Grassl Group
Concrete Mechanics for Performance Based Design

MAT_CDPM (MAT_273) in LS‑DYNA

This page provides information about the implementation of CDPM2 in LS‑DYNA (material model MAT_CDPM, also referenced as MAT_273). Information is provided “as is”. If you spot issues or can share improvements, please contact Peter Grassl. Most examples were run with the double‑precision builds of LS‑DYNA Release 9.3.1 or later.

Outline

• Background
• User material subroutine
• Key references

Background

The model builds on Grassl & Jirásek (2006), Grassl et al. (2011), and Grassl et al. (2013). The original CDPM couples an effective‑stress plasticity model (pressure‑sensitive hardening) with a scalar damage variable (stiffness degradation and softening), using perfect plasticity in the post‑peak while softening is handled by damage.

CDPM2 extends this framework (with K. Gylltoft, R. Rempling, U. Nyström) by:

• introducing post‑peak hardening in the plasticity part (sharing softening between plasticity and damage),
• using two damage variables (tension / compression) to better handle tension–compression transitions,
• adding strain‑rate dependence in the damage onset (see the 2011 conference paper).

CDPM2 first appeared in LS‑DYNA around 2013–2014 as MAT_CDPM (MAT_273). In 2015, Dimitrios Xenos and Peter Grassl re‑implemented the model for improved robustness; this version ships from Release 9.1 onward.

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User material subroutine

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Key references

• P. Grassl, D. Xenos, U. Nyström, R. Rempling, K. Gylltoft (2013). “CDPM2: A damage–plasticity approach to modelling the failure of concrete.” International Journal of Solids and Structures 50(24), 3805–3816. DOI · Preprint
• P. Grassl, U. Nyström, R. Rempling, K. Gylltoft (2011). “A damage–plasticity model for the dynamic failure of concrete.” 8th Int. Conf. on Structural Dynamics, Leuven. Preprint
• P. Grassl, M. Jirásek (2006). “Damage–plastic model for concrete failure.” IJSS 43, 7166–7196. DOI · Erratum

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