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Nanshu Lu's picture

The effect of film thickness on the failure strain of polymersupported metal films

We perform uniaxial tensile tests on polyimide-supported copper films with a strong (111) fiber texture and with thicknesses varying from 50 nm to 1 μm. Films with thicknesses below 200 nm fail by intergranular fracture at elongations of only a few percent. Thicker films rupture by ductile transgranular fracture and local debonding from the substrate. The failure strain for transgranular fracture exhibits a maximum for film thicknesses around 500 nm.

Practical and graphical remarks about Moving Least Squares

I have had some time to write down an informal introduction to Moving Least Squares, from my coding perspective. It is supposed to be a condensation of experiences after some years of using it, although it does not contain any new theoretical aspect.

http://www.scribd.com/doc/19409754/yanrMLS

a fracture problem

  Dear everyone

modeling reinforced concrete cylindrical shell with abaqus

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Hello to everyone

I want to model a reinforced concrete cylindrical shell with abaqus using concrete damaged plasticity model. I want to model meridional and circumferential rebars in cylindrical shell in abaqus cae. I want to know which rebar geometry (angular or constant) I should use for modeling of both meridional and cirunferential rebars.Can I plot crack pattern for reinforced concrete shell in abaqus?

please guide me

 

Ganesh Soni's picture

First ply failure of composite panels using ABAQUS

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I am using ABAQUS Software for analysis of laminated composite plates (279X279X2.16) and (0/90)4s having 16 plies; trying to perform Buckling and Post buckling analysis using Static Rik’s algorithm.

Open Call for Journal Club Themes and Discussion Leaders

Attention all iMechanicians!  If you have a theme you would like to see in the Journal Club next year, please feel free to:

  1. post it here for discussion
  2. send it to me via email
  3. reccommend discussion leaders

Thanks in advance!

Konstantin Volokh's picture

Journal Club Theme of September 2009: Elasticity and Failure

Let us consider interaction of two atoms/molecules/particles. The reference distance between them corresponds to zero interaction force and zero stored energy. The interaction passes three stages with the increase of the distance. At the first stage the force increases proportionally to the increasing distance: the linear stage. At the second stage the force-distance relationship deviates from the linear proportionality: the nonlinear stage. At the third stage the force drops with the increasing distance: the separation or failure stage.

Pradeep Sharma's picture

The origins of electromechanical indentation size effect in ferroelectrics

The attached paper was recently accepted for publicaiton in Applied Physics Letters. Here we try to speculate on the origins of a type of electromechanical indentation size-effect. Although we have decent supporting evidence, I think that our assertions are still on the speculative side and hope that future experiments can shed further light on this.

Pradeep Sharma's picture

Revisiting Quantum Notions of Stress

I plan to submit the attached paper on quantum mechanical definition of stress in the next few weeks. Comments and feedback are welcome. Fair amount of work has been done on stress definition in the context of classical molecular dynamics (also attracting some controversies). In contrast, there appear to be several open issues in the quantum case. Hopefully, the attached paper provides a starting point.

FE routine for Viscoelasticity

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Hi,

Does anyone have a small strain FE viscoelasticity routine or code that I can use, prefreably in Fortran? Thanks.

Shriram

 

asit_rathod1's picture

WRC(welding Resarch code)

Dear

All

any body had idea about what is the WRC code anf from where it is available?i want to find one relation between Et(tangent modules)  ,Es(secant modules) and allowable comp.stress ?

if any one knows plz let me know..

Regards

ASit

asit_rathod1's picture

Non linear Iso chronous curve

Dear all

            Is there any method to finding out non linear Iso Chronous curve for alloy steel?..for diff time and at diff temp..

plz do needful

Regards

Asit Rathod

asit_rathod1@yahoo.com

Constitutuive modelling of viscoelastic materials

I am currently working on constictutive modelling of soft biological tissues, considering them as nonlinear viscoelastic materials. I am using the split form of energy density function i.e modelling separately the hyperelastc part and the visoelastic part. I am using Ogden formula for hyperelastic part and for the viscoelastic part, I am currently using the second and third invariants of stretch rate tensor.

asit_rathod1's picture

Iso Chronous curve

Thanks Vijay

                  for giving me guide lines but my altimate aim is to the finding of devlopment of iso chronous curve for creep buckling.and for that while studing nonlinear strees strain curve we know that as in non linear stage the what is the value of stress and strain at time T=0 and time T=t? is the any formula for the Et and Es in non linear stress and strain?...and which procedure for calulation foe Et and Es?

Regards

Asit Rathod

asit_rathod1's picture

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

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

Gouse's picture

Interface elements versus 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

ravimech04333's picture

Fracture Mechanics

Hello...

Can any one help me in how to solve J INTEGRAL for simple 2D geometries.Atleast can anyone help me where can i get PDF files on J integral... Plz its urgent its a part of Thesis...   Plz post your conmments at ravikumar_04333@yahoo.com

low velocity impact on composite plate

HI,

     I m working on low velocity impact on composite plate. Can anybody tell me after modeling plate in matlab how can i analysis it in  Ansys software?

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

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

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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.

Cai Shengqiang's picture

A theory of constrained swelling of a pH-sensitive hydrogel

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@gmail.com) for a description of the program.

Dear Omid and Sepehr

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

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

m_meisam's picture

Modeling concrete wall covered by FRP under blast load

Dear Guys

Is there any one that can help me for below questions?

1- Modeling FRP in abaqus CAE

2- Define interaction between FRP layer and concrete wall

Regards

M.Mojtahedpour

LG's picture

Some questions about wave propagation

Dear Sir

As we know, periodic signals are best analysed in the frequency domain while stochastic signals are usually more profitably analysed in the time domain. The analysis in the frequency domain usually concern only one signal while in the time domain often involves the comparison of several different signals.

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