# ABAQUS

## 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 ?

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).

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?

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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.

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)

## Is it possible to solve buckling in Abaqus with only residual stress defined as predefined load?

Hi Sirs,

As title, I wondering if the problem can be solved with only material residual stress but no other external load applied?

After several trials, Abaqus returns message
"MASS OR DIFFERENTIAL STIFFNESS MATRIX IS COMPLETELY NULL. THE EIGENPROBLEM CANNOT BE SOLVED. IN A *BUCKLE ANALYSIS THE MOST LIKELY CAUSE IS THAT A NONZERO LOADING PATTERN WAS NOT SPECIFIED VIA *BOUNDARY, *CLOAD, *DLOAD, ETC,. SEE Eigenvalue Buckling Prediction IN THE ABAQUS/STANDARD USERS MANUAL"

## UMAT for MAZAR's Concrete Damage Model

Hello All,

I am working on stochastic upscalling of damage in concrete microstructure. Can someone provide a UMAT for Mazar's damage model or any resource to help me create UMAT on my own.

Thank you.

Vasav Dubey

Texas A&M University

Texas, USA

## UMAT for Zener model and Kelvin-Voigt model

Dear iMechanica community,

you can find the UMAT-implementation of a Zener model, i.e. a Maxwell model parallel to a spring, in my PhD thesis:

“Upsetting and Viscoelasticity of Vitreous SiO2: Experiments, Interpretation and Simulation“
Technische Universitaet Berlin, Germany, 2006
https://depositonce.tu-berlin.de/handle/11303/1574
http://dx.doi.org/10.14279/depositonce-1277

## Applying a moving pressure and traction in Abaqus

Hello all,

I have applied a moving ellyptical hertzian pressure load on a surface using a DLOAD which works, but I also need the traction load which is the multiplication of this pressure with a friction coeffcient.

Does anybody have any clue how to do it? Directly through abaqus or inside the same DLOAD?

Kind regards,

Omid

## How do I rectify an error regarding memory storage when I generate substructures in ABAQUS?

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I have been trying to generate a substructure in ABAQUS for a big diameter roller bearing. I have used two reference points, one each for inner and outer raceways to couple the inner and outer raceway surfaces. I have two steps in the analysis. The first step is Frequency followed by Substructure generation step. The analysis runs fine till the end of first step and calculates the eigen frequencies. When the second step starts, following error message appears.

" Element 439473 requires more than 2GB of memory for storage"

## Pressure Difference Calculation in ABAQUS

Hi everyone,

I am working on ABAQUS to simulate Pipeline Inspection Gauge (PIG) movement in a pipeline via CEL technique. I am unable to find how to calculate Pressure Difference in the pipeline using Abaqus.

If anyone of you can guide me through it.

Regards,

MD Aftab

## Modeling with line spring elements to find failure pressure of steam generator tube

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Hello, All
I am trying to model steam generator tube of length 110 , radius 11mm, thickness 1.27mm. It has 2 axial cracks of length 6.35mm. length between 2 cracks is 0.254mm.

## Simplified slip-bearing action by using stop ellement in Abaqus

Hi
can anyone please advise me to define connector ellements with following details:
Using rigid plastic CARTESIAN element and a STOP element in parallel and The connector behaviour must be:
1- rigid up to the slip force limit Rn
2- slip at the bolts up to ±1 mm at constant force Rn
3- rigid bearing hardening

## ABAQUS, partitioning an edge

Hello Everyone,

Does anyone knows how it is possible to partition an edge in one step with multiple points (like multiple datum points or multiple parameter values)? I know how to partition one edge one by one. The problem of doing it one by one is the amount of time that it takes to do that. For example if I want to put 50 points on one edge I have to pick that edge 50 times and partition it, which takes a lot of time.

I am doing the whole process by scripting with Python so I would be glad if the solutions are in scripting format (I am using ABAQUS 2016).

## How to obtain the Force-Indentation depth curve of nanoindentation FEA?

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Dear all experts,

I did FEA of nanoindentation with using Abaqus and considered displacement of reference point (RP) on the indenter as a punching tool. Moreover, Abaqus/Explicit method  was applied for solving problems.

But I do not know how to plot Force-Indention depth curve via FEA with using Abaqus.

Any suggestions would be greatly appreciated.

Amin

Hello everyone,

## UMAT Non linear Viscoelasticity - Algorithm verification?

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Hello everybody,

My task is to write a UMAT for Non-linear Viscoelasicity based on Schapery's model in ABAQUS. I have coded the routine, but I am still not able to predict correct response. I tried to debug it as much as I can. I understand that it would be difficult for anybody to understand my code. So, I have attached a flowchart (pdf) of the whole algorithm that I follow. It would be nice if you could check that and correct me if I am wrong.

Regards

Shree