(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
Matthew 10:38 And he that taketh not his cross, and followeth after me, is not worthy of me. * * * Luke 9:23 And he said to them all, If any man will come after me, let him deny himself, and take up his cross… 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
Here is a good website for curve-fitting: zunzun From the website… Here you can curve fit and surface fit your 2D and 3D data online with a rich set of error histograms, error plots, curve plots, surface plots, contour plots, VRML, auto-generated source code, and… Read more
Both the Tabernacle and the Temple in Jerusalem had an inner room called the “Holy of Holies” which had a thick curtain or veil that separated it from the outer room. This inner room was God’s special dwelling place in the midst of his people.… Read more
This blog entry is a work-in-progress. Fatigue analysis can be performed in the time domain using rainflow cycle counting. This is an elegant, brute-force approach. One advantage of the time domain approach is that it tends to highlight the occurrences of peaks above 3-sigma for… Read more