Total deformation not same (same settings)

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  • Last Post 12 March 2020
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Daniel97Yii posted this 11 March 2020

With the same settings (force, boundary condition, mesh size, element dimension, etc.), I get a different Total deformation, what could be the reason?
Attached are the results obtained. The upper picture with max deformation of 6.3801mm is more accurate if compared to experimental results (max deformation=5.07mm).

The bottom picture is less accurate (max deformation=3.31mm).

What could cause this problem and how to control the deformation so that it is close to the experimental result?

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Wenlong posted this 11 March 2020

Hi Daniel97Yii,

Please correct me if I am wrong: It looks to me that the top image has first-order elements and the second image has second-orders element. If that is the case, it could cause some difference, providing the mesh is not fine enough. 

To answer your second question, matching simulation results with the experiment has been a very broad topic and it could be infected by so many variables. Here is what I would check:

1. From representing the physical test point of view, does the model have accurate enough boundary conditions? Ex, simply supported? constrian rotation? Line loading? Point loading?

2. Does the material model represent the physical material well? Does Young's modulus match the experiment? Does the experiment show more complex behaviors like anisotropic behavior or material nonlinearity? If you are modeling a rebar-reinforced beam, does the model considers the interaction between the rebar and the concrete well´╝č

3. From the numerical modeling point of view, Is the mesh fine enough to provide enough accuracy? Is Large deflection turned on? 

These are just my thoughts from my experience, but hopefully, it can give you some ideas. 

Regards,

Wenlong Zhang

Daniel97Yii posted this 12 March 2020

Thanks for replying.

I found that after assigning "Concrete" in engineering material to the concrete bodies instead of the default "Structural steel", the Total Deformation I get becomes accurate. Meanwhile, the reinforcements are still assigned with the default "Structural steel". So, it seems that the problem is solved. 

Thanks again.

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