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beytut

dynamic analyss of honeycomb elestomer

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Hi,

 

it depends how the geometry is modeled (homogenized solid elements or detailed modeling of cells with 2D shell elements):

-Crushable foams (Honeycomb) solid elements; Law 28: Honeycomb, Law 50: Crushable foam, Law 68: Cosserat medium

-Plastic shell elements; Law 36: tabulated elasto-plastic material, Law 65: Elastomer material,Law 66: Visco Elastic Plastic Piecewise Linear Material, Law 76: SAMP

 

 

beytut likes this

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Firstly Thanks for your reply

 

I am new for this field.  

 

Here is my model. made of PLA elastomer and Produced with 3d printer.  which prop and mat card ı need to use.   I try use law 65 with  shell(1) but I got some errors. 

Ekran Alıntısı.JPG

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Material law selection should be based on available test data for correlation (or at least available material properties). In general “An FE model should be as simple as possible, but as complex as necessary.”- in other words, choose the material model that captures the required physical behavior with the minimum amount of input parameters.

 

Since your model is shell based, law 65 is a good choice and according to the compatibility chart in Radioss help it should be compatible with shell 1. Can you share the model or .out file?

compatibility.jpg

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The issue was with property: the number of integration point through thickness parameter (N) was set to 0 (Global integration), which is not compatible with material law 65. More about this parameter from Radioss Help:

integration.jpg

 

Modeling approach should be reconsidered because the honeycomb cell walls are probably not intended to be hollow in reality. There are two options:

-shell mesh on midsurfaces extracted from solid. First, create the surfaces by Geom>surfaces>from FE, then create solid geometry by Geom>solid>bounding surfaces. Midsurfaces are extracted by Geom>midsurface. Use F11 panel for quick geometry editing.

-solid mesh using 3D>solid map on solid geometry

 

The following videos should be helpful:

 

Check the model attached where both mudsurfaces and solid geometry are extracted, ready for either modeling approach. Modeling with shells might not be the most appropriate as the cell wall thickness to length ration is high so thick shells or solid elements could be more suitable. 

Thick shells are used only when thickness to length ratio is between solid and thin shell recommended range:

 

0.jpg

When h/L is large, shear deformation is at its maximum importance and the user should use solid elements. When h/L is small, transverse shear deformation is not important and thin shell elements are the most effective choice.

 

honeycomb-edit.hm

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The model is unable to run because no load, BCs or simulation control is defined. 

I do not know what kind of analysis you want to perform. Besides, you would not learn how to do it if I did for you ;) 

Please go through free Radioss ebook to get started in explicit simulation.

Hypercrash manuals are attached below.

 

Also check following youtube channels:

Altair University. Altair India Student Contest. ELEATION By Apoorv Bapat

HW13-HyperCrash_Training_201702.pdf

HyperCrash_Introduction_12.pdf

Rahul R likes this

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4 hours ago, beytut said:

model is running when ı used law2 or law36. But for law 65 İ got error. 

 

 

Global integration (N= 0) is only compatible with Material Laws 1, 2, 22, 36, 43 and 60.

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