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Problem is using static/riks option

Submitted by sushil on

I have some problem in defining the material properties using UMAT. I want to simulate the cubic stress-strain traction-sepration law. Solution doesn't converge after max load is applied (i.e zero slope of stress-strain plot). I am using riks solver. I have written my stress -strain relationship as below in UMAT file. Please tell me how to converge the solution even after zero slope of stress-strain relationship. Can i make my load factor(lambda) negative in riks option.

 

constraint on surface

Submitted by Anonymous (not verified) on

Hi everyone,

Do you know how to impose in abaqus that all the nodes of a specified surface have the same displacement on U1 for example without specifying a value. think about a traction test of a non homogeneous shell in which we want the edges to remain vertical.

I tried constraint, coupling, U1 but it fixes U1=0

thanks a lot,

Hichem

Ph.D. Research Assistantship in Multi-Scale/Multi-Physics Material Modeling at the University of Colorado, Boulder

Submitted by Franck Vernerey on

A graduate student researcher is sought to work on a theoretical and computational aspect of multiscale/ multi-physics material modeling (with an emphasis on biological materials and structures). The project’s envisioned outcome is to a better understanding of the relationship between the small scale physics and structures and the overall macroscopic properties of a material. This research has application in the design of new, smart material, or in the development of treatment for injuries and disease of biological tissues.

Large deformation elasticity and damping of individual carbon nanotubes in radial direction

Submitted by Majid Minary on

Carbon nanotubes as strong fibers in CNT-composites are subjected to large deformations in radial direction. They provide strength as well as structural damping in the composite. Despite being strong in the axial direction, CNTs are rather soft in the radial direction.

Challenges in modeling of CNT/polymer composites

Submitted by Kazem Yazdchi on

Many researchers have already used micromechanical modeling techniques such as Mori-Tanaka (M-T), Self-consistent methods and dilute inclusion models depending on volume fraction and shape of the inclusions, etc., to predict the overall mechanical properties of CNT/polymer composites.  However, we know that at nano scales the phenomenological behavior of material is different in comparison with micro or macro scales. Although the effects of waviness, interactions, agglomeration, etc.

I am so tired

Submitted by Changguo Xue on

Maybe I make some mistakes or a  bug in the website .

whenpress "post comment "buttom ,My comments were lost many time ,

And there only leave "I am a student of USTC.I am research in Biosensor base Microcantilver ." And these word I have deleted  a few hours ago .

I am so tired ,because this is my first time to post comment and I have not finished it several times .

Thank Prof Suo ,who invited my join it ,the iMechanica was best scientific community that I have seen .

""STUDY GROUP""

Submitted by Mahdi Kazemzadeh on

This is a great news for all students here in iMechanica! The formation of a study group which will focus on the basic concepts and the facts of daily research, the simple tools that any of us will need at a certain stage. Please see blow the formation of this idea and add your comment, it would be good to know other points of view as we can improve the initial idea step by step.