Plastic Analysis
Contents
The Plastic analysis method in FEM-Design enables detailed modelling and simulation of material nonlinearities in reinforced concrete shells and structural steel bars and shells.
FEM-Design 24 introduces significant advances in Plastic analysis with new calculation options, an updated setup interface for improved usability, and enhanced result visualization and listing capabilities.
New calculation options
Concrete material model
Several new parameters and options have been added to improve the accuracy and flexibility of reinforced concrete plastic analysis:
- A new effectiveness factor type, aligned with Eurocode 2 (EN 1992-1-1:2023) can be chosen which is based on the principal strains.
- A new reduction factor can now be applied to the yield stress of rebars under compression, enabling more realistic modeling of compressed reinforcement behavior.
- Hardening behavior in reinforcement steel can now be included in non-linear plastic shell analysis.
Steel material model
For structural steel shells, a new option allows us to account for transverse shear stresses in flow rule with either constant or parabolic distributions.
- Constant: The out-of-plane total shear strains (γxz, γyz) can be considered as constant value across thickness in each layer.
- Parabolic: The shear strain distribution can be considered as an equivalent parabolic pattern.
General improvements
- Factory reset and Wiki integration: A new Reset table to factory settings button allows us to restore default parameters for concrete and structural steel plastic data. Additionally, a Factory settings info button links directly to a comprehensive online FEM-Design Wiki for further guidance.
- Tooltips for settings: Detailed tooltips now accompany each parameter in the Plastic data dialogs, providing quick and clear explanations.
- Company settings integration: Pre-saved company settings streamline Plastic data setup, improving consistency across projects.
New results
Enhanced visualization and result reporting enable a deeper understanding of material behavior. For both reinforced concrete and structural steel shells, we can display and view detailed stress and strain distributions along the thickness/layers of the shell at selected integration points. The results provided with the Detailed result tool include:
- Stress and strain components in every layer, including reinforcement layers (if applicable)
- Global coordinates of the integration point
- The number of the specific finite element to which the selected integration point belongs
- Shell material, thickness and local coordinate systems
- Reinforcement directions
- Internal forces (stress resultants) at the integration point without averaging or smoothing
- Equivalent reinforcement data, such as areas, positions from mid-plane, yield stresses including anchorage length effect and reduction factor on compressed rebars, and ultimate stresses (considering hardening and anchorage length effects)
New documentation items
The following data and results of plastic structures can now be listed in project documentation, enhancing reporting capabilities:
- Plastic data for shells
- Concrete/Steel stresses and strains
- Reinforcement stresses and strains
- Integration point details
FEM-Design also offers documentation templates for the plastic analysis of concrete and steel shell structures. These templates provide a structured format for presenting detailed results, including stress and strain distributions, and other relevant data. You can easily customize these templates to align with project-specific requirements, ensuring that the documentation meets both technical standards and your expectations.
