Are you aware that Abaqus has a totally independent module known as FE-Safe for the fatigue design.

The section your referring to is about low cycle fatigue which means that loads are so high that the system breaks in less than 1000 cycle. This is common under earthquake loading where joints may fail in less than 20 cycles. You don't need Python script. You can do everything in CAE.

If you explain the problem better you will get  better answer and hopefully relevant to your problem. 

Are you aware that Abaqus has a totally independent module known as FE-Safe for the fatigue design.

The section your referring to is about low cycle fatigue which means that loads are so high that the system breaks in less than 1000 cycle. This is common under earthquake loading where joints may fail in less than 20 cycles. You don't need Python script. You can do everything in CAE.

If you explain the problem better you will get  better answer and hopefully relevant to your problem. 

thanks.

im trying  to analys fatigue with python script in fact its such training.iam aware that i can analys low cycle fatigue  with Abaqus GUI, even i think we can do this with UMAT subroutin. but im focusing my attention to write python script for fatigue.

Dr Sirous and Maryam can you please tell me how to obtain crack initiation life using CAE 

in direct cyclic analysis getting warning as Field o/p  CYCLEINI is not available for selected element type .

we can analyze low cycle fatigue life directly in caE but for analysing haigh cycle fatgue because of changing property of metal we must write python script or UMAT subroutin, i have problem in second part

Thank you.

I am getting error in LCF analysis can you help me out?

and about pythan  scripting I did very small work but I have Gautam Puris guide book for pythan scripting It may help you

Maryam kindly check your inbox .

Did u get the file?

Hi Vipin,

CAE is a CAD based modeler.  You can use Abaqus as a solver for the crack initiation (and propagation).  There are a few models in Abqus such as X-FEM and damage plasticity which you can use.

You can find some info  on a previous thread on crack initiation on Rrsearchagte.

https://www.researchgate.net/post/Is_there_any_method_that_can_simulate_crack_initiation_and_crack_growth_in_ductile_metals_under_fatigue_loading_without_defining_pre-crack_in_ABAQUS

The following  gives a simple example  using X-FEM in abaqus for crack imitation

http://www.matthewpais.com/2d-crack-initiation

More references.

http://www.3ds.com/fileadmin/PRODUCTS-SERVICES/SIMULIA/RESOURCES/Def-XFEM-Analyses-of-Critical-Cracks-in-a-Pressure-Tap.pdf

http://repozitorij.fsb.hr/3611/1/Fatigue%20crack%20initiation%20and%20propagation%20modelling%20using%20a%20cyclic.PDF

http://eprints.qut.edu.au/65236/1/Predicting-Crack-Initiation-Due-to-Ratchetting-in-Rail-Heads-Using-Critical-Element-Analysis.pdf

 Note that the above approach are on macro scale.  The current research revolves around multi-scale approach where crack initiation is studied at the atomic level.  See for example

http://www.sciencedirect.com/science/article/pii/S0022509615303379

http://www.springer.com/us/book/9781402085192

https://www.academia.edu/26323794/Multiscale_modeling_approach_to_stress_corrosion_cracking?auto=download

Hi Vipin,

Do you analyzing with abaqus ?

i think for LCF you can analyze with direct Cycle Step. Be aware a bout Editing keyWord .Whats exactly your problem ?

Problem is in direct cyclic step having o/p parameter as CYCLEINi which gives no. Of cycles to initiate damage 

but for each run I am getting warning as CYCLEINi is not available for your selected element type ..

I am facing the same problem as Vipin. Could anyone tell What is the solution of that? Not only cycleini, but also outputs like 'sdeg' 'damaget' etc is showing the same response. If it is like that, how can we possibly take out the output for a low cycle fatigue problem?

Considering a low cycle fatige (

From my research what I found out was, we should give the damage criterion as 'Hysteresis energy'. and we have to input this only by editing the input file.

DAMAGE CRITERION=HYSTERESIS ENERGY

followed by the parameter values

I think it will be of more use if you are doing 'strain controlled low cyce fatigue'

(Abaqus/CAE doesn't support the input of hysteresis energy required for fatigue failure, Abaqus/Standard does). If we didn't specify this criterion the warning during the job submission monitoring will always show- output cycleini cannot be generated for this element type.

I think that at low cycle fatigue (typically

FE-Safe using non-linear FEA and Strain Life Prediction is the best approach for Low Cycle Fatigue. No need for Python.

https://re-test.com/fatigue-analysis-consulting