Hello Mauro,

for modelling fatigue, you need to apply load cycles in some way. The only direct method for that which is offered by Abaqus is the direct-cyclic approach. However, I'm uncertain whether it is possible to apply a fatigue criterion for XFEM. I'm only aware of the VCCT-based debond method, which should also work in DC step.

Using a static or dynamic step doesn't give you the possiblity to apply load cycles, unless you model it directly through an amplitude. However, this approach is cumbersome and would surely require a user subroutine to capture the effects of the cyclic loading. Still if you do that, I would rather calculate the load cycles from the step time and not actually alternate the load amplitude.

Cheers,

Raffael

Hi Raffael,

Thank you for your response. The problem that I am currently facing is that when I want to create an interaction in Abaqus with a direct-cyclic step the XFEM crack-growth option is not available. It is available if I consider a step with a static, general procedure. I am using Abaqus 2019.

Is there a way to model crack growth using XFEM for HCF in Abaqus?

Kind regards,

Mauro Francisco Arcidiacono

Hello Mauro Francisco Arcidiacono

What type of material do you model?

1. Ductile materials with stresses reaching inelastic deformations

• direct cyclic analysis is preferred
• The load cycling and reversals of inelastic stresses cause plastic strains accumulation or a stabilized response (Fourier series and time integration of the nonlinear material behaviour are needed)
• Progressive damage and failure are directly simulated, based on the continuum damage mechanics

2. Brittle materials or materials with small-scale yielding

The fatigue crack growth analysis needs a user-defined subroutine for compiling an appropriate crack growth law (eg Paris Law) with the XFEM capabilities in ABAQUS to calculate the 3D HCF crack growth and propagation

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If you read the Abaqus documentation (links below), about the analysis types you can select the best one for your problem. Reading the overview at the top of the documents may be enough:

- Static Stress

http://130.149.89.49:2080/v2016/books/usb/default.htm?startat=pt03ch06s02at01.html

- Implicit dynamic

http://130.149.89.49:2080/v2016/books/usb/default.htm?startat=pt03ch06s03at07.html

- Low-cycle fatigue analysis using the direct cyclic approach http://130.149.89.49:2080/v2016/books/usb/default.htm?startat=pt03ch06s02at06.html

Hello Lamprini Papargyri

I want to do crack growth analysis by X-FEM ABAQUS under cyclic loading. The applied stress level is in the high cycle range. I know about STEP available for fatigue in ABAQUS (Direct cyclic), but this step is only used for low cycle fatigue.

you mentioned above that for brittle materials needs a user-defined subroutine

Can you help me which subroutines should be used for this simulation?