Brittle Crack Mode 2 ... possible in OGS?


For my studies I am looking for a software to simulate the fracture deformation of a triaxially loaded rock. In the attachment you can see a short sketch of the experimental procedure. In a first step, an all-sided load is applied to the specimen. Then the vertical force is increased, a crack is formed, which eventually leads to the failure of the specimen.

I have not found any more detailed information on the subject on the homepage. Only the benchmark “Linear, single fracture” represents a crack opening (mode 1). However, what I want to represent is a shear deformation (mode 2) of a brittle material.

Is OGS able to simulate such behavior?

I am only aware of FEniCS regarding brittle fracture modelling

Where it matters in your modelling, you could couple FEniCS (python bindings) with OGS (native cpp bindings) using PreCICE:

Hi @froido ,

My expertise is definitely not on fracture mechanics but my colleague @keita.yoshioka maybe can tell you much better

Best wishes

HI @froido,

Mode-II (or any mixed mode) brittle fracturing is possible through a phase-field approach in OGS, but our current implementation does not account for frictional fracture as described in the attachment.

Best Regards,

Thanks for these information!

@timc0up : FEniCS seems to be an interesting tool for fracture modeling. I will dig a little deeper into this tool.
@keita.yoshioka : I have already thought about a phase-field approach, but I couln’t find any information on the OGS website. Maybe the frictional fracture will be feature in a future release. :wink:

Wencheng Jin’s PhD dissertation might be useful to you:

Computational Modeling of the Transition from Damage to Fracture in Intrinsically Anisotropic Porous Media

The initiation and propagation of discontinuities in brittle materials is of great interest to engineers, at several scales. Discontinuities can be detrimental for structures (borehole for nuclear waste disposal, cavity for storage, tunnel for transportation) but discontinuities are necessary to extract energy (hydraulic fracturing for oil, gas and geothermal resources). A number of numerical tools are available to model fracture propagation in brittle solids. However, the fundamental inception mechanisms at the micro-scale are not fully understood. Therefore, the goal of this doctoral research work is to understand the processes that govern the initiation and propagation of micro-cracks in mixed mode in crystalline and porous media, and to predict the transition from diffused micro-crack distribution to discrete macro-fracture.

Thank you for your comments. Phase-field brittle fracture is being merged with the master branch. Probably in the next release, it will be there.
As for frictional fracture, indeed we are currently working on it. As it is still quite a new research topic with only 2 groups that have published their implementations so far (Hongkong U and Columbia U), it will take us a bit more time, but please watch this space…

Best Regards,