- Realistic representation of interaction between a building and soil
- Realistic representation of the influences of the foundation components on each other
- Extensible library of soil properties
- Consideration of several soil samples (probes) at different locations, even outside the building
- Determination of settlements and stress diagrams as well as their graphical and tabular display
Entering soil layers for soil samples is performed in a clearly arranged dialog box. A corresponding graphical representation supports clarity and makes checking the input user-friendly.
An extensible database facilitates the selection of soil material properties. The Mohr-Coulomb model as well as a nonlinear model with stress and strain dependent stiffness are available for a realistic modeling of the soil material behavior.
You can define any number of soil samples and layers. The soil is generated from all entered samples using 3D solids. Assignment to the structure is carried out using coordinates.
The soil body is calculated according to the nonlinear iterative method. The calculated stresses and settlements are displayed graphically and in tables.
- Simple definition of construction stages in the RFEM structure including visualization
- Adding, removing, modifying, and reactivating member, surface, and solid elements and their properties (for example, member and line hinges, degrees of freedom for supports, and so on)
- Automatic and manual combinatorics with load combinations in the individual construction stages (for example, to consider mounting loads, mounting cranes, and other loads)
- Consideration of nonlinear effects such as tension member failure or nonlinear supports
- Interaction with other add-ons, such as Nonlinear Material Behavior, Structure Stability, Form-Firnding, and so on.
- Display of results numerically and graphically for individual construction stages
- Detailed printout report with documentation of all structural and load data for each construction stage
Have you created the entire structure in RFEM? Very well, now you can assign the individual structural components and load cases to the corresponding construction stages. In each construction stage, you can modify release definitions of members and supports, for example.
You can thus model structural modifications, such as those that occur when bridge girders are successively grouted or when columns are settled. Then, assign the load cases created in RFEM to the construction stages as permanent or non-permanent loads.
Did you know that The combinatorics allows you to superimpose the permanent and non-permanent loads in load combinations. In this way, it is possible for you to determine the maximum internal forces of different crane positions or to consider temporary mounting loads available in one construction stage only.
If there are geometry differences arising between the ideal and the deformed structural system from the previous construction stage, they are compared in the program. The next construction stage is built on top of the stressed system from the previous construction stage. This calculation is nonlinear.
Was the calculation successful? Now you can view the results of the individual construction stages graphically and in tables in RFEM. Moreover, RFEM allows you to consider the construction stages in the combinatorics and include it in further design.
- Automatic consideration of masses from self-weight
- Direct import of masses from load cases or load combinations
- Optional definition of additional masses (nodal, linear, or surface masses, as well as inertia masses) directly in the load cases
- Optional neglect of masses (for example, mass of foundations)
- Combination of masses in different load cases and load combinations
- Preset combination coefficients for various standards (EC 8, SIA 261, ASCE 7,...)
- Optional import of initial states (for example, to consider prestress and imperfection)
- Structure Modification
- Consideration of failed supports or members/surfaces/solids
- Definition of several modal analyses (for example, to analyze different masses or stiffness modifications)
- Selection of mass matrix type (diagonal matrix, consistent matrix, unit matrix), including user-defined specification of translational and rotational degrees of freedom
- Methods for determining the number of mode shapes (user-defined, automatic - to reach effective modal mass factors, automatic - to reach the maximum natural frequency - only available in RSTAB)
- Determination of mode shapes and masses in nodes or FE mesh points
- Results of eigenvalue, angular frequency, natural frequency, and period
- Output of modal masses, effective modal masses, modal mass factors, and participation factors
- Masses in mesh points displayed in tables and graphics
- Visualization and animation of mode shapes
- Various scaling options for mode shapes
- Documentation of numerical and graphical results in printout report
In the modal analysis settings, you have to enter all data that are necessary for the determination of the natural frequencies. These are, for example, mass shapes and eigenvalue solvers.
The Modal Analysis add-on determines the lowest eigenvalues of the structure. Either you adjust the number of eigenvalues or let them determined automatically. Thus, you should reach either effective modal mass factors or maximum natural frequencies. Masses are imported directly from load cases and load combinations. In this case, you have the option to consider the total mass, load components in the global Z-direction, or only the load component in the direction of gravity.
You can manually define additional masses at nodes, lines, members, or surfaces. Furthermore, you can influence the stiffness matrix by importing axial forces or stiffness modifications of a load case or load combination.
In RFEM, you can use these three powerful eigenvalue solvers:
- Root of Characteristic Polynomial
- Method by Lanczos
- Subspace Iteration
RSTAB, on the other hand, provides you with these two eigenvalue solvers:
- Subspace Iteration
- Shifted inverse power method
The selection of the eigenvalue solver depends primarily on your model size.
As soon as the program has completed the calculation, the eigenvalues, natural frequencies and periods are listed. These result windows are integrated in the main program RFEM/RSTAB. You can find all mode shapes of the structure in tables and also have an option to display them graphically and to animate them.
All result tables and graphics are part of the RFEM/RSTAB printout report. In this way, you can ensure clearly arranged documentation. You can also export the tables to MS Excel.
Have you activated the Time-Dependent Analysis (TDA) add-on? Very well, now you can add time data to load cases. After you have defined the start and end of the load, the influence of creep at the end of the load is taken into account. The program allows you to model creep effects for frame and truss structures made of reinforced concrete.
In this case, the calculation is performed nonlinearly according to the rheological model (Kelvin and Maxwell model).
Was the calculation successful? You can now display the determined internal forces in tables and graphics, and consider them in the design.
The Dlubal structural analysis software does a lot of work for you. The input parameters, which are relevant for the selected standards, are suggested by the program in accordance with the rules. Furthermore, you can enter response spectra manually.
Load cases of the type Response Spectrum Analysis define the direction in which response spectra act and which eigenvalues of the structure are relevant for the analysis. In the spectral analysis settings, you can define details for the combination rules, damping (if applicable), and zero-period acceleration (ZPA).
Did you know that Equivalent static loads are generated separately for each relevant eigenvalue and excitation direction. These loads are saved in a load case of the Response Spectrum Analysis type and RFEM/RSTAB performs a linear static analysis.
The load cases of the type Response Spectrum Analysis contain the generated equivalent loads. First, the modal contributions have to be superimposed with the SRSS or CQC rule. In this case, you can use the signed results based on the dominant mode shape.
Afterwards, the directional components of earthquake actions are combined with the SRSS or the 100% / 30% rule.
- Artificial intelligence technology (AI): Particle swarm optimization (PSO)
- Structure optimization according to the minimum weight or deformation
- Use of any number of optimization parameters
- Specification of variable ranges
- Optimization of cross-sections and materials
- Parameter definition types
- Optimization | Ascending or Optimization | Descending
- Application of parametric models and blocks
- Code-based JavaScript parametrization of blocks
- Optimization taking into account the design results
- Tabular display of the best model mutations
- Real-time display of the model mutations in the optimization process
- Model cost estimation by specifying unit prices
- Determination of the global warming potential GWP when realizing the model by estimating the CO2 equivalent
- Specification of weight-, volume-, and area-based units (price and CO2e)
Did you know? The structural optimization in the programs RFEM and RSTAB is a completion of the parametric input. It is a parallel process beside the actual model calculation with all its regular calculation and design definitions. The add-on assumes that your model or block is built with a parametric context and is controlled in its entirety by global control parameters of the "optimization" type. Therefore, these control parameters have a lower and upper limit and a step size to delimit the optimization range. If you want to find optimal values for the control parameters, you have to specify an optimization criterion (for example, minimum weight) with the selection of an optimization method (for example, particle swarm optimization).
You can already find the cost and CO2 emission estimation in the material definitions. You can activate both options individually in each material definition. The estimation is based on a unit for unit cost or unit emission for members, surfaces, and solids. In this case, you can select whether to specify the units by weight, volume, or area.
There are two methods that you can use for the optimization process, with which you can find optimal parameter values according to a weight or deformation criterion.
The most efficient method with the littlest calculation time is the near-natural particle swarm optimization (PSO). Have you heard or read about it? This artificial intelligence (AI) technology has a strong analogy to the behavior of flocks of animals, looking for a resting place. In such swarms, you can find many individuals (cf. optimization solution - for example, weight) who like to stay in a group and follow the group movement. Let's assume that each individual swarm member has a need to rest at an optimal resting place (cf. best solution - for example, lowest weight). This need increases as the resting place is approached. Thus, the swarm behavior is also influenced by the properties of the space (cf. result diagram).
Why the excursion into biology? Quite simply – the PSO process in RFEM or RSTAB proceeds in a similar way. The calculation run starts with an optimization result from a random assignment of the parameters to be optimized. It repeatedly determines new optimization results with varied parameter values, which are based on the experience of the previously performed model mutations. The process continues until the specified number of possible model mutations is reached.
As an alternative to this method, the program also offers you a batch processing method. This method attempts to check all possible model mutations by randomly specifying the values for the optimization parameters until a predetermined number of possible model mutations is reached.
After calculating a model mutation, both variants also check the respective activated design results of the add-ons. Furthermore, they save the variant with the corresponding optimization result and value assignment of the optimization parameters if the utilization is < 1.
You can determine the estimated total costs and emission from the respective sums of the individual materials. The sums of the materials are composed of the weight-based, volume-based, and area-based partial sums of the member, surface, and solid elements.
- Stress determination using an elastic-plastic material model
- Design of masonry disc structures for compression and shear on the building model or single model
- Automatic determination of stiffness of a wall-slab hinge
- An extensive material database for almost all stone-mortar combinations available on the Austrian market (the product range is continuously being expanded, for other countries as well)
- Automatic determination of material values according to Eurocode 6 (ÖN EN 1996‑X)
- Option to create pushover analysis
You enter and model the structure directly in RFEM. You can combine the masonry material model with all common RFEM add-ons. This enables you to design the entire building models in connection with masonry.
The program automatically determines for you all parameters required for the calculation by using the material data that you have entered. Then, it finally generates the stress-strain curves for each FE element.
Was your design successful? Then just sit back and relax. You benefit from the numerous functions in RFEM also here. The program gives you the maximum stresses of the masonry surfaces, whereby you can display the results in detail at each FE mesh point.
Moreover, you can insert sections in order to carry out a detailed evaluation of the individual areas. Use the display of the yield areas to estimate the cracks in the masonry.