Authors: | Langenfeld, K. Kurzeja, P. Mosler, J. |
Title: | How regularization concepts interfere with (quasi-)brittle damage: a comparison based on a unified variational framework |
Language (ISO): | en |
Abstract: | Three regularization concepts are assessed regarding their variational structure and interference with the predicted physics of (quasi-)brittle damage: the fracture energy concept, viscous regularization and micromorphic regularization. They are first introduced in a unified variational framework, depicting how they distinctively evolve from incremental energy minimization. The analysis of a certain time interval of a one-dimensional example is used to show how viscous and micromorphic regularization retains well-posedness within the softening regime. By way of contrast, the fracture energy concept is characterized by ill-posedness—as known from previous non-variational analyses. Numerical examples finally demonstrate the limitations and capabilities of each concept. The ill-posed local fracture energy concept leads by its design to a spatially constant fracture energy—in line with Griffith’s theory. The viscous regularization, in turn, yields a well-posed problem but artificial viscosity can add a bias to unloading and fracture thickness. Furthermore, and even more important, a viscous regularization does not predict a spatially constant fracture energy due to locally heterogeneous loading rates. The well-posed micromorphic regularization is in line with the underlying physics and does not show this undesired dependency. However, it requires the largest numerical efforts, since it is based on a coupled two-field formulation. |
Subject Headings: | Variational framework Damage mechanics Fracture energy concept Viscous regularization Micromorphic regularization |
Subject Headings (RSWK): | Schadensmechanik Numerisches Modell Spröder Werkstoff |
URI: | http://hdl.handle.net/2003/41837 http://dx.doi.org/10.17877/DE290R-23680 |
Issue Date: | 2022-09-05 |
Rights link: | https://creativecommons.org/licenses/by/4.0/ |
Appears in Collections: | Institut für Mechanik |
Files in This Item:
File | Description | Size | Format | |
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s00161-022-01143-2.pdf | DNB | 2.04 MB | Adobe PDF | View/Open |
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