Static vs transient analysis in ANSYS

[pegus]

Good day,

I would like to know the differences between a static and transient analysis in mechanics. I did research and found that the transient analysis adds the inertial and damping effects, but I don't really understand what this means.

I got this doubt, because we were analyzing the reaction forces in a lid that will be subjected to an impulse load, which goes form 1000 psi to 0 psi in 0.002 seconds. Our first though was to consider the load as a static and get the reaction in the supports, but one of our peers suggested approaching this with a transient analysis to see the dynamic response of this lid.

Approaching this problem with a transient analysis, are we going to obtain a different force reaction in the supports than doing it with a static analysis? or what outputs are we going to get with a transient analysis?

If you can also suggest literature to keep researching, it will be great.

Thanks in advance!

 

[DSB123]

If the load changes from 1000 psi to 0 psi in 0.002 Seconds then the loading is not a static loading by any means it is a transient load since it varies with time.

 

[CWB1]

A transient analysis shows reaction over time, a static analysis shows reaction at a single point in time. Static is often faster to run and if set up correctly can accurately show the max/min/best/worst case scenario, OTOH when life gets complicated you often need transient analysis to really understand what is going on.

 

[Denial]

If the load (or the load-change) is both sudden and non-impactive, then a good starting guess is that the dynamic effect of the load will be two times its static effect.[ ] To quote from my very old copy of Roark's Formulas for Stress and Strain:[ ] "the ordinary assumption that sudden loading causes twice as much stress and deflection as static loading is always a safe one to make".

 

[hacksaw]

It all depends on the dynamic response of the lid relative to your impact interval. I believe Roark's estimate applies in the case that the dynamic modes of the structure remain subcritical and the relative foot print of the impact area.