Accompanying data and videos for paper "A time-discontinuous elasto-plasticity formalism to simulate instantaneous plastic flow bursts"

In the archive

This archive includes simulation data associated with the research detailed in the article, as well as videos illustrating the simulations.

Paper link:

International Journal of Solids and Structures: https://doi.org/10.1016/j.ijsolstr.2024.113171

arXiv: https://doi.org/10.48550/arXiv.2412.02475

Paper Description

Plastic flow is conventionally treated as continuous in finite element (FE) codes, whether in isotropic, anisotropic plasticity, or crystal plasticity. This approach, derived from continuum mechanics, contradicts the intermittent nature of plasticity at the elementary scale. Understanding crystal plasticity at micro-scale opens the door to new engineering applications, such as microscale machining. In this work, a new approach is proposed to account for the intermittence of plastic deformation while remaining within the framework of continuum mechanics. We introduce a material parameter, the plastic deformation threshold, corresponding to the plastic deformation carried by the minimal plastic deformation burst within the material. The incremental model is based on the traditional predictor–corrector algorithm to calculate the elastoplastic behavior of a material subjected to any external loading. The model is presented within the framework of small deformations for von Mises plasticity. To highlight the main features of the approach, the plastic strain increment is calculated using normality rule and consistency conditions, and is accepted only if it exceeds the plastic threshold. To achieve this, a time-discontinuous generalization of the Karush-Kuhn–Tucker (KKT) conditions is proposed. The simulations show that the introduction of the plastic threshold allows for the reproduction of the spatiotemporal intermittence of plastic flow, capturing the self-organization of plastic flow in complex loading scenarios within an FE model.

Funding sources

This work was funded by the French ANR (Agence Nationale de la Recherche) under the MESOCRYSP project (ANR-21-CE08-0030).

Data structure and information

Overview

This archive contains simulation data related to the research presented in the article *"A time-discontinuous elasto-plasticity formalism to simulate instantaneous plastic flow bursts"*. The data is organized by the varying parameters used in the simulations and includes two main types of files:

1. **`fichierXDMF_DATA.dat`**: Contains averaged values of various quantities (e.g., stress, strain) over the gauge length.2. **`fichierProfile_dpcum.dat`**: Contains the profile of plastic strain increment over the Ox axis, or in some cases, cumulative plastic strain. For cumulative plastic strain, a post-treatment is necessary to obtain the plastic strain increment.

File Types

1. `fichierXDMF_DATA.dat`- **Description**: This file includes the averaged values for a range of physical quantities such as stress, strain, etc., over the gauge length.- **Data Format**:   - Each column represents a different quantity, and the rows correspond to the values recorded at each numerical step of the simulation.

2. `fichierProfile_dpcum.dat`- **Description**: This file provides the profile of the plastic strain increment along the Ox axis for each numerical step. In some cases, this file will contain the cumulative plastic strain, which will require a post-processing step to compute the plastic strain increment.- **Data Format**:  - The data is organized with respect to the spatial position along the Ox axis, with each row corresponding to a different spatial point and the value representing the strain or strain increment.

Data Organization

- The files are organized based on which parameter was modified during the simulation. Each folder corresponds to a different parameter set, and contains the relevant `.dat` files for that set of conditions.- Simulation results are reported for every numerical step.

Usage

Post-Processing- For files containing **cumulative plastic strain**, you will need to perform post-processing to calculate the plastic strain increment:    \[  \Delta \epsilon^p = \epsilon^p(n) - \epsilon^p(n-1)  \]    where \( \epsilon^p(n) \) is the cumulative plastic strain at step \( n \) and \( \Delta \epsilon^p \) is the plastic strain increment between steps.

Code 

Simulation code with examples can be found at: https://github.com/Mathias-Lamari/Time-discontinuous-plasticity

Contact

For further information on this dataset, please contact [e-mail]