How can I add load in fatigue analysis?

Nicolò Lodini_21627

Hi, i'm trying to do a fatigue analysis, but i have a problem: values of the loads are updated from the static analysis or i have to indicate values?

example: i have a constant force of 1300 N in the static analysis, the value are directly imported by the software when i import the .fem?

Thanks

Adriano Koga_20259

Hi,

 

you can take a look at the help for some tutorials on fatigue.

 

In general, fatigue will use your base static analysis to assess your fatigue life. So in general, your static loads from  your linear static loadcases will be used on calculating fatigue. (you create a second loadcase, that takes into account your initial static loadcase.

In some cases you can use a unit load and then create an event that will have a multiplier factor over it.

So it really depends on how you model it.

Please, take a look at the tutorials on OptiStruct help. and I believe it would be helpful.

Nicolò Lodini_21627

Hi Adriano,

thanks for your answer, are you talking about the tutorial wich it is on the e-fatigue book?

I've followed the tutorial on that book, but if i change the SN material proprerties the results doesn't change, the damage is 0, so i think that there i a problem with the load (It's a multiaxial fatigue analysis).

Thanks for helping.

Adriano Koga_20259

Nicolò Lodini_21627 said:

Hi Adriano,

thanks for your answer, are you talking about the tutorial wich it is on the e-fatigue book?

I've followed the tutorial on that book, but if i change the SN material proprerties the results doesn't change, the damage is 0, so i think that there i a problem with the load (It's a multiaxial fatigue analysis).

Thanks for helping.

I'm actually talking about all these in the OptiStruct documentation/help:

Nicolò Lodini_21627

I've found the problem: if i put a negative value in the LoadHistiry it doesn't work. (EX: at time 2 the value is -1).