Two random signals of particular interest are white noise and pink noise. White noise is a random signal which has a constant power spectrum for a constant frequency bandwidth. It is thus analogous to white light, which is composed of a continuous spectrum of colours.… Read more
I have never formally published any of my papers in a refereed journal or even in an engineering magazine, but others who have done so have referenced my tutorial papers. I am enclosing samples, which include conference papers, etc. – Tom Irvine * * *… Read more
Consider a lightly damped, single-degree-of-freedom system subjected to broadband random base excitation. The system will tend to behave as a bandpass filter. The bandpass filter center frequency will occur at or near the system’s natural frequency. The system response will thus tend to be narrowband… Read more
“Being humble means recognizing that we are not on earth to see how important we can become, but to see how much difference we can make in the lives of others” ― Gordon B. Hinckley
Image courtesy of Discount Tire Static Imbalance (left image) Occurs when there is a heavy or light spot in the tire that prevents the tire from rolling evenly and causing the tire and wheel to undergo an up-and-down motion. Dynamic Imbalance (right image) Occurs when… Read more
I recently came across a vendor that offers an isolator design using the concept in the figure above. The system is also referred to as the standard-linear solid model (SLS) by Zener, and is used as a simplified model for structural damping. It is a… Read more
The following Matlab script calculates the natural frequencies of a cylindrical shell which is enclosed at each end by a “shear diaphragm.” SD_SD_cylinder.m * * * Reference: Leissa, Vibration of Shells, NASA SP-288 See also: Vibrationdata Rings, Cylinders, Shells & Cones Page – Tom Irvine
I am relearning Fortran, including the features which have been added since I last used it some twenty years ago.Here is a method for compling a sample Fortran program NAME.F. This method checks for memory leaks.gfortran -fbounds-check -o NAME NAME.F ./NAMETom’s Fortran programs & related… Read more
The cepstrum function was originally developed for characterizing the seismic echoes resulting from earthquake and bomb explosions. It has also been used to determine the fundamental frequency of human speech, to analyze radar signal returns, and to evaluate machinery vibration. A cepstrum of time history… Read more
Cross-correlation is a measure of similarity of two waveforms as a function of a time-lag applied to one of them. Autocorrelation is the cross-correlation of a signal with itself. It is a time domain analysis useful for determining the periodicity or repeating patterns of a… Read more