Nonlinear Transient

Karthic_22061

Hi,

I am doing non-linear transient analysis with LGDISP,

In this case i need to study the dynamic effect (increase in stress) due to increasing the operating speed.

 

Given enforced displacement using TABLED1 & TLOAD1. In TABLED1 the use defined displacement is 0 to 40mm in 0 to 7.5 sec.

If i need to increase the operating speed. (i.e) 0 to 40mm displacement in 0 to 3 sec

 

Will my dynamic results vary ? or its independent of time?

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

Karthic_22061

Hi,

I found that varying the event time from 7.5sec to 3 sec does not vary the result. Found stress results are independent of event time...

 

Can you please share me a tutorial for impl dynamic.

 

 

Altair Forum User

Hi Karthik,

 

Can you share the tableD1 entries?

 

RIght now there is no tutorial available for Transient NL analysis. Except the attached.

Unable to find an attachment - read this blog

Karthic_22061

Hi Prakash,

Thank you for reply,

I have attached the TABLED1 content.

My question is if i need to attain the displacement of 40mm in 3 sec instead of 7.5 sec. (i.e) i need to study the dynamic effect (increase in stress when moment and inertia comes into play) due to increasing the operating speed.

Is this possible in nonlinear transient analysis

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

Altair Forum User

Hi Karthik,

 

Transient analysis will consider dynamic effects like inertia or damping. Let me check with a sample model with the same time depedent table and I will update you my findings.

Karthic_22061

Hi Prakash,

Thank you for your quick response

I tried a simple case and its considering the dynamic effects as per your previous post.

 

I still wonder how come a nonlinear transient takes dynamics into consideration but the simple direct transient does not ?

If non-linearity(Contact/ Geometric/ material )  is the difference between those two cases, how do they vary dynamically (inertia / momentum)

 

Please help me know the reason for it. Thank you once again

Altair Forum User

Karthik,

 

Can you share your comparision results and model files?

Karthic_22061

Hi Prakash,

Sure. Attached here

 

 

 

 

Karthic_22061

Hi Prakash,

 

Altair Forum User said:

Hi Kamalakar Rao,

 

Strain is a ratio of Change in length/original length. The same times 100 gives the percentage.

 

The result depends on your input. If your input is in %, the result output will be %

 

I need to plot the strain for my components that is yielding.

 

What should be the inputs for material property card (In Optistruct)  to get proper strain results? should i give the material yield value? or what else to be input

 

 

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

Altair Forum User

 

Karthic_22061

Hi Prakash,

Thank You for the support and guidance.

Salvatore

Hi, i used this example in order to set my non NL transient analysis.
I have added an Initial condition through parameter IC, and TIC but this condition have not been read by my model.

 

TIC have been setted with an initial displacement.

 

With Dload i applied Grav for all time of analysis.

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

Altair Forum User

Hi,

 

Can you please share the .out file and also please share the example you are referring.

Salvatore

Hi Prakash

 

i decided to open a new topin in order to explain betetr this problem.

 

I hope I have not broken any forum rules, and i hope that you could answere me just the same.

 

Thank you.