VUMAT for Ogden hyperelasticity

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VUMAT for Ogden hyperelasticity

sajjadganjizadeh
hi I'm Msc student of mechanical engineering. I work on fatigue behavior of polymer.
 I wrote vumat for implementation of ogden hyperelastic . my vumat have good result for one element but  for more than 8 elements my model distort excessively. I model a cube and push it with a pressure boundry condition. I set zero the component of 4 5 6 (shear component) of stressNew in my vumat manually but when I run my vumat I see large shear stress in my model.
 does abaqus change stress outside the vumat?
 I use abaqus 6.14-2 fortran2013 and visual studio 2012.
 

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Re: VUMAT for Ogden hyperelasticity

engrsajadahmad
Check your mesh. May be your elements are more skewed than allowable limits.
In mesh module click verify mesh and check your elements.
*Engr. Sajjad Ahmad*

Assistant Professor
Department of Mechanical Engineering
Faculty of Engineering and Technology
International Islamic University Islamabad.
Tel:+92 51 9019956, Cell: +92-334-5085683
WhatsApp:+92-334-5085683
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RE: VUMAT for Ogden hyperelasticity

David Lindeman
In reply to this post by sajjadganjizadeh
You need to calculate the entire stress tensor based on the given deformation gradient.  You can’t assume that any of the components are zero.  See the Abaqus Theory sections on hyperelasticity.

Regards,

Dave Lindeman
Staff Scientist
Corporate Research Systems Laboratory
3M Center 235-3G-08
St. Paul, MN 55144
651-733-6383

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Subject: [EXTERNAL] [Abaqus] VUMAT for Ogden hyperelasticity



hi I'm Msc student of mechanical engineering. I work on fatigue behavior of polymer.

I wrote vumat for implementation of ogden hyperelastic . my vumat have good result for one element but  for more than 8 elements my model distort excessively. I model a cube and push it with a pressure boundry condition. I set zero the component of 4 5 6 (shear component) of stressNew in my vumat manually but when I run my vumat I see large shear stress in my model.

does abaqus change stress outside the vumat?

I use abaqus 6.14-2 fortran2013 and visual studio 2012.







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