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Relation Between Et(tangent Modules) & Es(secant Modules) in non linear elastic plastic theory?

Submitted by asit_rathod1 on
research

dear all

            is there any formaula or any theory by i can make a relation for the tangent and secent modules in the plastic region of the stress strain curve?....and also how to find Et and Es for the Alloy steel?.. if any body knows any thing than let me know soon..

warm regards

Asit Rathod

asit_rathod1 [at] yahoo.com (asit_rathod1[at]yahoo[dot]com)

Interface elements versus continuum elements

Submitted by Gouse on
research
Interface elements
continuum elements

Hi,

I am modeling interface, its thickness is around 100 micron, I am modeling this problem in ABAQUS, my doubt is, can I use continuum elements like plane stress or plane strain to model this interface with conventional materail models available in ABAQUS or do I have to use interface elements with cohesive zone models. My main doubt is why should I use interface elements, whether plane or solid elements cannot handle interface, please can any body educate on this topic.

THank you

Regadrs

Gouse

Geometric factor for mode II stress intensity factor for a finite strip under under pure shear loading

Submitted by aysha.kalanad on
research

The geometric factor for mode I stress intensity factor for a finite strip under pure tensile loading is reported in Tada handbook as F(a/h) = 1.122 - 0.231(a/h) + 10.55*(a/h)^2 - 21.71*(a/h)^3 + 30.382*(a/h)^4 , but in the existing literature, I could not find such geometric factor for mode II stress intensity factor for a finite strip under under pure shear loading. Does anyone know such geometric factor for mode II stress intensity factor for a finite strip under under pure shear loading, if it is reported in the existing literature? or, if it is available in any unpublished sources?

Help with ABAQUS SIGINI subroutine

Submitted by Sherif Kamel on
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SIGINI Subroutine in ABAQUS

Dear ABAQUS Users,

I am trying to assign the initial stresses for a region in my model using the SIGINI subroutine. I learned some fortran programming skills the last week and I managed to open the file where the stresses that I retrieve from an Abaqus analysis and assign these stresses in Array using fortran commands.

Now I am stuck with the writing of the SIGINI subroutine where I have the corresponding stresses that I store in my Array to the corresponding NOEL and NPT.

A theory of constrained swelling of a pH-sensitive hydrogel

Submitted by Cai Shengqiang on
research
suo group research
hydrogel
gel

Many engineering devices and natural phenomena involve gels that swell under the constraint of hard materials. The constraint causes a field of stress in a gel, and often makes the swelling inhomogeneous even when the gel reaches a state of equilibrium. To analyze inhomogeneous swelling of a pH-sensitive gel, we implement a finite element method in the commercial software ABAQUS.  The program is attached here.  Contact Shenqiang Cai (shqcai [at] gmail.com) for a description of the program.

Dear Omid and Sepehr

Submitted by Arash Zamani on
research
xfem

I think a non-zero entry in the stiffness matrix doesn't necessarily imply dependence of ith DOF on the jth DOF. This is the case also for standard FEM (without any enrichments). For example for a quadrilateral 2D element the x component of displacement has interaction with y component at each node, but as we know, two independent values of translation in x and y directions can

Parabolic distribution of shear stress

Submitted by Huma Khalid on
research

Hi all

According to Timoshenko beam theory shear stress is distributed uniformly across the cross-section depth which is contrary to real distribution of shear stress i.e parabolic distribution. I know there is a shear adjusment factor (5/6 for rectangular cross-section) can solve this problem. But I don't know how can I utilize this adjustment factor in the beam formulation to get parabolic distribution.

Could anybody please help me?

 

Regards

Huma

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