Questions about parameters in FATLOAD Load Collector

Elb

Hello everyone:

I've been trying to do the optistruct tutorial OS-T: 1340 Fatigue (Stress - Life) Method but I'm new in this area and  I have some questions about FATLOAD and its parameters.

1. What exactly is LDM and what realitonship has with the load of the subcase?
2. I've seen that loads for each subcase are respectively 1250 N and 1000 N. However both load histories are between 1 and -1 and with a scale of 3. Why is like that? Shouldn't it be with a scale of 1000 one and 1250 the other?
3. In the case that instead of a punctual load there's a pressure or moment in one subcase, load histories need to be scaled to N to be consistent or they can stay in the units of the subcase load (Nmm or N/mm^2)?.
4. How would you represent in the fatigue analysis static loads that contribute to the stress of the model but don't vary cyclicaly?

 

I appreciate your time answering them.

<?xml version="1.0" encoding="UTF-8"?>

<?xml version="1.0" encoding="UTF-8"?>

PrasannaK

Hi Eib,

 

You can refer to help for the information on FATLOAD (Attaching PDF of same).

Also refer to this post: 

 

Thank You

Unable to find an attachment - read this blog

Elb

Hello /profile/94428-prasannak/?do=hovercard' data-mentionid='94428' href='<___base_url___>/profile/94428-prasannak/' rel=''>@PrasannaK

Thank you for your answer.

I've read what you sent to me and the post and I think I kind of understood those parameters.

So actually the load history between 1 and -1 does not represent that the load is between 1 and -1 but between 1000 and -1000 (In my case). Is like if you multiply the load history by the magnitude of the load in the subcase right?

 

And Ldm is a scale factor to transform the magnitude  of any load in the subcase which is not a punctual load to the magnitude it would have if it were a punctual load and to match in units with the load history?