Learning Forum

[Amin]

Hi, I would like to know how can I obtained the crack patterns of concrete in ANSYS Workbench for many sub-steps.

Knowing that I am using the following code, but it gives me only the cracks in the end of solution. I have only one step and 1500 sub-steps and I would like to see the cracks at15%, 30%, 50% and 75% of the maximum load

/Show, png

/ANG,1,

View,1,0,0,0

/Device, vector, on

set,1,last 

plcrack

[Yato]

You can do this by changing the substep of the set command. For example if you want al 50%:

 

set,1,750

[Amin]

Did You mean that I can do it by changing "last" to sub-step number that I need in set command?

[Yato]

Yes, try to do that.

[Amin]

It worked Well, Thank you for your help

Regards,

 

[Amin]

1- I would like to ask you another question, I would like to show the cracks in 30%, 45, 50, 75 and 100%. Using above code I need to duplicate the apdl command 5 times, how can I shows those cracks using only one command object?

2- I am also want to know how can I show the cracks when I have 3 number of steps?. I tried to see the cracks at 50% of load in step 1, 2 and 3 using the set command as mentioned bellow, but I get the crack only in step 1 and for 2 and 3 I get nothing. Knowing that the force in step 2 and 3 is higher then step 1.

SET,1,50

SET,2,50

SET,3,50

[Yato]

I'm not sure what's happening exactly. If you could attach the wbpz file it would be very helpful.

[Amin]

you can see the attached file 

 

[Yato]

I'm sorry, but I can not solve the problem, I recommend you open a new topic and you can find someone who can solve it

[Amin]

Thank you Yato for your help

[rickywugunawan]

Hi Amin. Did you solve this? I am facing the same problem as you now. 

Thanks.

 

Ricky

[Amin]

Hi Recky, 

You can see the crack pattren at each sub-step you want by changing word "last" in command 

set,1,last 

to the number of the sub-step you want. for example: if you have 1000 sub-steps and you want to see the cracks at sub-step number 500 you can just replace the 'last' by 500.

Another thing to see the cracks at the same time for differet sub-steps, I usually duplicate the command for each sub-step level that I want.

/SHOW,png

/ANG,1,

/VIEW,1,0,0,0 !Use these values to change the view

/DEVICE,VECTOR,ON

SET,1,last !Outputs final result set

 

PLCRACK

 

Good luck

Amin

[rickywugunawan]

Hi Amin, thank you so much for your response.

2- I am also want to know how can I show the cracks when I have 3 number of steps?. I tried to see the cracks at 50% of load in step 1, 2 and 3 using the set command as mentioned bellow, but I get the crack only in step 1 and for 2 and 3 I get nothing. Knowing that the force in step 2 and 3 is higher then step 1.

SET,1,50

SET,2,50

SET,3,50

Actually what I wanted to ask you is about this question that you asked about 3 load steps.

I currently have a model that has 40 load steps and different substeps on each step.
I use the same code that you provided, however when I try to change to SET,2,last, no cracks appear in the picture.

Below is the example :

1. the first load step is only until 15th substep

2. When I increase the substep (2nd Load step, 1st substep) the crack will disappear.

Have you solved this?

 

Thank you so much

Regards, Ricky

 

[Amin]

Hi Ricky,

Unfortunately, I didn't find solution to present the cracks as you mentioned. In my model, I tried to divid the applied force to many steps than include sub-steps for each step to overcome convergence issues. when I didn't get the cracks as you menstioned, I reduce the steps to one step and incrsease the sub-steps, as in the attached image. Using this way, I could see the cracks at each level. If you find a way to show the cracks, please share it with us.

Best regards

Amin.

 

[rickywugunawan]

I reduce the steps to one step and incrsease the sub-steps, as in the attached image. Using this way, I could see the cracks at each level. If you find a way to show the cracks, please share it with us.

 

Hi Amin,

If you reduce the load step to only one step. How do you observe the crack for the 2nd and the 3rd load step?
Do you just neglect them? 

Actually I found a way to present the cracks for the cyclic loading up to the last substep of the last load step. The result will be similar to this

Using this method

you change the step selection mode from "First" to "All"

 

However, something weird occurs if I use this setting. ANSYS seems to reduce my substep (from 30 to 10points). 

This is a problem because I will face a convergence problem before I finish my simulation.

 

Also, in the crack picture, you can see that it sets to step 1, although it already reached step 3

 

Regards,

Ricky

[Amin]

Hi Ricky,

In my case it wasn't a cyclicl loading. The load was monotonic increasing, load applied in one direction.

Thank yo for sharing the method. I tried it but I didn't get the crack at load steps at step 3 

[rickywugunawan]

Hi Amin, 

Forget my earlier post.

I finally found the method to display all the cracks on every load step. you set the general miscellaneous from no to yes, and store results at "equally spaced points", fill the value as you preferred. I recommend you to choose "equally spaced points" or else your data will be very big because it will save all data from your substeps. The tradeoff is that it will affect your stress, strain graph etc, so adjust the value as you desired.

 

Below is the PLcrack command that I use to display only the last substep of every step of the crack. Copy the last part as many as your load step

/SHOW,png

/ANG,1,

/VIEW,1,1,0,0   !Front view

!/VIEW,1,0,1,0  !Top view

 

/RGB,INDEX,100,100,100,0 !White BG

/RGB,INDEX,80,80,80,13

/RGB,INDEX,60,60,60,14

/RGB,INDEX,0,0,0,15

 

SET,1,1

/DEVICE,VECTOR,ON

 

/POST1

SET,1,, ,,, ,last

PLCRACK,0,0

 

/POST1

SET,2,, ,,, ,last

PLCRACK,0,0

 

/POST1

SET,3,, ,,, ,last

PLCRACK,0,0

 

/POST1

SET,4,, ,,, ,last

PLCRACK,0,0

 

Regards,

Ricky