Concrete Microplane Model - FEA using ANSYS - Lesson 10

This tutorial shows how to use the Microplane model to simulate a concrete cube and reinforced concrete beam. This implementation incorporates coupled plasticity-damage and nonlocal behavior. This is the first tutorial in this series incorporating Mechanical APDL commands into the analysis.

Learning objectives:
1. Sketch the Drucker-Prager yield surface and locate key points and features.
2. Explain the various parameters for the Microplane model and their typical values.
3. Add APDL commands to model complex material behavior and change element types.

=== Downloads ===
Drucker-Prager Yield Surface (Excel):
https://docs.google.com/spreadsheets/d/19H-HMY3dhsJIyrzjqSg7fzgGihHGja_s/edit?usp=sharing&ouid=116718473101577906015&rtpof=true&sd=true
(Link does not have edit access, but you may download a copy of the Excel file to edit it locally)

Microplane APDL Commands for psi (text file):
https://drive.google.com/file/d/1PToSbzrCqu3WDLy1VZcAzSTvuBbf3rg1/view?usp=sharing

Microplane APDL Commands for MPa (text file):
https://drive.google.com/file/d/1XC4uspetbG45U57VfNnYk8W22HMI08_W/view?usp=sharing

=== References ===
This particular implementation in ANSYS is based on the following references:
Zreid, I. & Kaliske, M. (2018). A gradient enhanced plasticity-damage microplane model for concrete. Computational Mechanics. 10(1007), s00466-018-1561-1. https://doi.org/10.1007/s00466-018-1561-1
Zreid, I. & Kaliske, M. (2016). An implicit gradient formulation for microplane Drucker-Prager plasticity. International Journal of Plasticity. 83, 252-272. https://doi.org/10.1016/j.ijplas.2016.04.013
Zreid, I. & Kaliske, M. (2014). Regularization of microplane damage models using an implicit gradient enhancement. International Journal of Solids and Structures. 51(19), 3480-3489. https://doi.org/10.1016/j.ijsolstr.2014.06.020

The original microplane model was developed by Z.P. Bazant and others:
Bažant, Z. P., & Gambarova, P. G. (1984). Crack shear in concrete: Crack band microplane model. Journal of structural engineering, 110(9), 2015-2035. https://doi.org/10.1061/(ASCE)0733-9445(1984)110:9(2015)
Bazant, Z. P. & Oh, B. H. (1985). Microplane model for progressive fracture of concrete and rock. Journal for Engineering Mechanics. 111, 559-582. https://doi.org/10.1061/(ASCE)0733-9399(1985)111:4(559)
Carol I, Jirásek M, & Bažant Z (2001). A thermodynamically consistent approach to microplane theory. Part I. Free energy and consistent microplane stresses. International Journal of Solids and Structures. 38:2921–2931. https://doi.org/10.1016/S0020-7683(00)00212-2