Loads caused by earthquake to Skids

[KnutS]

Gentlemen (Ladies)

Well here's the problem; I have some skids, no big stuff, no HiSci or anything, just som skids/ cabinets,with some pipes/ tubing. Now they want to know if the equipment is useable or repairable after an earthquake.

The peak Acceleration occurs after 0,2 sec.
Mean Spectral Acceleration Horizontal; 1,81 (g).
Mean Spectral Acceleration Vertical ; 1,29 (g).'

Is it possible to get a usable evaluation to this problem by just adding these (peak) acceleration forces to the leg's connection points?

I use SolidWorks and CosmosWorks (premium package, this do not have the CosmosWorks module that handles this problem).

Any (easy) ideas will be appreciated..

Regards
KnutS

 

[tygerdawg]

I recently had to consult on something similar...completely out of my area of expertise. I was referred to a California state government website

http://www.oshpd.ca.gov

. From there I found a number of links to calculation documents. I used these to educate myself a little bit (then run as fast as I could in the opposite direction ).

TygerDawg
Blue Technik LLC
Virtuoso Robotics Engineering

http://www.bluetechnik.com

 

[zekeman]

Your data does not suggest an earthquake where the intensities are usually fractions of a g. Where does this data come from and what does "mean" mean in that context? If it the mean of a series of maximum g's felt for a series of quakes, then I would use 2 g's as the maximum in either the vertical or horizontal direction. If you could get a better description of the shock, then I think a better answer would be forhtcoming.
And when you do the problem, constrain the feet or bottom as it normally would be constrained and direct the g force at the center of mass of the structure.
As a final remark, I doubt that there is a structural problem with a skid due to an earthquake.
Buildings, on the other hand, are subject to damage due to the horizontal forces , which though modest in terms of g forces, are loading a significantly weaker structure than your skids.

 

[Cockroach]

Convert you peek accelerations to an added weight equivalent and then apply as a load in COSMOSWorks. Of course you are completely overlooking buckling by frequency analysis, but this would give you something.

Before getting jumped on in this forum, recognize this is simply a very idealistic way to get a number. It would be a starting point for your analysis.

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada