## Abstrakti

Polygonal finite elements have been drawing increasing attention during the last 20 years in computational mechanics due to some of their superior features over the traditional finite elements. They offer, for example, better flexibility in meshing complex geometries and better accuracy in the numerical solution of some problems. However, the main negative aspect of the polygonal finite elements is the more involved numerical integration since the interpolation functions are usually rational functions.

In this paper, we present some results on a research project aiming at the simulation of rock fracture with a mesoscopic model based on polygonal finite elements. As the mineral texture of many rocks is polygonal, the polygonal finite element method is a natural choice. Here, the rock meso-structure is described as a Voronoi diagram where the Voronoi cells are the physical polygonal finite elements. Then, the minerals constituting the rock are represented by random clusters of polygonal ﬁnite elements.

In order to account for rock fracture, the meso-scopic rock material description is equipped with a damage-viscoplasticity model based on the Hoek-Brown criterion. Due to the asymmetry of the tension and compression behavior of rocks, separate scalar damage variables, driven by viscoplastic strain, are employed in tension and compression. The final aim is to study problems with transient impact loadings, e.g. percussive drilling. For this reason, the system equations of motion are solved by explicit time marching.

In the numerical examples, the capabilities of the present rock material description are demonstrated. Namely, uniaxial tension and compression tests of a numerical rock sample are simulated under plane strain conditions. Finally, the dynamic Brazilian disc test simulations are carried out as a dynamic example. These simulations demonstrate that the present method can capture the salient features, including the stress-strain response and the failure modes, of typical rock behavior in these applications.

In this paper, we present some results on a research project aiming at the simulation of rock fracture with a mesoscopic model based on polygonal finite elements. As the mineral texture of many rocks is polygonal, the polygonal finite element method is a natural choice. Here, the rock meso-structure is described as a Voronoi diagram where the Voronoi cells are the physical polygonal finite elements. Then, the minerals constituting the rock are represented by random clusters of polygonal ﬁnite elements.

In order to account for rock fracture, the meso-scopic rock material description is equipped with a damage-viscoplasticity model based on the Hoek-Brown criterion. Due to the asymmetry of the tension and compression behavior of rocks, separate scalar damage variables, driven by viscoplastic strain, are employed in tension and compression. The final aim is to study problems with transient impact loadings, e.g. percussive drilling. For this reason, the system equations of motion are solved by explicit time marching.

In the numerical examples, the capabilities of the present rock material description are demonstrated. Namely, uniaxial tension and compression tests of a numerical rock sample are simulated under plane strain conditions. Finally, the dynamic Brazilian disc test simulations are carried out as a dynamic example. These simulations demonstrate that the present method can capture the salient features, including the stress-strain response and the failure modes, of typical rock behavior in these applications.

Alkuperäiskieli | Englanti |
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Tila | Julkaistu - 2018 |

Tapahtuma | The 44th Israel Symposium on Computational Mechanics - Ben Gurion University, Beer Sheva, Israel Kesto: 22 maalisk. 2018 → … |

### Conference

Conference | The 44th Israel Symposium on Computational Mechanics |
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Lyhennettä | ISCM-44 |

Maa/Alue | Israel |

Kaupunki | Beer Sheva |

Ajanjakso | 22/03/18 → … |