Fatigue Analysis

Sivaprakash_V

Hi,

I am using to Altair Hypermesh(optistruct) solver to perform Fatigue Analysis. I am a Beginner in fatigue Analysis.

I want to define the Load Time History under TABFAT card. Now I am stuck in the Load Time history creating process.

 Actually software identifies what values in X column and Y column. ?

As per My knowledge, X is Time in seconds and what is Y , it is a scale factor of load or Actual. what we put in y column.

I assume two cases : Assume my actual Load is 500 N

Case 1: X (TIME in seconds)      Y(LOAD in N or KN)

                    0                      0

                    1                      1

                    2                      2

                    .                       3

                    .                       4

                    5                      5
                    6                      0

 

Here I am used to created a load time history by using  scale Factor of the Load in the Y(Load) column.

For Example : If I Given the force value as 500 N in the Working Model, then I enter the Scale factor of the Load as 1, 2, 3....respectively.

Case 1: X (TIME )      Y(LOAD)

                    0                      0

                    1                      500

                    2                      1000

                    .                       1500

                    .                       2000

                    5                      2500

                    6                         0

  

Here I am used to created a load time history by using Actual Load Y(Load) column. 

For Example : If I Given the force value as 500 N in the Working Model, then I enter the actual load in the upcoming Time (seconds).

Based on the Two assumptions which one is correct or Correct me if I am Wrong.



Thanks & Regards,

Sivaprakash V,

Adriano_Koga

you should take a look at FATLOAD and TABFAT help sections.

https://help.altair.com/hwsolvers/os/topics/solvers/os/tabfat_bulk_r.htm

TABFAT contains only the Y values of your load history. FATLOAD has a multiplier, scale factor, that could be used to multiply your load history.

Additionally, this is related to your reference load case used into FATLOAD, so the actual final load, is a combination of all these.