Blast Analysis on Large Model with no Results!

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  • Last Post 15 January 2019
Abdallah26 posted this 10 January 2019

Hi,
I am doing a research on the effect of different soil types on the behavior of a structure under blast loading. I have created a small structure and put a TNT charge near one of the columns as shown in the first picture. I modeled a soil mas (highlighted in the model) around and underneath one of the footing only and not for the whole are in order to have a light analysis. the problem is that now after 24 hours of running I do not see any change in the energy graph. However, if I removed that mass of soil then change in energy occurs. I feel like this long analysis is going to nowhere. Help please! 

Best regards,
Abdallah

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SandeepMedikonda posted this 11 January 2019

Abdallah,

What does your solution output say? Is the time step dropping? Are you seeing any deformation with the soil in?

There seems to be something wrong in the setup/definitions. Can you post snapshots of the Analysis Settings, material information from Engineering Data and how the structure trees is setup?

Regards,
Sandeep
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Abdallah26 posted this 14 January 2019

Thank you Sandeep for your respond.

The analysis finished and there is no result. It says in the output file:" wrap-up time reached"

The material are: Structural steel and concrete form the general material defined by ANSYS. for Soil it is a copy from the concrete material but with soil properties numbers. Nothing special in the material.


Analysis settings:
1- structure tree


2-Analysis settings

Do you think the problem could happen because the eulerian domain is touching the borders of the soil?

Abdallah26 posted this 14 January 2019

I made the Eulerian domain larger than model by 10% and I ran the solution. I still do not see any drop in the energy, the problem still is not solved. the wired thing is that If I suppress the soil element, the energy changes and solution works.

SandeepMedikonda posted this 14 January 2019

Abdallah,

I think the problem is with your material. As a test, Try using the SAND material from the Explicit Material library (Engineering Data Sources). Does that help? 

I think you would need some kind of Equation of state to account for the hydrostatic behavior or non-linear/porosity behavior even which doesn't seem to be the case here with Elastic Soil.

Regards,
Sandeep
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Abdallah26 posted this 14 January 2019

I change the soil material to the SAND material but it did not work. It is so frustrating and I have tried everything.

SandeepMedikonda posted this 14 January 2019

Ok, Can you increase the number of Euler Elements to 5e5? There must be some leakage. Note that a Lagrange element size should be larger than Euler cell size for smoothest coupling. Typically a 2:1 ratio is recommended.

Regards,
Sandeep

Abdallah26 posted this 15 January 2019

I increased the Euler domain by 200% and still does not work. I uploaded the file, so can you please talk a look at it?

The file: https://ufile.io/sxost

Best regards,
Abdallah

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