How to apply pressure load in no. of cycles ? 1

[krishnagoud]

Hi all,

How can i apply a pressure load on a surface in no. of cycles ?

I have to use trapezoidal load form over 1 sec and it repeats for 700cysles at 1 Hz.

I can apply the load by using *Amplitude ((tabular method) for 1cycle as
*Amplitude, name=Amp-1
0, 0.1, 0.05, 1, 0.45, 1, 0.5, 0.1
1, 0.1
*Dsload, amplitude=Amp-1
<surface name>, P, 2e6

But I am wondering how can i apply the same load for 700 cycles at 1Hz.

Would please help me in this context?

Thanks in advance
Regards,
Krishna

 

[mrgoldthorpe]

If you use the default *AMPLITUDE option of TIME=STEP TIME, this sequence will be repeated in subsequent steps, provided the step time is equal to unity in each case.

 

[vumat721]

if you can represent it as a fourier series, you can use:
*Amplitude, definition=periodic

 

[krishnagoud]

Many Thanks for your replies...

@mrgoldthorpe
If i use time=step time, then i should use 700steps if i understand correctly ?

@vumat721
I will look at my load to represent in fourier series..

Thanks !

Regards
Krishna

 

[mrgoldthorpe]

Yes, you will need 700 steps. But you could put the commands for each step in one or a number of separate input files, then use *INCLUDE, eg:

*INCLUDE, INPUT=cycle_type1.inp
*INCLUDE, INPUT=cycle_type1.inp
*INCLUDE, INPUT=cycle_type1.inp
*INCLUDE, INPUT=cycle_type2.inp
*INCLUDE, INPUT=cycle_type1.inp
*INCLUDE, INPUT=cycle_type1.inp
*INCLUDE, INPUT=cycle_type1.inp
*INCLUDE, INPUT=cycle_type2.inp
** etc..

 

[vumat721]

if you're going do copy-paste, you may as well just create a really long amplitude definition and not create a confusing input deck with a thousand steps.

you could create the repeating amplitude pretty easily in excel without too much worry about typos, then export it to a comma-separated-values (csv) file which you can copy-paste into your input file.

 

[krishnagoud]

Thanks for you replies

/Krishna