🧱 Meso/Micro scale modelling
Heterogeneity, lattice methods, fracture–transport coupling.
Grassl Group
Concrete Mechanics for Performance Based Design
Damage–plasticity constitutive models
Support for CDPM / CDPM2
- CDPM2 in OOFEM — actively maintained (main implementation).
- MAT_CDPM (MAT_273) for LS-DYNA — by Peter Grassl & Dimitrios Xenos (less frequent updates).
- CDPM2 in Abaqus — contributed by Seungwook Seok (not verified by Peter Grassl).
We develop computationally efficient damage–plasticity models for cohesive–frictional materials under multiaxial stress states. In tension and low confinement, response is softening (decreasing stress with increasing deformation), with stiffness degradation and inelastic strains localized in cracks or shear bands. At high confinement, concrete exhibits ductile hardening.
Common frameworks include plasticity, damage mechanics, and coupled damage–plasticity. Together with Milan Jirásek, we developed the Concrete Damage–Plastic Model (CDPM), validated against a wide range of tests and implemented in OOFEM. See IJSS 2006 for a detailed formulation (see also the Erratum) and a 3D yield surface illustration.
We later introduced CDPM2 (with D. Xenos, in collaboration with K. Gylltoft, R. Rempling and U. Nyström) to handle cyclic loading with tension–compression transitions and high strain rates. See the core formulation in IJSS 2013. CDPM2 is available in OOFEM and as LS-DYNA MAT_CDPM (MAT_273).
Ongoing work includes rate dependence in CDPM2 and extensions for fibre-reinforced concrete.
Key publications
- D. Xenos, P. Grassl. “Modelling the failure of reinforced concrete with nonlocal and crack band approaches using CDPM2”, Finite Elements in Analysis and Design 117–118, 11–20, 2016. DOI
- P. Grassl, D. Xenos, U. Nyström, R. Rempling, K. Gylltoft. “CDPM2: A damage–plasticity approach…”, IJSS 50(24), 3805–3816, 2013. DOI · Preprint
- P. Grassl, U. Nyström, R. Rempling, K. Gylltoft. “A damage–plasticity model for the dynamic failure of concrete”, IMACSD, Leuven, 2011. Preprint
- P. Grassl. “On a damage–plasticity approach to model concrete failure”, Engineering and Computational Mechanics 162(4), 221–231, 2009. DOI · Preprint
- P. Grassl, M. Jirásek. “Damage–plastic model for concrete failure”, IJSS 43, 7166–7196, 2006. DOI · Erratum
- P. Grassl, M. Jirásek. “Plastic model with non-local damage applied to concrete”, IJNAMG 30, 71–90, 2006. DOI
See Publications or contact me for more information.
🏗️ Structural modelling
Frames/elements under accidental loading; links across scales.
For students: If you are doing an MSc or undergraduate project using CDPM2 in OOFEM or LS-DYNA, please see our Student Projects Instructions, including setup tips, workflow, and examples.