Here is a Matlab GUI script for calculating the natural frequency of a spring-mass system: sdof_fn.zip It can also be used to select total isolator stiffness for a given mass and intended natural frequency. It is version 1.1, so please let me know if there… Read more
Here is a Matlab script which calculates the H1 & H2 frequency response functions for a force and response time history pair. modal_frf.zip It is best suited for the case of random force excitation. It uses ensemble averaging. * * * Here is a Matlab… Read more
Question NASA-STD-7003A states wrt joint attenuation predictions that “….up to a maximum of three joints….” be used. I realize this maximum of 3-joint attenuation has been typically utilized in the industry. Does anyone know the basis behind this guideline (i.e. what’s the history and/or data… Read more
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
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