- Analysis of time diagrams and accelerograms (acceleration-time diagrams exciting the supports of a structure)
- Combination of user-defined time diagrams with nodal, member, and surface loads, as well as free and generated loads
- Combination of several independent excitation functions
- Linear implicit Newmark analysis or modal analysis in time history
- Structural damping using Raleigh damping coefficients or Lehr's damping value
- Graphical display of results in calculation diagrams
- Result display in individual time steps or as an envelope during the entire time period
- Extensive library of seismic events (accelerograms)
You can simulate the static friction effects between two supporting components along a line using the "Friction" nonlinearity in the Line Release Type.
Use the "Import Support Reactions" Load Wizard in RFEM 6 and RSTAB 9 to easily transfer reaction forces from other models. The wizard allows you to connect all or several nodal and line loads of different models with each other in a few steps.
The load transfer from load cases and load combinations can be carried out automatically or manually. It's necessary that the models are saved in the same Dlubal Center project.
The "Import Support Reactions" load wizard supports the concept of positional statics and allows you to digitally connect the individual positions.
Go to Explanatory VideoThis function provides you with the option to adopt reaction forces from other models as nodal and line loads.
The option not only transfers the reaction load as an action, but digitally couples the support load of the original model with the load size of the target object. The subsequent changes in the original model are automatically adopted in the target model.
This technology supports the concept of positional statics and allows you to digitally connect the individual positions of the same Dlubal Center project.
Go to Explanatory VideoWould you like to display nodal loads or load components that act on one point next to each other? Then use the "Shifted Display" option. This allows you to define offsets in the x, y, and z directions, as well as the size and spacing.
Go to Explanatory VideoYou probably already know that node, line, and surface releases are used to define transfer conditions between objects. For example, you can release members, surfaces, and solids from a line. It is also easily possible for the releases to have nonlinear properties, such as "Fixed if positive n", "Fixed if negative n", and so on.
Note that the definition of the effective lengths in the Aluminum Design add-on is an essential requirement for the stability analysis. For this, define the nodal supports and effective length factors in the input dialog box. Do you want to clearly document the nodal supports and the resulting segments with the associated effective length factors? To check the input data, it is best for you to use the graphic display in the RFEM/RSTAB work window. Thus, you can comprehend the design at any time with minimum effort.
The object types listed below can be graphically assigned to the elements of the structure modeled in the program.
- Nodal supports
- Member shear panels
- Local reductions of member cross-sections
- Member transverse stiffeners
- Member longitudinal welds
- Effective lengths
- Boundary conditions
- Line supports
- Loads
- Member support
- Punching reinforcements
- Mesh refinements
- Surface reinforcements
- Surface results adjustments
- Surface support
- Service classes
- Imperfections
Do you want to consider other loads as masses in addition to the static loads? The program allows that for nodal, member, line and surface loads. For this, you need to select the Mass load type when defining the load of interest. Define a mass or mass components in the X, Y, and Z directions for such loads. For nodal masses, you have an additional option to also specify moments of inertia X, Y, and Z in order to model more complex mass points.
It is often necessary to neglect masses. This is particularly the case when you want to use the output of the modal analysis for the seismic analysis. For this, 90% of the effective modal mass in each direction is required for the calculation. So you can neglect the mass in all fixed nodal and line supports. The program automatically deactivates the associated masses for you.
You can also manually select the objects whose masses are to be neglected for the modal analysis. We have shown the latter in the image for a better view. A user-defined selection is made the and the objects with their associated mass components are selected to neglect the masses.
- Stability analyses for flexural buckling, torsional buckling, and flexural-torsional buckling under compression
- Import of the effective lengths from the calculation using the Structure Stability add-on
- Graphical input and check of the defined nodal supports and effective lengths for stability analysis
- Determination of the equivalent member lengths for tapered members
- Consideration of Lateral-Torsional Bracing Position
- Lateral-torsional buckling analysis of the structural components subjected to moment loading
- Depending on the standard, a choice between user-defined input of Mcr, analytical method from the standard, and use of internal eigenvalue solver
- Consideration of a shear panel and a rotational restraint when using the eigenvalue solver
- Graphical display of a mode shape if the eigenvalue solver was used
- Stability analysis of structural components with the combined compression and bending stress, depending on the design standard
- Comprehensible calculation of all necessary coefficients, such as the factors for considering moment distribution or interaction factors
- Alternative consideration of all effects for the stability analysis when determining internal forces in RFEM/RSTAB (second-order analysis, imperfections, stiffness reduction, possibly in combination with the Torsional Warping (7 DOF) add-on)
Do you want to perform a stability analysis in the Steel Design add-on? Then it is absolutely necessary to define the effective lengths. To do this, define the nodal supports and effective length factors in the input dialog box. For easy documentation and a comprehensible check of the entries, you can also graphically display the nodal supports and the resulting segments with the corresponding effective length factor in the work window of RFEM/RSTAB.
Always keep an eye on the stability of your structures: You can now consider eccentricities for nodal and member loads.
When starting the analysis in the RFEM or RSTAB application, you trigger a batch process. It places all member, surface, and solid definitions of the model rotated with all relevant coefficients in the numerical wind tunnel of RWIND Basic. Furthermore, it starts the CFD analysis, and returns the resulting surface pressures for a selected time step as FE mesh nodal loads or member loads into the respective load cases of RFEM or RSTAB.
These load cases which contain RWIND Basic loads can then be calculated. Moreover, you can combine them with other loads in load and result combinations.
There's something new for you! To define odal mesh refinements, the options for FE length arrangement have been added:
- Radial
- Gradually
- Combined
- 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
You have two options in RFEM. On the one hand, you can determine the punching load from a single load (from column/loading/nodal support) and the smoothed or unsmoothed shear force distribution along the control perimeter. On the other hand, you can specify them as user-defined.
Calculate the design ratio of the punching shear resistance without punching reinforcement as a design criterion and the program will deliver you the corresponding result. In the case of exceeding the punching shear resistance without punching reinforcement, the program determines the required punching reinforcement as well as the required longitudinal reinforcement for you.
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.
- Stability analyses for flexural buckling, torsional buckling, and flexural-torsional buckling under compression
- Import of the effective lengths from the calculation using the Structure Stability add-on
- Graphical input and check of the defined nodal supports and effective lengths for stability analysis
- Lateral-torsional buckling analysis of the structural components subjected to moment loading
- Depending on the standard, a choice between user-defined input of Mcr, analytical method from the standard, and use of internal eigenvalue solver
- Consideration of a shear panel and a rotational restraint when using the eigenvalue solver
- Graphical display of a mode shape if the eigenvalue solver was used
- Stability analysis of structural components with the combined compression and bending stress, depending on the design standard
- Comprehensible calculation of all necessary coefficients, such as the factors for considering moment distribution or interaction factors
- Alternative consideration of all effects for the stability analysis when determining internal forces in RFEM/RSTAB (second-order analysis, imperfections, stiffness reduction, possibly in combination with the Torsional Warping (7 DOF) add-on)
- Stability analyses for flexural buckling, torsional buckling, and flexural-torsional buckling under compression
- Lateral-torsional buckling analysis of the structural components subjected to moment loading
- Import of the effective lengths from the calculation using the Structure Stability add-on
- Graphical input and check of the defined nodal supports and effective lengths for stability analysis
- Depending on the standard, a choice between user-defined input of Mcr, analytical method from the standard, and use of internal eigenvalue solver
- Consideration of a shear panel and a rotational restraint when using the eigenvalue solver
- Graphical display of a mode shape if the eigenvalue solver was used
- Stability analysis of structural components with the combined compression and bending stress, depending on the design standard
- Comprehensible calculation of all necessary coefficients, such as interaction factors
- Alternative consideration of all effects for the stability analysis when determining internal forces in RFEM/RSTAB (second-order analysis, imperfections, stiffness reduction, possibly in combination with the Torsional Warping (7 DOF) add-on)
If you release a structural component with a nonlinear elastic material again, the strain goes back on the same path. In contrast to the Isotropic|Plastic material model, there is no strain left when completely unloaded.
You can select three different definition types:
- Standard (definition of the equivalent stress under which the material plastifies)
- Bilinear (definition of the equivalent stress and strain hardening modulus)
- Stress-Strain Diagram:
- Definition of polygonal stress-strain diagram
- Option to save / import the diagram
- Interface with MS Excel
Background information about nonlinear material models can be found in the technical article describing the yield laws in isotropic nonlinear elastic material model.
Do not lose track of stiffnesses and initial deformations. In the individual load cases or combinations, you have the option to modify the stiffnesses of materials, cross-sections, nodal, line and surface supports, and member and line hinges for all or selected members. You can also consider initial deformations from other load cases or load combinations.
If you are working with nonlinearities, this feature is suited very well to support you. For example, you can specify nonlinearities of member end releases (yielding, tearing, slippage, and so on) and supports (including friction). Furthermore, you can use special dialog boxes to determine the spring stiffnesses of columns and walls based on the geometry specifications.
Planning with members is also facilitated in the programs due to specific features. You can arrange members eccentrically, support them by elastic foundations, or define them as rigid links. Member sets allow you to easily apply the load on several members.
In RFEM, you can also define eccentricities of surfaces. Here, you can transform nodal and linear loads into surface loads. If necessary, divide surfaces into surface components and members into surfaces.
The number of degrees of freedom in a node is no longer a global calculation parameter in RFEM (6 degrees of freedom for each mesh node in 3D models, 7 degrees of freedom for the warping torsion analysis). Thus, each node is generally considered with a different number of degrees of freedom, which leads to a variable number of equations in the calculation.
This modification speeds up the calculation, especially for models where a significant reduction of the system could be achieved (for example, trusses and membrane structures).
RFEM offers the following tables to display forces and deformations of hinges and releases:
- 4.45 Line Hinges - Deformations
- 4.46 Line Hinges - Forces
- 4.47 Member Hinges - Deformations
- 4.48 Member Hinges - Forces
- 4.49 Nodal Releases - Deformations
- 4.50 Nodal Releases - Forces
- 4.51 Line Releases - Deformations
- 4.52 Line Releases - Forces
The tables can be displayed in the prinout report. Moreover, the results in line hinges and line releases can be displayed graphically. It can be controlled by Project Navigator - Results.
- Nonlinear member types, such as tension and compression members or cables
- Member nonlinearities, such as failure, tearing, yielding under tension or compression
- Support nonlinearities, such as failure, friction, diagram, and partial activity
- Release nonlinearities, such as friction, partial activity, diagram, and fixed if positive or negative internal forces
- User-defined time diagrams as a function of time, in tabular form, or as harmonic loads
- Combination of the time diagrams with RFEM/RSTAB load cases or combinations (enables definition of nodal, member, and surface loads, as well as free and generated loads varying over time)
- Combination of several independent excitation functions
- Nonlinear time history analysis with the implicit Newmark analysis (RFEM only) or the explicit analysis
- Structural damping using Rayleigh damping coefficients or Lehr's damping
- Direct import of initial deformations from a load case or combination (RFEM only)
- Stiffness modifications as initial conditions; for example, axial force effect, deactivated members (RSTAB only)
- Graphical display of results in a time history diagram
- Export of results in user-defined time steps or as an envelope
- Import of materials, cross-sections, and internal forces from RFEM/RSTAB
- Steel design of thin‑walled cross‑sections according to EN 1993‑1‑1:2005 and EN 1993‑1‑5:2006
- Automatic classification of cross-sections according to EN 1993-1-1:2005 + AC:2009, Cl. 5.5.2, and EN 1993-1-5:2006, Cl. 4.4 (cross-section class 4), with optional determination of effective widths according to Annex E for stresses under fy
- Integration of parameters for the following National Annexes:
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DIN EN 1993-1-1/NA:2015-08 (Germany)
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ÖNORM B 1993-1-1:2007-02 (Austria)
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NBN EN 1993-1-1/ANB:2010-12 (Belgium)
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BDS EN 1993-1-1/NA:2008 (Bulgaria)
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DS/EN 1993-1-1 DK NA:2015 (Denmark)
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SFS EN 1993-1-1/NA:2005 (Finland)
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NF EN 1993-1-1/NA:2007-05 (France)
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ELOT EN 1993-1-1 (Greece)
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UNI EN 1993-1-1/NA:2008 (Italy)
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LST EN 1993-1-1/NA:2009-04 (Lithuania)
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UNI EN 1993-1-1/NA:2011-02 (Italy)
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MS EN 1993-1-1/NA:2010 (Malaysia)
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NEN EN 1993-1-1/NA:2011-12 (Netherlands)
- NS EN 1993-1-1/NA:2008-02 (Norway)
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PN EN 1993-1-1/NA:2006-06 (Poland)
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NP EN 1993-1-1/NA:2010-03 (Portugal)
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SR EN 1993-1-1/NB:2008-04 (Romania)
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SS EN 1993-1-1/NA:2011-04 (Sweden)
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SS EN 1993-1-1/NA:2010 (Singapore)
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STN EN 1993-1-1/NA:2007-12 (Slovakia)
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SIST EN 1993-1-1/A101:2006-03 (Slovenia)
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UNE EN 1993-1-1/NA:2013-02 (Spain)
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CSN EN 1993-1-1/NA:2007-05 (Czech Republic)
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BS EN 1993-1-1/NA:2008-12 (the United Kingdom)
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CYS EN 1993-1-1/NA:2009-03 (Cyprus)
- In addition to the National Annexes (NA) listed above, you can also define a specific NA, applying user‑defined limit values and parameters.
- Automatic calculation of all required factors for the design value of flexural buckling resistance Nb,Rd
- Automatic determination of the ideal elastic critical moment Mcr for each member or set of members on every x-location according to the Eigenvalue Method or by comparing moment diagrams. You only have to define the lateral intermediate supports.
- Design of tapered members, unsymmetric sections or sets of members according to the General Method as described in EN 1993-1-1, Cl. 6.3.4
- In the case of the General Method according to Cl. 6.3.4, optional application of "European lateral-torsional buckling curve" according to Naumes, Strohmann, Ungermann, Sedlacek (Stahlbau 77 [2008], pp. 748‑761)
- Rotational restraints can be taken into account (trapezoidal sheeting and purlins)
- Optional consideration of shear panels (for example, trapezoidal sheeting and bracing)
- RF-/STEEL Warping Torsion module extension (license required) for stability analysis according to the second-order analysis as stress analysis including consideration of the 7th degree of freedom (warping)
- Module extension RF-/STEEL Plasticity (license required) for plastic analysis of cross‑sections according to Partial Internal Forces Method (PIFM) and Simplex Method for general cross‑sections (in connection with the RF‑/STEEL Warping Torsion module extension, it is possible to perform the plastic design according to the second‑order analysis)
- Module extension RF-/STEEL Cold-Formed Sections (license required) for ultimate and serviceability limit state designs for cold-formed steel members according to the EN 1993-1-3 and EN 1993-1-5 standards
- ULS design: Selection of fundamental or accidental design situations for each load case, load combination, or result combination
- SLS design: Selection of characteristic, frequent, or quasi-permanent design situations for each load case, load combination, or result combination
- Tension analysis with definable net cross-section areas for member start and end
- Weld designs of welded cross-sections
- Optional calculation of warp spring for nodal support on sets of members
- Graphic of design ratios on cross-section and in RFEM/RSTAB model
- Determination of governing internal forces
- Filter options for graphical results in RFEM/RSTAB
- Representation of design ratios and cross‑section classes in the rendered view
- Color scales in result windows
- Automatic cross-section optimization
- Transfer of optimized cross-sections to RFEM/RSTAB
- Parts lists and quantity surveying
- Direct data export to MS Excel
- Verifiable printout report
- Possibility to include the temperature curve in the report
- Design of members and sets of members for tension, compression, bending, shear, torsion, and combined internal forces
- Stability analysis of buckling and lateral-torsional buckling
- Automatic determination of effective radius of gyration by special integrated FEA software (eigenvalue analysis) for general loading and support conditions
- Alternative analytical calculation of effective radius of gyration for standard situations
- Optional application of discrete lateral supports to beams
- Definition of nodal supports for sets of members
- Serviceability limit state design (deflection)
- Cross-section optimization
- A wide range of available cross-sections, such as rolled I-sections, channel sections, T-sections, angles, rectangular and circular hollow sections, round bars, and many others.
- Detailed result documentation including references to design equations of the used standard
- Various filter and sorting options of results, including result lists by member, cross-sections, and x-location, or by load case, load and result combination
- Result table of member slenderness and governing internal forces
- Metric and imperial units