admin Ideal random vibration has a normal distribution histogram. (In contrast, measured random vibration in the field may be nonstationary and thus vary from this ideal. ) Here are some resources: An Introduction to Random Vibration Integration of the Normal Distribution Paper Here is a software… Read more
Here are some useful references: Laplace Transform Table Partial Fractions Bessel Functions * * * Examples of the Laplace Transform as a Solution for Mechanical Shock and Vibration Problems: Free Vibration of a Single-Degree-of-Freedom System: free.pdf Response of a Single-degree-of-freedom System Subjected to a Unit… Read more
The mean filter is a simple sliding-window filter that replaces the center value in the window with the average (mean) of all the values in the window. The mean filter is intended as a lowpass filter which smooths the data. It may also be used… Read more
The scripts in integrate_th.zip integrate an acceleration time history to a velocity time history and/or a velocity time history to a displacement time history. The main script is: integrate_th.m The remaining scripts are supporting functions. Integrating acceleration to velocity typically causes a spurious offset in… Read more
(Image courtesy of A. Bhatia) Hotels have central heating, ventilation and air conditioning (HVAC) systems which generate noise that may disturb guests’ sleep. The noise propagates through ducts and room surfaces. Individual room air conditioning units may also cause unpleasant noise. The transmission paths in… Read more
These Matlab scripts calculate the steady-state response of a single-degree-of-freedom (SDOF) system to a sinusoidal force or base excitation: steady.zip – Tom Irvine
I recently flew from Spokane to Seattle, Washington on an Alaska/Horizon Air Bombardier Q400 aircraft, similar to the one in the above image. This model aircraft has two Pratt & Whitney Canada PW150A turboprop engines. I captured the following video during cruise using a Motorola/Android… Read more
Here is a paper for… Extending Steinberg’s Fatigue Analysis of Electronics Equipment Methodology to a Full Relative Displacement vs. Cycles Curve electronic_rd_n.pdf extending_Steinberg.pptx This paper also shows in a very roundabout way that “fatigue damage equivalence” between sine and random vibration occurs when the sine… Read more
This Matlab script calculates the one-sided, full amplitude FFT of an acceleration time history: FFT_VD.zip It gives the output FFTs in acceleration, velocity and displacement formats. It is useful for evaluating machine and pump vibration where there are distinct sine tones and harmonics. The main… Read more
Please see the following update: MDOF Frequency Response Function Natural Frequency & Damping Extraction including Modal Overlap. Post Link The half-power bandwidth method can be used to estimate the damping ratio and corresponding Q value from the frequency response function of a structure which has… Read more