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Incompressibility limit

Submitted by Breslavsky on

Dear All,

I want to calculate  the limit of the fraction (J-1)/(1-2*nu) when material approach to incompressibility, where nu is the Poisson's ratio and J is the third invariant of the Cauchy-Green deformation tensor. In this case J->1 and nu->0.5, but I can't find any reference, how J depends on nu.

Intuitively, this limit has to be a finite value, as it is known that (J-1)^2/(1-2*nu) -> 0 (under the assumption that there is no hydrostatic pressure). Thanks in advance for any suggestions

About indentation simulation with Ansys

Submitted by haolpk37 on
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Hi,all

 

       Recently,I met some problems about intendation simulation with Ansys.My simulation consider failure and large deflection.But the elements happen to distortion when the defelction became very large. So I have a confusion about how to handle the element distorted. Who have any idea about that? 

       My simulation is a quasi-static problem, How to use Ls-dyna to simulation this problem if the Ansys can't solve the element distortion efficient? Thanks a lot!

 

How safe are metal-on-metal hip implants? and are ceramic-on-ceramic safer? Or we will discover soon they are not?

Submitted by Mike Ciavarella on

Would you believe this story?

To me, that metal - on - metal had large friction, especially with the newest designs, it was clear from the old Sir Charnley studies in Leeds in 1950s published in his gold book. 

Anyway, when I looked at ceramic on ceramic joints, I also found evidence of increased friction.  Maybe ceramic debris is less toxic?

Please comment.  What can we do outside USA to improve the situation?

Michele Ciavarella 

Fixation and Mechanical Properties of Implanted Cartilage Replacements - An overview of three recently published papers

Submitted by Ali_Vahdati on

Partial- and
full-thickness cartilage lesions of the knee caused by trauma, disease or joint
instability are a common disorder affecting people of all ages. Implanted
cartilage replacements (ICR) have the potential to overcome the limitations of
conventional treatment methods and are a promising approach to restore
functionality of the joint. In spite of some success in engineering
cartilaginous tissue, inferior biomechanical and biochemical properties of ICR
compared to native articular cartilage (AC) and inadequate quality of fixation

defining a response spectrum in abaqus 6.10

Submitted by Lekshmi Dinachandran on

Hi,

I am trying to perform a response spectrum analysis of a tall tower. I work with abaqus 6.10, but i am unsure of how to define a spectrum. there is no spectrum radio button on the create amplitude menu... so i guess i have to edit the keywords.

does anyone have an example of how a spectrum can be defined? i'd be much grateful

Regards,

Lekshmi Remesh 

Energy formulations of nonlinear elasticity including electric / magnetic couplings

Submitted by liuliping on

Equilibrium theories for a continuum body may be formulated by either of the
following the classic paradigms: (1) We begin with the stress postulation (Cauchy’s formulation) and write down the kinematics, conservation laws, and
constitutive relations. In this way, one can obtain a system of field equations
which, presumably, can be solved upon specifying boundary conditions and
determine the equilibrium state of the body. (2) A second way is to start from
the energy postulation (Green’s