How to set up the shock analysis in Pro/Mechanica

[reyes163]

Could you help to set up the shock analysis for the attached ASY, I have set up the modal analysis and random analysis, actually when I use the use-defined step to get the von-Mises result, and I am not allowed to click the full result tab.
Here I need to run the shock test with 100G & 11ms, and need to evaluate whether it will fail or not. Appreciate very much for your help on this.

 

[Twoballcane]

I don't believe ProM can simulate a shock pulse. You may have to break down and calculate out the amplified G load and then apply the amplified G load in Pro M. Just make sure you have the correct densities for all of the material. So for a pulse of 0.011 sec this translates to 45 Hz, so anything that has Fn that is one octave away from 45 Hz will amplify may be as much as 1.7 x 100Gs.

Tobalcane
"If you avoid failure, you also avoid success."
“Luck is where preparation meets opportunity”

 

[seymours2571]

ProM can do a classic shock pulse within the time domain using the Dynamic Time analysis. The problem OP was having was the ProM would not provide von Mises stress results at the frequencies he explicity defined in the anlaysis tab.

I read a PTC KB article that stated there were some errors in calculating the VM Stress with respect to Dyanmic Random analysis, thus they do not provide any VM stress results in Dynamic Random simulations.

Ansys provides some clarity regarding the directional results from a Random Vibraiton Analysis:

"Since the directional results from the solver are statistical in nature they cannot be combined in the usual way. For example the X, Y, and Z displacements cannot be combined to get the magnitude of the total displacement. The same holds true for other derived quantities such as principal stresses."

However, Ansys uses some sort of special algorithm to produce VM Stress results. I am not sure why PTC cannot have ProM employ the same algorithm.

I wish PTC would do a better job on the documentation side of things with respect to ProM.

Steve


Stephen Seymour, PE
Seymour Engineering & Consulting Group

http://www.seymourecg.com

 

[Twoballcane]

That's probably why I don't use it and just do the hand calcs and get the max amplified acceleration load and apply it as a static load in ProM to retrieve the VM.

Tobalcane
"If you avoid failure, you also avoid success."
“Luck is where preparation meets opportunity”

 

[bobslo]

Hi guys

Try to use Independent mode of ProMechanica.

Bye.