The attached 2-slide file shows a troublesome church roof (aren’t they all?) If you are knowledgeable in commercial building engineering, might you have a look?
BACKGROUND
• I find myself the perennial “property guy,” at our small church. (Roughly 50 members in post-covid days—money is...
Hello colleagues,
I am a veh. dynamics engr. with a question which is out of my field. Our local section of ASME (western suburbs of Chicago) has shown off Bernoulli principals to middle schoolers for years, and we are looking to improve our air supply. The demos include a "windstorm" lifting...
I'm involved in some tests to see if a large industrial assembly can be safely delivered by rail and/or truck. (The few motors & gearboxes have rotors in the 1000-3000 lb. range, and spherical or cyl. roller bearings. Mostly they will later end up in rather slow speed rotation (<100 rpm)...
I have a structure being driven into hardening supports due to thermal expansion or contraction. Test work shows that this changes its dynamic response. I'm modeling using PSTRES effects found using a static run at elevated temps, then a harmonic run (using the actual external operatinal...
Thanks.
I have a structure being driven into hardening supports due to thermal expansion or contraction. Test work shows that this changes its dynamic response. I'm modeling using PSTRES effects found using a static run at elevated temps, then a harmonic run (using the actual external...
When using COMBIN39s, what does a harmonic analysis do to solve? Linearize them using whatever slope it finds at zero load? Same with other nonlinears?
Yes, it is self-excited vibration. Wine glasses do it, railroad wheels do it (wheel squeal), violin strings, etc.
It will happen whenever the dynamic coefficient of friction is less than the static coef.
Say you have a box of cereal lying flat on a (stationary) grocery store checkout belt...
Yes, I've seen strain readings that are asymetric. Usually they have indicated that the loading pattern is also not zero centered. An extreme example would be the forks on a lift truck in bending (ie. the environment is heavily biased toward downward loading, with typically very little...
Fellow engineers,
I'm interested in variability of vehicle natural frequencies due to manufacturing differences on an assembly line.
I remember seeing an applicable paper cited a few years ago, but can't find the source. I think it was an SAE paper from the mid-1990's. (No, the SAE website...
Three further comments:
1) Given two mounts that appear to have the same stiffness and damping, the ability to sustain constant cycling is related to size (and therefore heat buildup per unit volume). For the EE's, this is loosely analogous to needing a 200K resistor, and decided whether to...