LDM parameter on FATLOAD loadcollector

goodmorning everybody,

I'm running a fatigue analysis using FATLOAD to define the load,

inside the FATLOAD menu, a parameter called LDM is present but I don't know how to use it, because I don't know its meaning.

On the online help I found the formula linking the FEA stresses to the fatigue stresses, I know how to set SCALE & OFFSET parameters, but know nothing about LDM.

Can anybody help me understand the meaning of this parameter? is it just another scaling factor?

thanks

Find more posts tagged with

English

OptiStruct

Accepted answers

All comments

Rahul Rajan_21763

Hi,

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.

For ex:

Units of Load in FE = Load History Unit in the TestData, then LDM would be 1.

Hope this helps.

Regards

Rahul R

Altair Forum User

thanks Rahul,

another question, is it mandatory to keep the load time history (the one we load as a table when setting the TABFAT) in a value range between -1 and 1?

I mean, is it mandatory to introduce the time history as normalized between -1 and 1 or can we set directly the load history in Newtons?

regards

Altair Forum User

goodmorning everybody,

I'm running a fatigue analysis using FATLOAD to define the load,

inside the FATLOAD menu, a parameter called LDM is present but I don't know how to use it, because I don't know its meaning.

On the online help I found the formula linking the FEA stresses to the fatigue stresses, I know how to set SCALE & OFFSET parameters, but know nothing about LDM.

Can anybody help me understand the meaning of this parameter? is it just another scaling factor?

thanks

Can you share me with the information about how to set SCALE & OFFSET parameters? I checked other resources, but I still didn't get the meaning of these two factors.

Karthic_22061

Hi @federico,

goodmorning everybody,

I'm running a fatigue analysis using FATLOAD to define the load,

inside the FATLOAD menu, a parameter called LDM is present but I don't know how to use it, because I don't know its meaning.

On the online help I found the formula linking the FEA stresses to the fatigue stresses, I know how to set SCALE & OFFSET parameters, but know nothing about LDM.

Can anybody help me understand the meaning of this parameter? is it just another scaling factor?

thanks

Can you share me with the information about how to set SCALE & OFFSET parameters? I checked other resources, but I still didn't get the meaning of these two factors.

Rahul Rajan_21763

PFA pdf on FATLOAD and .fem file for your reference. As said in previous post use latest version.

Unable to find an attachment - read this blog

Karthic_22061

Hi @Rahul R,

Thank you for the response, these files are already there at help. Please share me some more fatigue .fem files for better understanding