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Fatigue Vibration Ansys

Fatigue Vibration Ansys

Fatigue Vibration Ansys

(OP)
All,

We are desinging a frame that is to be attached to the bottom of a rail car.  This frame must withstand the following acceleration criteria:

Vertical
 1 ±0.2 g
 5.8 x 107 cycles
 
Lateral
 0 ±0.2 g
 5.8 x 107 cycles
 
Longitudinal
 0 ±0.2 g
 1.6 x 107 cycles
 
What is the best way to model this in ANSYS? I'm having trouble determining whether to use random vibration, response spectrum or even transient structural.

Thanks in advance.

RE: Fatigue Vibration Ansys

I'm not an ansys user, but these are sine vibration in each axis.  You can either subject your model to each axis separately to see the responses or you can use Dunkerly's equation as an estimate for one frequency.

 

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

RE: Fatigue Vibration Ansys

i'd model the static loadcases, you've possibly got 8 cases (+++, ++-, +-+, +--, -++, -+-, --+, ---), extract the stress peaks (same element, different cases), and do a fatigue analysis ...

RE: Fatigue Vibration Ansys

(OP)
Thanks for the responses.

I too had reached the conclusion of a static anlysis of all load cases.


I may have made this post in haste.
 

RE: Fatigue Vibration Ansys

you might want to look into canned fatigue analysis, eg ncode.

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