🎉Community Raffle - Win $25

An exclusive raffle opportunity for active members like you! Complete your profile, answer questions and get your first accepted badge to enter the raffle.

Join and Win

What dose FATLOAD Parameter mean?

Altair Forum User

I am doing the fatigue practice and at my practice file.

I don't know what FATLOAD mean exactly. For example if our model today will subject a F=100N

At TID I know we need to set the TABLE to input and when I plot the .csv file

I seem it look like the Load Time History photo. So it this mean our total time is 2500 sec?

And the load have positive and negative for scale 1 and -1? (At here our model will subject 100N & -100N for 2500sec)

And the LDM I just can't know about it.

Finally what is mean for the SCALE? Because we have load time history we can see our load is for 1 and -1.

At here we set 3 so that means out load will scale for 3? (Final it will ill subject 300N & -300N for 2500sec)

image.png.8a2e352e7f7e4611414c3e9e43f88414.png

image.png.fe2c2cc1b84154a8fda06dc577a34f3b.png

Find more posts tagged with

English

OptiStruct

Accepted answers

All comments

Altair Forum User

I am doing the fatigue practice and at my practice file.

I don't know what FATLOAD mean exactly. For example if our model today will subject a F=100N

At TID I know we need to set the TABLE to input and when I plot the .csv file

I seem it look like the Load Time History photo. So it this mean our total time is 2500 sec?

And the load have positive and negative for scale 1 and -1? (At here our model will subject 100N & -100N for 2500sec)

yes,

LDM is a factor which takes of units between applied and time history.

The scale is also a factor which scales the load and time history

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

Altair Forum User

@Prakash Pagadala Thanks to your reply.

And I have also see your picture in the help.

But I still don't know about it. Do you have other explanation.

Really thanks for you.

Altair Forum User

HI,

It acts a scale factor between fea and time history units. If the units are different, provide the scale factor so that the results are normalized.

Altair Forum User

@Prakash Pagadala Really thanks to your apply!

So if our scale factor and time history units are different.

We need to change this value? (Does here have any value suggestion about if the factor is different from time history)

And the result will normalized? (What does here 'normalize' mean?)

Altair Forum User

HI @LKZ

It is used as a scale factor to normalize the finite element stresses/strains to obtain the stress/strain distribution due to a unit loading.

LDM is used to scale the units if the unit of loads in FEA and test are different.

It is best advised to maintain consistency of units between FEA and TEST and thereby keeping the value of LDM as 1.

Altair Forum User

@Prakash Pagadala Thanks to your reply.

So it recommend for 1 because it suggest to maintain our model's unit as the same as the FEA load unit.

If our model's unit is as same as the FEA load unit we don't need to change this value.

Here I think we need to pay attention about our model about its unit.

It should as the same as load. Then I don't need to change the value.

Altair Forum User

@LKZ

Yes, if the units are not consistent, this will lead to incorrect results and also playing with the scale factor is not advisable

Altair Forum User

How to solve this problem?

Karthic_22061

Hi @Prakash Pagadala

HI @LKZ

It is used as a scale factor to normalize the finite element stresses/strains to obtain the stress/strain distribution due to a unit loading.

LDM is used to scale the units if the unit of loads in FEA and test are different.

It is best advised to maintain consistency of units between FEA and TEST and thereby keeping the value of LDM as 1.

The test loads mentioned above.... is it the SN curve test data?

What you mean by FEA loads and test loads ?