Two material models are considered here in the load limit analysis of concrete:
Drucker-Prager concrete material model (see also Drucker-Prager Concrete in the Material Reference)
Menetrey-William concrete material model (see also Menetrey-Willam in the Material Reference)
The properties listed in the table below have been defined in the tab of Workbench in two separate analysis systems, and their results are compared (see Results and Discussion). Both models use exponential softening. The reinforcement material uses Bilinear Kinematic Hardening model.
| Material Properties for Concrete Material Models | ||
|---|---|---|
| DP[a] | MW[b] | |
| Young's Modulus (GPa) | 30 | 30 |
| Poisson's Ratio | 0.2 | 0.2 |
| Density (Kgm-3) | 2500 | 2500 |
| Uniaxial compressive strength (MPa) | 28 | 28 |
| Biaxial compressive strength (MPa) | 33.6 | 33.6 |
| Uniaxial tensile strength (MPa) | 2.2 | 2.2 |
| Dilatancy factor in tension | 0.25 | -- |
| Dilatancy factor in compression | 1 | -- |
| Dilatancy angle (°) | -- | 20 |
| Plastic strain at uniaxial compressive strength | 0.00133 | -- |
| Plastic strain at transition from power law to exponential softening | 0.00293 | -- |
| Relative stress level at start of nonlinear hardening | 0.33 | -- |
| Residual relative stress level at transition from power law to exponential softening | 0.85 | -- |
| Residual compressive relative stress | 0.2 | -- |
| Mode I area-specific fracture energy (J/m²) | 100 | -- |
| Residual tensile relative stress | 0.1 | -- |
| Material Properties for Reinforcing Steel | |
|---|---|
| Young's Modulus (GPa) | 200 |
| Poisson's Ratio | 0.3 |
| Density (Kgm-3) | 7820 |
| Tensile strength (MPa) | 500 |
| Tangent modulus (MPa) | 1740 |
In addition to the concrete material with the specifications above, a second concrete material with linear properties is also needed for the "LinearLayer" named selection. It can be created in the tab of Workbench by duplicating the concrete material and removing all nonlinear material properties. To assign the correct material properties to the linear and nonlinear concrete layers, right-click the Materials folder in the Mechanical Application object tree and select insert to create two Material Assignment Objects. Rename the first one "ConcreteLinear" and scope it to the "LinearLayer" named selection. Similarly, rename the second "Concrete" and scope it to the "Non-LinearLayer" named selection.