PM4sand

[19520010290]

Hello, I am encountering the following error during calculation after executing `updateMaterialStage -material 2-stage 1` when using PM4sand material and SSPquadUP units. I am unable to resolve it and urgently require your assistance. Many thanks in advance!

[STKO Team]

As you can see from the error, something is trying a division by 0.
Try to use an Elastic material instead of the PM4Sand. If the error disappers, then it means it has something to do with the PM4Sand. Probably some wrong parameters

[STKO Team]

Can you share your STKO model?

[19520010290]

Can you share your STKO model?

Right, I've just posted a new topic with the following content:Dear stko team, I am simulating a two-dimensional soil mass using PM4sand material and SSPquadUp elements. However, I encounter errors during the elastoplastic calculation. Despite extensive adjustments, the issue persists, compelling me to seek your assistance. Please find my model attached below. I would greatly appreciate your help. Thank you once again.

[19520010290]

Please reply to me here; I look forward to hearing from you.

[STKO Team]

This one works:

pm4sand.zip

(338.52 KiB) Downloaded 51 times

There were 2 issues:

• You forgot to put the tag of your PM4Sand material after the FirstCall argument in the setParameter command. The PM4Sand only processes the first argument if the second argument is equal to its tag:

  

  pm4sand.png (129.84 KiB) Viewed 1694 times

• Now you cannot use the initialStateAnalysisWrapper.
  Who wrote that class only allowed a few parameters to be passed to the wrapped material:

  

  InitWrapper.png (112.82 KiB) Viewed 1694 times

  Therefore, your call to update the FirstCall parameter was not called

[19520010290]

This one works:
pm4sand.zip

There were 2 issues:

• You forgot to put the tag of your PM4Sand material after the FirstCall argument in the setParameter command. The PM4Sand only processes the first argument if the second argument is equal to its tag:
  pm4sand.png
• Now you cannot use the initialStateAnalysisWrapper.
  Who wrote that class only allowed a few parameters to be passed to the wrapped material:
  InitWrapper.png
  Therefore, your call to update the FirstCall parameter was not called

Very well, Thank you, your response is both clear and insightful, and I've learnt a great deal from it. I'm sorry to trouble you again, but I now need to simulate the dynamic response of a two-dimensional saturated soil body, which is exceptionally thick. Previously, using the PDMY02 material, I found that the dynamic response at depths of several hundred metres did not meet expectations. Therefore, I wish to replace it with a constitutive model that better simulates saturated sandy soils at considerable depths. Do you have any constitutive models you would recommend? Additionally, you mentioned that the PM4sand material cannot utilise the initialStateAnalysisWrapper. However, I wish to employ this wrapper to achieve the initial geostress equilibrium process. This issue has been troubling me, hence my visit to the discussion forum in the hope of resolving it. Many thanks indeed. Wishing you all the best and looking forward to your reply.

[STKO Team]

Therefore, I wish to replace it with a constitutive model that better simulates saturated sandy soils at considerable depths. Do you have any constitutive models you would recommend?

You should understand what model you need in OpenSees (it's not about STKO).

Additionally, you mentioned that the PM4sand material cannot utilise the initialStateAnalysisWrapper. However, I wish to employ this wrapper to achieve the initial geostress equilibrium process.

Here https://asdea.eu/software/webinars/ you can find the webinar
#07 Construction Stage Analysis in STKO and OpenSees: Leveraging Incremental Multi-Point Constraints and the New Auto Constraint
Thats shows an alternative way of doing the same thing without the initial state wrapper

[19520010290]

Therefore, I wish to replace it with a constitutive model that better simulates saturated sandy soils at considerable depths. Do you have any constitutive models you would recommend?

You should understand what model you need in OpenSees (it's not about STKO).

Additionally, you mentioned that the PM4sand material cannot utilise the initialStateAnalysisWrapper. However, I wish to employ this wrapper to achieve the initial geostress equilibrium process.

Here https://asdea.eu/software/webinars/ you can find the webinar
#07 Construction Stage Analysis in STKO and OpenSees: Leveraging Incremental Multi-Point Constraints and the New Auto Constraint
Thats shows an alternative way of doing the same thing without the initial state wrapper

Right, I've got that covered. Thank you.

[STKO Team]

You're welcome