A brief introduction to the MatDEM
The discrete element method can effectively simulate the discontinuity, non-uniformity and large deformation failure of rock and soil. It has extensive application values in scientific researches and applications. Based on the original matrix discrete element computing method, the high-performance discrete element software MatDEM realizes the discrete element numerical analysis at the engineering scale.
Chun Liu,
School of Earth Sciences and Engineering, Nanjing University
E-mail: chunliu@nju.edu.cn
Features of MatDEM
High performance: Based on the original matrix discrete element calculation method, the MatDEM supports the discrete element numerical analysis of engineering scales;
Theoretical innovation: Proposed the macro-micro conversion theory of the discrete element method, improved multi-field and fluid-solid coupling methods, etc.;
Free for the academic community: The software was developed from scratch since 2011, we hold all the copyright, and it is free for the academic community;
Complete functions: It provides complete pre-processing, solver, post-processing and secondary development functions;
Designed for applications: It focus on the analysis of basic problems in the fields of geology and geotechnics;
Open and shared: Rich APIs are provided, with which one may develop a new professional discrete element analysis software (App).
Functions of MatDEM
Pre-processor: Supports reading and writing of multiple types of files, digital elevation, and image modeling, providing rich geometric modeling functions, etc .;
Solver: Supports both CPU and GPU computing, and high-performance computing of 3 million three-dimensional elements on a single GPU;
Post-processor: It provide drawing of dozen types of graphics, and the results can be saved as image and vector files, GIF animation and video, etc.;
Extension module: Easy to add new properties, pre- and post-processing types, functions and window applications to the software; supports new contact models;
Secondary development: Provide dozens of cases and App source code, including test simulation, geological disasters, geotechnical engineering, dynamic effects, planetary motion, multi-field coupling, fluid-solid coupling and other categories;
Real-time control: You can stop the calculation at any time, view all calculation parameters, and then continue the calculation.
Teaching promotion of MatDEM
Textbook: The Chinese book of the MatDEM "Matrix Discrete Element Analysis of Geology and Geotechnical Engineering" was published by Science Press in June 2019, and the English book will be published by Springer Press at the end of 2020;
Online Course: Online teaching video is provided (with English subtitles), which introduce the principle of discrete element and the application of the MatDEM software;
Technical training: With the support of the Chinese Society of Rock Mechanics and Engineering, the "Discrete Element Method and MatDEM Technical Training" is held during the annual China Rock conference;
Online resources: The software and the source code of cases can be downloaded from the MatDEM website http://matdem.com (in Chinese and English)
Communication platform: MatDEM WeChat public account "矩阵离散元MatDEM", communication QQ group number: 668903775;
Scholarships: The "MatDEM Scholarships" was founded to reward students who apply the MatDEM in their researches and engineering practices.
Cases of the MatDEM (source code is provided in the software)
Figure 1 Cases of high-performance discrete element software MatDEM (software, source code and tutorial download http://matdem.com)
1. Conversional triaxial test; 2. Three-dimensional landslide 1; 3. Meteorite impacts the ground; 4. Soft and hard interlayer modeling; 5. Automatic training materials; 6. Three-dimensional landslide 2; 7. Pile-soil interaction; 8. Sand slide 9. Rolling stone impact screen; 10. Structural sandbox simulation; 11. Shield hob rock breaking; 12. Tunnel and rock burst; 13. Model combination and cutting; 14. Microwave assisted rock breaking; 15. Tunnel and ground Settlement; 16. Direct shear test; 17. True triaxial test; 18. Seismic dynamic action; 19. Ground subsidence and ground fissure; 20. Blasting action; 21. Soil loss and cracking; 22. Thermal-mechanical coupling of energy piles; 23 .Micro image modeling; 24. Image cutting model; 25. Hydrothermal coupling; 26. Hydraulic fracturing; 27. Monte Carlo analysis of slope; 28. Drum stirring; 29. Custom function modeling; 30. Permeation test 31. Grouting process; 32. Excavation process.
Window interface of the MatDEM (supports six languages)
Figure 2 Startup window of MatDEM version 1.78
Figure 3 Secondary development interface of MatDEM
Figure 4 Post-processing interface of MatDEM
Apps of the MatDEM
Figure 5 Using App Designer to design the interface of the application
Figure 6 Application editor of MatDEM
Figure 7 MatDEM application example-geometric modeling
Figure 8 MatDEM application example-drum stirring
Figure 9 MatDEM application example-3D landslide simulation system
Figure 10 Principle paper and help file of MatDEM
Understanding the discrete element method
In the discrete element method, a series of particles with specific mechanical properties are stacked and cemented to build a rock and soil model. In the most basic linear elastic model, it is assumed that the particles are in contact with each other and interact with each other via a spring force. Based on classic Newtonian mechanics, the particle acceleration, velocity, and displacement are calculated through a time-step iterative algorithm. Then the simulations of the deformation and failure process of macro rocks and soils are realized.
Figure 11 Basic principles of the discrete element method