Constant load increment with LGDISP

jbinder89

Hello,

I am performing a large displacement nonlinear quasi-static analysis of a steel coupon under cyclic loading. I am applying displacement cycles using TLOAD1 and DLOAD, so that I can apply the entire loading protocol in a single subcase (cyclicing between 0.75 mm and 0). I would like to control the loading increment so that I have a smooth force-deformation hysteresis curve, but no matter what I try, the loading increment seems to increase beyond what I specified with NINC in NLPARM. For example, I have specified NINC=1000 (so that the increment should be 0.001), but in total my entire analysis has only about 150 increments. I have EXPERTNL turned off, and if I also turn off LGDISP, everything works fine, but once I turn LGDISP on, the increment seems to be automatically determined. Please advise! See attached for my model.

Thank you,

Justin

Unable to find an attachment - read this blog

Altair Forum User

Hi,

 

Thank you for sharing the file, I will check and update my findings with you soon. 

Altair Forum User

Hi @jbinder89

 

Is there a reason for using large displacement for this problem?

 

Since the strains are small, you can use small displacement formulation, instead.