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ABAQUS UMAT CPFEM Subroutine

Dear All, 

We are working on Equal Channel Angular Pressing (ECAP) project and we are trying to implement CPFEM with Abaqus UMAT, there are few examples online but we could not able to run them on abaqus 6.13 with any subroutine. Does anyone have any working subroutines on related subject?

Kind Regards

 

Yunus Emre Kulhan

ABAQUS: Access stress of integration point of elements during calculation

Hi all,

I'm using ABAQUS and UMAT for structural simulation. I used quadratic element (CPS4) with 4 integration points (IP).

During the calculation (which calling my UMAT), at each time step, for each element, I need to calculate the average stress of these IPs and produce a state variable for these IPs from this average stress. Then, I would need to update this state variable back to these IPs in that element. But as far as I know, the ABAQUS call UMAT for every IP and calculate everything within this current IP.

Emilio Martínez Pañeda's picture

Abaqus2Matlab: A suitable tool for finite element post-processing

A new piece of software has been presented that connects the well-known FE code Abaqus with Matlab. The source code, detailed documentation and a large number of tutorials can be freely downloaded from www.abaqus2matlab.com 

Some interesting applications are addressed in the associated journal article:

http://www.sciencedirect.com/science/article/pii/S0965997816306512 (a pre-print is available at www.empaneda.com)

Comparing performance of user subroutines in Abaqus

Dear Mechanics community,

My current research work is focused on simulation of NiTi stents.

I need to benchmark my UMAT subroutine against inbuilt VUMAT subroutine for SMA in Abaqus.

It would be great to have suggestions on how can I go ahead on this task (like typical benchmark analysis, simulation of CAD models etc.,).

The basic idea is to analyse the limits of both the subroutines.

Warm Regards,

CompMech enthusiast...

Calculating material jacobian matrix for ABAQUS UMAT subroutine

Hello everyone, 

 

I found that there is no comprehensive topic about how to calculate material jacobian matrix for UMAT while it's one of the most complicated and important parts of writing a subroutine and a lot of the researchers deal with it. 

I think it would be great if experts share their sources and experiences here for all. I personally, try to provide the basics and essential materials as well. 

Here is an essential available PDF on Imechanica:

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rajan_prithivi's picture

creating a perfect spherical hole in an orphan mesh (Abaqus)

Hello All,

I have an 3D orphan mesh (Abaqus)  that I obtained from the Gmsh software. I would like to insert a perfect spherical hole in that mesh.

 

I selected all the elements inside a sphere and deleted them but i am getting a very coarse surface, look at the figure attached

Is there a way to create a perfect spherical hole in a 3D Abaqus mesh ( I do not have the part geometry)  ?

 

I thought something like,  smooth the inside of the surface of the mesh deletion, but I donot know how to do that.

 

Properties of cohesive surface on cohesive elements

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Hello everyone,

I have a simple ABAQUS model with cohesive surface and I want to create a comparable model with cohesive elements instead of the surface. Applying the same properties onto the cohesive elements does not give me the desired results. Then I read somewhere that the properties cannot be applied on the elements directly the same way.

So how do I apply my interface properties onto the material of the cohesive elements? I thought that I should consider the thickness of the elements, but still until now I have not succeeded yet...

Thank you in advance.

Which theory Abaqus' Contour Integral for the determination of SIFs is based on?

I am actually using Abaqus' Contour Integral for the determination of stress intensity factors. But I do not know, which theory it is based on. Is it the same like the path-independent determination of J integral? Or is there a difference?

Modeling and Simulation Engineer Position at Schlumberger India Engineering Center

We, Schlumberger India Technology Center Pvt. Ltd (Located at Pune, India), looking for fresh graduates for our Modeling and Simulation Group. The candidate should be completed or on the completion of his/her Ph. D. in the area of Applied Mechanics (Structural/Fluid) with a strong academic background. As a mechanical modelling and simulation engineer, he/she will execute and lead analytical simulation effort, with the FEA/CFD modelling techniques, for complex mechanical parts/assemblies and complex physics. The details of the job description will be communicated later. If you are interested kindly send your resume on agaonkar@slb.com

Prabuddha Sathurusinghe's picture

Different results when *DEFORMATION PLASTICITY vs *PLASTIC used for modelling plasticity of ductile meals in ABAQUS?

I got different results for a tensile test simulation when I used *DEFORMATION PLASTICITY (DP), instead of *PLASTIC (P) to model the same material. Ramberg-Osgood (R-O) parameters were directly provided for DP model while true stress/plastic strain values were calculated using the same R-O parameters for P model. Could somebody provide some insight into why that happened? This is not a fracture problem.

Alternative to Cohesive Elements / Surface

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Hello,

I want to analyze the interface between the fiber and the matrix in a fiber reinforced composite and I am now looking for the right material model.

In Abaqus there are the options of using cohesive elements or cohesive surface. As an alternative I want to model the interface as a third layer with solid elements.

My idea is to use the existing model Concrete Damaged Plasticity. Does this make sense?

Thank you in advance.

sbagherzadeh's picture

Seeking a PostDoc position in field of mechanics of advanced materials

Dear All,

I got my PhD degree of Mechanical Engineering on Sep 2016 and I am seeking PostDoc position at well-known Universitiy or research Institute. Also, I completed my short-term visiting scholar at Purdue University on March 2016.

kshitij_gaikar's picture

Unconnected regions in abaqus

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I am new to abaqus and currently working in Abaqus 2016

I am getting the error 5 unconnected regions in abaqus. I have checked thoroughly all the interefaces and boundary conditions but I am not able to sort out this problem. Also I am getting Displacment increment is too big for contact. The job is getting aborted eventually.

I have attached images of the model.

Borad M Barkachary's picture

Is there any way to assign element based surface for 2D shell element??

I am trying to simulate 2D metal cutting simulation using surface to surface contact in dynamic explicit model. But what I am seeing is.. there is no contact between workpiece surface with failed element (i.e. Chips) which reduces the force value during simulation.

In 3D simulation for 3D stress element (C3D8R), I can do element based surface by editing the input file. Is there any such way in 2D shell element (say CPE4R) also? Please help

Twebb83's picture

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Marwan Shehata's picture

Asking for help in BAJA SAE Car

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Hello,I've joined a racing contest for Off-Road cars , called Baja SAE ( Society of Automotive Engineers)

The car contains tubes that are welded together or attached together by flanges

I am familiar with Abaqus and ANSYS btw

What are the main aspects that we should consider in modeling and simulating a baja sae car ?
BAJA SAE Car to be made

Can you help me with this?

Plasticity model in Abaqus to capture the continues plastic strain of granular material under triaxial cyclic loading?

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I am working on modelling ballast aggregates under triaxial loading. Confining pressure applied in the intermediate and minor principal direction and cyclic compression load applied in the major principal axis direction. I wanted to capture the continues plastic strain (PS) with cycles (N). My test results show that the PS increase with N up to about 10,000 cycles and the rate of strain slowly diminish for later cycles and almost stay constant after N=100,000. What available model in Abaqus can be used to get this behaviour. I have to run my analysis at least for 10,000 cycles.

ABAQUS - Stress Intensity Factor for Single Radial Crack in Thick Walled Cylinder

Hi,

I am trying to analyze the stress intensity factor (SIF) using contour integral of a 2D thick walled cylinder under plane stress with different wall ratios under internal pressure loading only and a single radial crack of varying length in Abaqus.

The wall ratio (inner & outer radius) I am interested in modelling is of ratio 6 (i.e. for inner radius of 1, outer radius is 6).

I have modelled ratios from 1-6 with crack length varying from 0.1-0.9 of the wall thickness. (i.e. for ratio 3, the wall thickness is 2, hence the crack varies from 0.1-0.9 x 2).

Abaqus VDLOAD/DLOAD

I'm using the ABAQUS DLOAD subroutines, and I'm curious what the dimensions of the 

volume distributed body load should be. 

 

I understand ABAQUS uses [LT-2] for GRAV body loads. However, I'm curious if the 

units for BZNU acting over a volume should be [density]*[acceleration] or just

[acceleration].

 

Thank you,

Anirban

crack propagation in Abaqus (VCCT) with remeshing

I started using VCCT with quarter tip elements in Abaqus (not XFEM). I can solve the problem and get the SIFs.
How can I let the crack grow? Has someone a script for crack growth and remeshing that I can implement?

ABAQUS, DLOAD, new active load surface, element deletion

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Dear all,

Currently I am engaged in solving a geological problem. So we have some soil model in the form of disk, there is a circular hole in the center, which has the initial pressure at the reference time  (a modelling of the soil injection with the polymer compound)

How can I recalculate the normal pressure inside the circular hole of the soil model using the DLOAD subroutine if the neighbouring FEs were failed.

DLOAD, element deletion, new active load surface

Dear all,

Currently I am engaged in solving a geological problem. So we have some soil model in the form of disk, there is a circular hole in the center, which has the initial pressure at the reference time  (a modelling of the soil injection with the polymer compound)

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