Learning Forum

[Tianxiao Xie]

Hello,

I am doing some harmonic analysis with ansys harmonic response. In my case I need to define my material properties by APDL-Script. To make sure, that the APDL-Script really works correctly, I made a reference case where I use the material properties directly from Enginerring data. In the reference case I use the defaut material "structural steel", and in APDL-case I implement the structural steel in APDL-Script, which makes the enginerring data ignored. So the reference case and my case should now have the same properties. I also use the same boundary conditons for the example plate, with one side fixed and another side a force excitation. 

(Case with APDL-script to define material properties)

(Case with engineering data to define material properties)

Since I have the same materials and the same BCs, I should get the same results, but the deformation response looks totally different, can someone help me solving this problem? (I check the units, they seem to be correct)

regards

Tianxiao

 

[Erik Kostson]

 

 

Hi

One thing noted.

 

You should have all of the MP commands before the EMODIF.

 

Perhaps that might do it. Make sure also the units are the same in both models.

 

All the best

 

Erik

 

 

[Tianxiao Xie]

Hi Erik,

thanks for quick feedback.

I tried putting EMODIF behind all the MP, but there is still no change in results.

Units should be identical. The Emodul in APDL should have [MPa] as unit since [N/mm^2] is used. and Density is kg/mm^3, they are idential as in engineering data.

 

regards

Tianxiao

 

[Tianxiao Xie]

Strangely, when I make "emould" 10^3 times bigger to 2.0e8, I got the frequnce response plot with the same resonance frequency, like below, but the amplitude is 10^3 times smaller, as we can see from the plot. I have the same excitaion force, both 10N. Even if I made a mistake for the unit of Emodul, the Amplitude at resonance frequnce shouldn't 10^3 times smaller right?