This program written for use with MATLAB will grahically demonstrate the free and forced vibrations of a single degree of freedom systems. The user can set the properties of the system (mass, damping, stiffness) or the loading, and instantly obtain the response. Previous plots remain on the screen until the CLEAR button is pressed. Other plots such as the ransfer function, the impulse response function, and the fft of periodic loading are also displayed.To run:
1) load MATLAB,
2) change directory to where the file of sdof.m is located,
3) and issue the command sdof, without the m extension.
A powerful general approach to obtain solutions with the FFT method for undamped or lightly damped system is provided by the Exponential Window Method (EWM). Although this method has been used in signal processing and seismology, it is virtually unknown in structural dynamics. Here we provide two MATLAB programs to demonstrate the EWM in application to 1) a single degree of system subjected to step load; and 2) a continuous rod subjected to triangular pulse where the boundary conditions are stress-free at the top and displacement-fixed at the bottom of the rod.