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Modeling contact in ABAqus

i am working on modeling hertzian contact (general and standard conact in abaqus). i want to know how to model contact between surfaces of my assembly.  i modeled it but it gives me error saying that my regions in the model are not connected.

How should I go about? is contact modeling different than just constraining the surfaces ? 

Reza khodaee's picture

Micro-plate's deflection

Hello

I'v been searching for micro-plate's deflection formulas.

Please help me in finding relations

Thanks 

"bending stress-strain curve" or "compression stress-strain curve"?

Hi 

I want to model the lightweight slab and since i do not have the material behaviour of the slab, i have to do testing. i was searching in internet and i got two different concept: "bending stress-strain curve" and "compression stress-strain curve". i do not know which one should i follow? and is there any difference?

Regards.

pflines's picture

puzzle in the asymmetric four-point-bend sepcimens.

HI, everyone,

 This is pflines, i am working on the mode I\II fracture toughness.

i want to use the asymmetric four-point-bend sepcimens to get the value of KI and KII,

 but did not found a clear formulation to caculate the KI and KII,

 anyone could help me?

convergence difficulty due to the stiffness degradation in Abaqus

Hello everybody

I am simulating hydraulic fracturing operation with Abaqus. I have used cohesive elements and also utilized viscous regularization to cope with convergence difficulty. However, the problem still persists. Should I stick to regularization technique or should I write a user subroutine that will allow more flexibility. 

  Thank you

Kejie Zhao's picture

Fracture of electrodes in lithium-ion batteries caused by fast charging

During charging or discharging of a lithium-ion battery, lithium is extracted from one electrode and inserted into the other.  This extraction-insertion reaction causes the electrodes to deform.  An electrode is often composed of small active particles in a matrix.  If the battery is charged at a rate faster than lithium can homogenize in an active particle by diffusion, the inhomogeneous distribution of lithium results in stresses that may cause the particle to fracture.  The distributions of lithium and stress in a LiCoO2 particle

devendrasingh's picture

shape function for three noded beam element

please any one tell me how i will get the shape function for the three noded beam element

i mean tell me /what is the procedure for the hermite shape function.

how the slopes hermite graphs come ,with releted to the nodal displacement (ζ)which is (-1≤ζ≥1)

 

abaqus and modeling of woven fabric

Hi ppl,

I wud like to know is there any guide to model 2D or 3D woven fabric in abaqus...

plz let me no if u do...

thanks

nilanjan 

 

 

 

What is hydrocode?

Hi! all,

What is the hydrocode? Yet I have know some people use it to simulate the detonation process. Could someone give me some useful information about hydrocode?

   Best wishes!

spring in Abaqus

Hi

I am modelling two plates that have been attached to each other using screws. i have modelled some springs for the screws. the shell element has been used for the plates. i want to assign the spring element (say SPRINGA) for the screws but i do not know how.

thank you.

Can the transformation matrix of a 3-D beam element have any zeros in its diagonal?

Hello,

I am trying to solve the global stiffness matrix for a component assumed to be a series of 3-D beam elements.

Some of the diagonal elements of the transformation matrix are zeros and i eventually end up in finding the inverse of a matrix with some zeros in  its diagonal which is not possible.

Can anyone let me know if the transformation matrix can have zeros along its diagonal?

Thank you.

 

Constitutive Equation

Choose a channel featured in the header of iMechanica: 

Dear friends

Can you help me to find the relationship between true (Cauchy) stress and Almansi strain (constitutive equation)?

thanks

Amit Pandey's picture

Evoution of Yield surfaces: Past and Future Trend - Part 1

It is essential to know the amount of springback for a given forming process, so that the process or the design of the tool can be modified to obtain the desired product shape. This requires a comprehensive understanding of loading and unloading processes, and determination of elastic constants with finite plastic deformation which, in turn, require precise determination of subsequent yield surfaces.

Dynamic Analysis of Shell Element

I have some problems with my matlab code in a 9 node shell
element each node has 5 DOFs. I found that stiffness matrix for each
element is symmetric, but after transformation to global coordinate
system, the transformed stiffness matrices and the resulted global
stiffness matrix of entire shell is nonsymmetric, where order of
transpose([k]) -[k] is approximately E-18.

Mass matrix also has
been antisymmetric after transformation and so I can't solve
characteristic equation to find eigenvalues needed for dynamic analysis.

Henry Tan's picture

Journal Club October 2010: Mechanical behaviour of highly packed particulate composites

Materials such as sedimentary rocks, pharmaceutical tablets, plastic bonded explosives, biscuits, concretes, nacre, solid propellants, seashells and asphalts can be treated as particulate composites that consist of particles of high volume fraction, matrixes of thin layer and interfaces of high specific surface area. Mechanical behaviour of highly packed particulate composites is the theme of this issue of Journal Club forum.

Why penetrable model can be assumed in random?

There is a lot of homogenization theories based on penetrable model or some other name like 'overlapping', 'randomly imbedded model' to analyze random microstructure. In reality, the fibers or inclusions can not be penetrated into each other, so why they use this assumption anyway?

 

 

 Thanks for your opinion.

Constitutive model for the glass fiber reinforced-epoxy composite

Choose a channel featured in the header of iMechanica: 

Dear all,

 

I'm a researcher in the area of applied mechanics. Currently, I'm surveying articles on the constitutive and numerical modeling of fiber reinforced polymer composite. In particular, the fiber is a glass woven fabric. The matrix is the epoxy (thermoset which shrinkages when curing is completed). I want to know woks relevant to this kind of materials. I have found some "compressible hyperelastic model" which is for the epoxy only. Any comments or suggestions will be welcomed!

 

Best regards, 

Sangyul Ha

benzerga's picture

How do ductile materials fail?

This is a review on ductile fracture committed to the Advances in Applied Mechanics (Vol 44). Part of the review has an educational purpose and, as such, is intended for advanced undergraduates and starting graduate students. The other part is an account of recent research conducted in the field.

Prony series for viscoelasticity in Abaqus.

Hi all,

     My first question is i have a set of stress Vs strain data for different strain rates (100/s to 350/s). Can prony series be extracted using these data? Or is there a way in Abaqus i can enter directly this data?

    After reading for a while a came to know that stress relaxation data is needed for defining pony series. My second question is can stress relaxation data can be obtained for high strain rates in the order of 100 to 350/s?

Thanks all 

 

Meshing Complex Volumes in ANSYS

Any ideas on how to mesh a complex volume in ANSYS? I have a 3D model, which is composed of various "added" volumes (meanning, I have only one unit complex volume). Please let me know your opinion in this regard. Thanks.

Publication List

 Book Chapter
   
1.  Peng Xu, Zhonghua Wu and Arun S. Mujumdar, Mathematical Modeling of Industrial Transport Processes, TPR Group, NUS, Singapore, 2009.

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