
Generate a white noise time history where the user specifies the standard deviation, skewness and kurtosis.	white_kurtosis_skewed.m Supporting functions: plot_histogram.m progressbar.m
Generate a time history with kurtosis > 3. The corresponding histogram has a shape similar to a witch hat.	witch.m

Filtering	Matlab Scripts
Butterworth Sixth Order Filter, Transfer Function	BH.m filter.pdf REFILT.pdf
Bessel Filter, Transfer Function	Bessel_H.m
Butterworth Sixth Order Filter	Butterworth_filter.m Supporting functions: enter_time_history.m filter_coefficients.m apply_filter.m
Bessel Filter via Fourier transform	fourier_filter_Bessel.m Bessel_Transfer.m
Butterworth Sixth Order Filter via Fourier transform	fourier_filter.m Butterworth_Transfer.m
Mean filter of a time history	mean_filter.m

Sine Vibration	Matlab Scripts
Sine Vibration Response Spectrum (VRS)	sine_vrs.m
Time history response of an SDOF system to a sinusoidal base input	sine_base.m

Structural Dynamics: Beams & Rods	Matlab Scripts
Natural Frequencies and Mode Shapes of a Beam via the Finite Element Method, with two degrees-of-freedom per node. This program also calculates the participation factors and effective modal mass values. It allows for the addition of a point mass.	beam.m Functions: beam_data_entry.m local_stiffness.m local_mass.m assembly.m plot_modes.m mass_condense.m Generalized_Eigen.m beam.pdf
Natural Frequencies and Mode Shapes of a Beam via the Finite Element Method with six degrees-of-freedom per node. The beam elements may be in a three-dimensional frame.	beam_3D.m Functions: beam_3D_mass_condensation.m Generalized_Eigen.m beam_3D_modeplot.m User Guide beam_3D_guide.pdf
Normal modes & base excitation of a Cantilever Beam	cantilever_beam.m
Normal modes & base excitation of a Fixed-Free Rod	fixed_free_rod.m
Natural Frequencies and Mode Shapes of a Rocket Vehicle. The user must input a mass density file and an stiffness file. The stiffness file must be in terms of EI. A future version of this program will allow for joint compliance and a branch for a payload.	rocket_bending.m Functions: rocket_bending_data_entry.m rocket_local_stiffness.m rocket_local_mass.m assembly.m plot_modes.m

Structural Dynamics: Plates	Matlab Scripts
Natural Frequencies of a Circular Plate, Simply-supported, Bessel Function Solution	circular_SS.m
Natural Frequencies of a Circular Plate	circular_plate.m polarplot3d.m parse_pv_pairs.m
The Fundamental Frequency of an Isolated Circular Plate	circular_elastic.m
Natural Frequencies of a Annular Plate	annular_plate.m
The Fundamental Frequency of an Isolated Annular Plate	annular_elastic.m
The Natural Frequency of a Rectangular Plate Point-Supported at Each Corner	plate_corners.m pfunction.m

Structural Dynamics, Other Matlab Scripts

Free vibration of a single-degree-of-freedom system, exact method. free.m
free.pdf

Free vibration of a multi-degree-of-freedom system, exact method.
mdof_free.m

Generalized_Eigen.m
plot_legend.m
line_colors.m

Natural frequenices, mode shapes, participation factors and effective modal mass values of a two-degree-of-freedom system. two_dof.m

Natural frequenices and mode shapes of a three-degree-of-freedom system. three_dof.m

Natural frequenices and mode shapes of a multiple-degree-of-freedom system.
mdof.m
Generalized_Eigen.m

Natural frequenices and mode shapes of a multiple-degree-of-freedom system, reduced to a subset of dof per the user's input.
mdof_reduced.m
Generalized_Eigen.m

Mass Condensation (Guyan Reduction)
mass_condensation.m
Generalized_Eigen.m

Craig-Bampton Method mdof_CB.m

The Steady-State Frequency Response Function of a Multi-degree-of-freedom System Subjected to Harmonic Base Excitation two_dof_frf.m

The Steady-State Frequency Response Function of a Single-degree-of-freedom System Subjected to Harmonic Force Excitation sdof_force_frf.m

The Steady-State Frequency Response Function of a Multi-degree-of-freedom System Subjected to Harmonic Force Excitation two_dof_force_frf.m

two_dof_force_frf_alt.m

Natural Frequency of a Single-degree-of-freedom System ( GUI ) SDOF_freq.m
SDOF_freq.fig

Vibration Analysis of an Isolated Mass with Six-degrees-of-freedom six_dof_iso.m

Multi-degree-of-freedom system subjected to applied force, modal transient analysis

mdof_arb_force.m
progressbar.m
Generalized_Eigen.m

Multi-degree-of-freedom system subjected to applied force, modal transient analysis, reduced system
mdof_reduced_arb_force.m
progressbar.m

Matlab script for reduced system subjected to applied force, modal transient analysis, mass condensation mdof_masscon_arb_force.m

Assembly of mass and stiffness matrices with transformation matrix
mass_stiffness_assembly.m
Generalized_Eigen.m

Natural Frequencies of Spring Mass Systems in Series spring_mass_series.m
Generalized_Eigen.m

Torsional natural frequencies of a rod or shaft rod_torsional_fn.m

Three-dimensional coordinate transformation coordinate_transformation_3D.m

Roots of characteristic equations for structural dynamics vibration_roots.m

See also:

Matlab acoustics Page
Matlab linear algebra Page

Matlab_modal_transient_Page

Matlab_Newmark_Page

Matlab ode45 Page

Matlab RK4 Page

Matlab random vibration Page

Material Science	Matlab Scripts
Stress Corrosion Cracking: stress required to propagate a partial through-the-thickness crack-like discontinuity	stress_intensity.m

Animation Matlab Scripts

Animation of a single-degree-of-freedom system (spring mass system) subjected to sinusoidal base excitation with time history display. SDOF_base_animation.m

Animation of a single-degree-of-freedom system (spring mass system) subjected to sinusoidal base excitation. (old) SDOF_sine.m

Animation of seven SDOF systems subjected to common sinusoidal base excitation. SDOF_sine7.m

Plot Digitization	Matlab Scripts
Digitize SRS and PSD plots from image files, such as .jpg files.	loglog_digitize.m
Digitize log-linear plot.	loglin_digitize.m
Digitize SPL plot	digitize_SPL.m
Another digitization program.	digitize_plot.m

Additional Plot Utilities	Matlab Scripts
Surface Scatter Plot from matrix with three columns of data	surface_scatter_plot.m
Plot a large time history by taking only the max and min within successive intervals.	small_plot.m
Plot EasyPlot *.sav files in Matlab	EasyPlot_translator.m

Utilities Matlab Scripts

ASTM E 1049-85 (2005) Rainflow Counting Method rainflow.m

This progam sets up a coordinate table interactively for a PSD or SRS. coordinates.m

Convert Matlab data to ASCII text.
These programs use syntax similar to C/C++. data_convert.m

data_convert_21.m

Convert time in seconds to hours, min, sec format. hrminsec.m

Multi-format data input utility. data_input.m

Remove header lines from an external ASCII input file. header.m

UCI data conversion.

Generates a series of two-columns files (time & amplitude) from a UCI input file.
The first column is time(sec).
The additional columns are amplitude. uci.m

Principal moment of interia from a rotational inertia matrix. principal_moi.m

Add dB values for SPLs & PSDs. add_dB.m

Calculate the arc length of a half-sine wave.
These scripts demonstrate the use of the quad function with variable coefficients. arclength_sine.m

arc_function.m

Calculate the roots of a cubic polynomial. cubic_poly_roots.m

Interpolation	Matlab Scripts
Interpolate or extrapolate given two reference coordinates. Linear, Semilog and log options are included.	interpolate_coordinates.m
Logarithmic interpolation of a function.	intlog.m
Interpolate log-linear function.	int_semilog.m

Math & Geometry	Matlab Scripts
Calculate pi using a series expansion of cos(theta) and by applying the Newton-Raphson method. The goal is to find the root of cos(theta)=-1.	pi_nr.m
Calculate pi by determining the arclength of a quarter circle.	pi_arclength.m progressbar.m
Calculate pi by determining the area of a quarter circle. Simple grid point integration is used.	pi_gpi.m progressbar.m
Calculate the area of a quadrilateral which may be irregular from its coordinates	quadrilateral_area.m
Calculate the area of a triangle from its coordinates.	triangle_area.m

Statistics	Matlab Scripts
Normal tolerance intervals, upper limits	k_factor.m
Integrate the noncentral t-distribution	noncentral_t_distribution.m
Integrate the noncentral t-distribution, table format	noncentral_t_distribution_table.m
Integrate the student t-distribution.	integrate_t_distribution.m t_distribution.m
Integrate the chi-square curve.	integrate_chi_square.m chi_function.m
Integrate the normal distribution curve.	integrate_normal_distribution.m

Finance	Matlab Scripts
Loan calculation script for principal and interest	loan.m

Additional Shock Analysis	Matlab Scripts
SRS Matlab Script (Kelly-Richman & Smallwood)	srs.m Supporting functions: srs_coefficients.m enter_time_history.m find_max.m fix_size.m srs_intr.pdf DS_SRS1.pdf
SRS via convolution	srs_conv.m
Time history response of a single-degree-of-freedom system to an arbitrary acceleration base input via a digitial recursive filtering relationship.	arbit.m Supporting function: srs_coefficients_avd.m plot_peak_histogram.m plot_TH.m plot_histogram.m enter_time_history.m
Tripartite Shock Response Spectra Plot	srs_tripartite.zip
This script demonstrates how an SRS can be calculated from a time history using an FFT as an intermediate step.	srs_from_fft.m Supporting functions: sdof_base_accel_transfer.m enter_time_history.m full_FFT_core.m fix_size.m
Mean filter method for removing saturation with optimization.	mean_filter_saturation.m Supporting functions enter_time_history.m mr_SRS.m
SRS plotting function	SRS_plot.m
Interpolate an SRS function.	interp_SRS.m
Shock pulse effective duration per MIL-STD-810F	shock_effective_duration.m progressbar.m
Waveform reconstruction via wavelets.	waveform_reconstruct.m wgen.m wavelet_reconstruction.pdf
Scale a wavelet table to match an SRS specification.	wavelet_scale_SRS.m wqsrs.m werror.m
Time history from a wavelet table.	th_from_wavelet_table.m
SRS amplitude conversion utility	srs_rel_disp.m

Signal Processing	Matlab Scripts
Time History, PSD, SRS & SPL Statistics & Plotting	signal_stats.m Supporting functions: differentiate_function.m plot_histogram.m coordinates_ss.m coordinates_ss_scale.m octaves.m PSD_octave.m plot_peak_histogram.m signal_stats_TH.m signal_stats_SRS.m signal_stats_SPL.m signal_stats_PSD.m
Multi-function signal processing script for time histories	signal_functions.m signal_function_extract.m signal_function_stats.m
Integrate time history via the trapezoidal rule.	integrate_th.zip
This script corrects an acceleration signal so that its corresponding velocity and displacement time histories are stable and oscillate about the zero baseline	disp_correction.m enter_time_history.m velox_correction_d.m Butterworth_filter_function.m differentiate_function.m integrate_function.m half_cosine_fade.m cubic_spline_function.m fix_size.m
Differentiate a time history.	differ.m
Calculate the standard deviation time history from an instantaneous time history	std_dev_th.m
Determine the natural frequency and damping of a transient waveform using time history synthesis	sinefdam.m sf_engine.m
Determine the natural frequency of a sinusoidal waveform using time history synthesis	sinefind.m sfa_engine.m
Extract Time History Segment	extract.m
Track frequency and amplitude for a sine sweep	sine_sweep_spectral.m
Find phase angle between two signals for sine sweep excitation	sine_sweep_spectral_phase.m
Auto-correlation of two signals. The Matlab Signal toolbox is not required.	auto_correlation.m progressbar.m
Cross-correlation of two signals. The Matlab Signal toolbox is not required.	cross_correlation.m
Aliasing frequency calculator	aliasing.m
Remove pure tone noise from a signal. Can be used to remove 60 Hz and harmonic noise. This method uses a time domain method curve-fitting method. It is precise but may take a "long" computational time.	remove_noise_frequency.m sfa_engine_60.m
Cubic spline	cubic_spline.m
Relative displacement between two displacement time histories	relative_displacement.m

Structural Dynamics, Other	Matlab Scripts
Free vibration of a single-degree-of-freedom system, exact method.	free.m free.pdf
Free vibration of a multi-degree-of-freedom system, exact method.	mdof_free.m Generalized_Eigen.m plot_legend.m line_colors.m
Natural frequenices, mode shapes, participation factors and effective modal mass values of a two-degree-of-freedom system.	two_dof.m
Natural frequenices and mode shapes of a three-degree-of-freedom system.	three_dof.m
Natural frequenices and mode shapes of a multiple-degree-of-freedom system.	mdof.m Generalized_Eigen.m
Natural frequenices and mode shapes of a multiple-degree-of-freedom system, reduced to a subset of dof per the user's input.	mdof_reduced.m Generalized_Eigen.m
Mass Condensation (Guyan Reduction)	mass_condensation.m Generalized_Eigen.m
Craig-Bampton Method	mdof_CB.m
The Steady-State Frequency Response Function of a Multi-degree-of-freedom System Subjected to Harmonic Base Excitation	two_dof_frf.m
The Steady-State Frequency Response Function of a Single-degree-of-freedom System Subjected to Harmonic Force Excitation	sdof_force_frf.m
The Steady-State Frequency Response Function of a Multi-degree-of-freedom System Subjected to Harmonic Force Excitation	two_dof_force_frf.m two_dof_force_frf_alt.m
Natural Frequency of a Single-degree-of-freedom System ( GUI )	SDOF_freq.m SDOF_freq.fig
Vibration Analysis of an Isolated Mass with Six-degrees-of-freedom	six_dof_iso.m
Multi-degree-of-freedom system subjected to applied force, modal transient analysis	mdof_arb_force.m progressbar.m Generalized_Eigen.m
Multi-degree-of-freedom system subjected to applied force, modal transient analysis, reduced system	mdof_reduced_arb_force.m progressbar.m
Matlab script for reduced system subjected to applied force, modal transient analysis, mass condensation	mdof_masscon_arb_force.m
Assembly of mass and stiffness matrices with transformation matrix	mass_stiffness_assembly.m Generalized_Eigen.m
Natural Frequencies of Spring Mass Systems in Series	spring_mass_series.m Generalized_Eigen.m
Torsional natural frequencies of a rod or shaft	rod_torsional_fn.m
Three-dimensional coordinate transformation	coordinate_transformation_3D.m
Roots of characteristic equations for structural dynamics	vibration_roots.m
See also: Matlab acoustics Page Matlab linear algebra Page Matlab_modal_transient_Page Matlab_Newmark_Page Matlab ode45 Page Matlab RK4 Page Matlab random vibration Page

Animation	Matlab Scripts
Animation of a single-degree-of-freedom system (spring mass system) subjected to sinusoidal base excitation with time history display.	SDOF_base_animation.m
Animation of a single-degree-of-freedom system (spring mass system) subjected to sinusoidal base excitation. (old)	SDOF_sine.m
Animation of seven SDOF systems subjected to common sinusoidal base excitation.	SDOF_sine7.m

Utilities	Matlab Scripts
ASTM E 1049-85 (2005) Rainflow Counting Method	rainflow.m
This progam sets up a coordinate table interactively for a PSD or SRS.	coordinates.m
Convert Matlab data to ASCII text. These programs use syntax similar to C/C++.	data_convert.m data_convert_21.m
Convert time in seconds to hours, min, sec format.	hrminsec.m
Multi-format data input utility.	data_input.m
Remove header lines from an external ASCII input file.	header.m
UCI data conversion. Generates a series of two-columns files (time & amplitude) from a UCI input file. The first column is time(sec). The additional columns are amplitude.	uci.m
Principal moment of interia from a rotational inertia matrix.	principal_moi.m
Add dB values for SPLs & PSDs.	add_dB.m
Calculate the arc length of a half-sine wave. These scripts demonstrate the use of the quad function with variable coefficients.	arclength_sine.m arc_function.m
Calculate the roots of a cubic polynomial.	cubic_poly_roots.m

Welcome to Vibrationdata Matlab Page

Dear Guest,

Writing tutorials and maintaining a website are expensive endeavors. I need your help to continue this effort. Your donation is appreciated.

Support Vibrationdata Thank you for your support.

Sincerely, Tom Irvine Email: tom@irvinemail.org

Tutorials

Power Spectral Density Calculation via Matlab: psd_mat.pdf Guest tutorial submitted by Bob Light.

Classic Pulse Base Input Shock Analysis

Matlab Scripts

Response of a Single-degree-of-freedom System Subjected to a Half-sine Base Excitation

Response of a Single-degree-of-freedom System Subjected to a Versed-sine Base Excitation

SDOF response to a terminal sawtooth base input.

SDOF response to a wavelet base input.

TWO-DOF response to a wavelet base input.

Fouier Transforms

Matlab Scripts

Fourier transform

Supporting functions:

Inverse Fourier transform

One-sided, Full-amplitude FFT

Supporting function:

Waterfall FFT

Supporting function:

Zoom FFT of a time series.

Interpolation of a time history via its Fourier transform

Cubic spline

Signal Generation

Matlab Scripts

Generation of time history signals: 1=sine 2=cosine 3=damped sine 4=sine sweep 5=white noise 6=terminal sawtooth pulse 7=half-sine pulse 8=versed sine pulse 9=wavelet

Supporting functions: plot_histogram.m sweep.m white.m

Generate a white noise time history where the user specifies the standard deviation and kurtosis. The skewness is approximately zero.

Generate a white noise time history where the user specifies the standard deviation, skewness and kurtosis.

Supporting functions: plot_histogram.m progressbar.m

Generate a time history with kurtosis > 3. The corresponding histogram has a shape similar to a witch hat.

Filtering

Matlab Scripts

Butterworth Sixth Order Filter, Transfer Function

Bessel Filter, Transfer Function

Butterworth Sixth Order Filter

Bessel Filter via Fourier transform

Mean filter of a time history

Sine Vibration

Matlab Scripts

Sine Vibration Response Spectrum (VRS)

Structural Dynamics: Beams & Rods

Matlab Scripts

Natural Frequencies and Mode Shapes of a Beam via the Finite Element Method, with two degrees-of-freedom per node. This program also calculates the participation factors and effective modal mass values.

It allows for the addition of a point mass.

beam.m Functions: beam_data_entry.m local_stiffness.m local_mass.m assembly.m plot_modes.m mass_condense.m Generalized_Eigen.m

Normal modes & base excitation of a Cantilever Beam

Normal modes & base excitation of a Fixed-Free Rod

Natural Frequencies and Mode Shapes of a Rocket Vehicle. The user must input a mass density file and an stiffness file. The stiffness file must be in terms of EI.

A future version of this program will allow for joint compliance and a branch for a payload.

rocket_bending.m Functions: rocket_bending_data_entry.m rocket_local_stiffness.m rocket_local_mass.m assembly.m plot_modes.m

Structural Dynamics: Plates

Matlab Scripts

The Fundamental Frequency of an Isolated Circular Plate

The Fundamental Frequency of an Isolated Annular Plate

The Natural Frequency of a Rectangular Plate Point-Supported at Each Corner

Material Science

Matlab Scripts

Stress Corrosion Cracking: stress required to propagate a partial through-the-thickness crack-like discontinuity

Plot Digitization

Matlab Scripts

Digitize SRS and PSD plots from image files, such as .jpg files.

Digitize log-linear plot.

Digitize SPL plot

Another digitization program.

Additional Plot Utilities

Matlab Scripts

Surface Scatter Plot from matrix with three columns of data

Plot a large time history by taking only the max and min within successive intervals.

Plot EasyPlot *.sav files in Matlab

Interpolation

Matlab Scripts

Interpolate or extrapolate given two reference coordinates. Linear, Semilog and log options are included.

Logarithmic interpolation of a function.

Interpolate log-linear function.

Math & Geometry

Matlab Scripts

Support Vibrationdata

Thank you for your support.

Sincerely, Tom Irvine
Email: tom@irvinemail.org

Power Spectral Density Calculation via Matlab: psd_mat.pdf
Guest tutorial submitted by Bob Light.

Generation of time history signals:

1=sine
2=cosine
3=damped sine
4=sine sweep
5=white noise
6=terminal sawtooth pulse
7=half-sine pulse
8=versed sine pulse
9=wavelet

Supporting functions:

plot_histogram.m
sweep.m
white.m

Supporting functions: plot_histogram.m

progressbar.m

Natural Frequencies and Mode Shapes of a Beam via the Finite Element Method, with two degrees-of-freedom per node.

This program also calculates the participation factors and effective modal mass values.

beam.m

Functions:

beam_data_entry.m
local_stiffness.m
local_mass.m
assembly.m
plot_modes.m
mass_condense.m
Generalized_Eigen.m

rocket_bending.m

Functions:

rocket_bending_data_entry.m
rocket_local_stiffness.m
rocket_local_mass.m
assembly.m
plot_modes.m

Calculate pi using a series expansion of
cos(theta) and by applying the Newton-Raphson method. The goal is to find the root of
cos(theta)=-1.