You can perform the calculation of the warping torsion on the entire system. Thus, you consider the additional 7th degree of freedom in the member calculation. The stiffnesses of the connected structural elements are automatically taken into account. It means, you don't need to define equivalent spring stiffnesses or support conditions for a detached system.
You can then use the internal forces from the calculation with warping torsion in the add-ons for the design. Consider the warping bimoment and the secondary torsional moment, depending on the material and the selected standard. A typical application is the stability analysis according to the second-order theory with imperfections in steel structures.
Did you know that The application is not limited to thin-walled steel cross-sections. Thus, it is possible for you, for example, to perform the calculation of the ideal overturning moment of beams with solid timber cross-sections.
Compared to the RF-/STEEL Warping Torsion add-on module (RFEM 5 / RSTAB 8), the following new features have been added to the Torsional Warping (7 DOF) add-on for RFEM 6 / RSTAB 9:
Complete integration into the environment of RFEM 6 and RSTAB 9
7th degree of freedom is directly taken into account in the calculation of members in RFEM/RSTAB on the entire system
No more need to define support conditions or spring stiffnesses for calculation on the simplified equivalent system
Combination with other add-ons is possible, for example for the calculation of critical loads for torsional buckling and lateral-torsional buckling with stability analysis
No restriction to thin-walled steel sections (it is also possible to calculate ideal overturning moments for beams with massive timber sections, for example)
Are you ready for the evaluation? Use the calculation diagrams, which show the distribution of a specific result during the calculation.
You can freely define the layout of the vertical and horizontal axes of the calculation diagram. This allows you, for example, to consider the settlement distribution of a certain node, depending on the load.
Consideration of 7 local deformation directions (ux, uy, uz, φx, φy, φz, ω) or 8 internal forces (N, Vu, Vv, Mt,pri, Mt,sec, Mu, Mv, Mω) when calculating member elements
Usable in combination with a structural analysis according to linear static, second-order, and large deformation analysis (imperfections can also be taken into account)
In combination with the Stability Analysis add-on, allows you to determine critical load factors and mode shapes of stability problems such as torsional buckling and lateral-torsional buckling
Consideration of end plates and transverse stiffeners as warping springs when calculating I-sections with automatic determination and graphical display of the warping spring stiffness
Graphical display of the cross-section warping of members in the deformation
Did you use the eigenvalue solver of the add-on to determine the critical load factor within the stability analysis? In this case, you can then display the governing mode shape of the object to be designed as a result.
The Aluminum Design add-on provides you with further options. Here you can also design general cross-sections that are not predefined in the cross-section library. For example, create a cross-section in the RSECTION program and then import it into RFEM/RSTAB. Depending on the design standard used, you can select from various design formats. This includes, for example, the equivalent stress analysis.
With a license for RSECTION and "Effective Sections", you can also perform the design checks while taking into account the effective cross-section properties according to EN 1993‑1‑5.
Do you want to model and analyze the behavior of a soil solid? To ensure this, special suitable material models have been implemented in RFEM. You can use the modified Mohr-Coulomb model with a linear-elastic ideal-plastic model or a nonlinear elastic model with an oedometric stress-strain relation. The limit criterion, which describes the transition from the elastic area to that of the plastic flow, is defined according to Mohr-Coulomb.
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, or 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)
The soil solids that you want to analyze are summarized in soil massifs.
Use the soil samples as a basis for a definition of the respective soil massif. This way, the program allows for user-friendly generation of the massif, including the automatic determination of the layer interfaces from the sample data, as well as the groundwater level and the boundary surface supports.
Soil massifs provide you with the option to specify a target FE mesh size independently of the global setting for the rest of the structure. You can thus consider the various requirements of the building and soil in the entire model.
Your data are always documented in a multilingual printout report. You can adjust the content at any time and save it as a template. You can also add graphics, texts, MathML formulas, and PDF documents to your report with just a few clicks.
Compared to the RF‑/ALUMINUM add-on module (RFEM 5 / RSTAB 8), the following new features have been added to the Aluminum Design add-on for RFEM 6 / RSTAB 9:
In addition to Eurocode 9, the US standard ADM 2020 is integrated.
Consideration of the stabilizing effect of purlins and sheets by rotational restraints and shear panels
Graphical display of the results in the gross section
Output of the used design check formulas (including a reference to the used equation from the standard)
The Torsional Warping (7 DOF) add-on allows you to perform the calculation of member structures in RFEM and RSTAB, taking into account the cross-section warping. You can consider all internal forces (N, Vu, Vv, Mt,pri, Mt,sec, Mu, Mv, Mω) determined in this way in the equivalent stress analysis of the aluminum design. Note: This feature is not yet available for the design standard ADM 2020.
Do you know exactly how the form-finding is performed? First, the form-finding process of the load cases with the load case category "Prestress" shifts the initial mesh geometry to an optimally balanced position by means of iterative calculation loops. For this task, the program uses the Updated Reference Strategy (URS) method by Prof. Bletzinger and Prof. Ramm. This technology is characterized by equilibrium shapes that, after the calculation, comply almost exactly with the initially specified form-finding boundary conditions (sag, force, and prestress).
In addition to the pure description of the expected forces or sags on the elements to be formed, the integral approach of the URS also enables a consideration of regular forces. In the overall process, this allows, for example, for a description of the self-weight or a pneumatic pressure by means of corresponding element loads.
All these options give the calculation kernel the potential to calculate anticlastic and synclastic forms that are in an equilibrium of forces for planar or rotationally symmetric geometries. In order to be able to realistically implement both types individually or together in one environment, the calculation provide you with two ways to describe the form-finding force vectors:
Tension method - description of the form-finding force vectors in space for planar geometries
Projection method - description of the form-finding force vectors on a projection plane with fixation of the horizontal position for conical geometries
You already know that it is possible to model and analyze a soil and a structure in the entire model. As a result, you have explicitly taken into account the soil-structure interaction. By modifying a component, you achieve the immediate correct consideration in the analysis as well as in the results for the entire system of the soil and structure.
A graphical and tabular output of the results for deformations, stresses, and strains helps you when determining the soil solids. To achieve this, use the special filter criteria for targeted selection of results.
The program doesn't leave you alone with the results. If you want to graphically evaluate the results in the soil solids, you can use the guide objects. For example, you can define clipping planes. This allows you to view the corresponding results in any plane of the soil solid.
And not just that. The utilization of result sections and clipping boxes facilitates the precise graphical analysis of the soil solid.
Did you know? You can enter the soil layers that you have obtained from the subsoil expertises done in the locations into the program in the form of soil samples. Assign the explored soil materials, including their material properties, to the layers.
For the definition of the samples, you can enter the data in tables as well as in the respective editing dialog box. Furthermore, you can also specify the groundwater level in the soil samples.
The Ponding load type allows you to simulate rain actions on multi-curved surfaces, taking into account the displacements according to the large deformation analysis.
This numerical rainfall process examines the assigned surface geometry and determines which rainfall portions drain away and which rainfall portions accumulate in puddles (water pockets) on the surface. The puddle size then results in a corresponding vertical load for the structural analysis.
For example, you can use this feature in the analysis of approximately horizontal membrane roof geometries subjected to rain loading.
Compared to the RF-FORM-FINDING add-on module (RFEM 5), the following new features have been added to the Form-Finding add-on for RFEM 6:
Specification of all form-finding load boundary conditions in one load case
Storage of form-finding results as initial state for further model analysis
Automatic assignment of the form-finding initial state via combination wizards to all load situations of a design situation
Additional form-finding geometry boundary conditions for members (unstressed length, maximum vertical sag, low-point vertical sag)
Additional form-finding load boundary conditions for members (maximum force in member, minimum force in member, horizontal tension component, tension at i-end, tension at j-end, minimum tension at i-end, minimum tension at j-end)
Material types "Fabric" and "Foil" in material library
Parallel form-findings in one model
Simulation of sequentially building form-finding states in connection with the Construction Stages Analysis (CSA) add-on
Once you activate the Form-Finding add-on in the Base Data, a form-finding effect is assigned to the load cases with the load case category "Prestress" in conjunction with the form-finding loads from the member, surface, and solid load catalog. This is a prestress load case. It thus mutates into a form-finding analysis for the entire model with all member, surface, and solid elements defined in it. You reach the form-finding of the relevant member and membrane elements amid the overall model by using special form-finding loads and regular load definitions. These form-finding loads describe the expected state of deformation or force after the form-finding in the elements. The regular loads describe the external loading of the entire system.
You know for sure that when connecting tension-loaded components with bolted connections, you need to consider the cross-section reduction due to the bolt holes in the ultimate limit state design. The structural analysis programs also have a solution for this. In the Aluminum Design add-on, you can enter a member local section reduction for this. Enter the reduction of the cross-section as an absolute value or as a percentage of the total area at all relevant locations.
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.
Was your design successful? Very good, now comes the relaxed part. Because the program gives you the performed design checks in a table. You can display all result details in detail here. The clearly presented design formulas ensure that you will be able to understand the results without any problems. There is no black-box effect with Dlubal Software.
The design checks are carried out at all governing locations of the members and displayed graphically as a result diagram. You can find more detailed graphics in the result output. This includes the stress distribution on the cross-section or the governing mode shape, for example.
All input and result data are part of the RFEM/RSTAB printout report. You can select the report contents and extent specifically for the individual design checks.
The form-finding process gives you a structural model with active forces in the "prestress load case" This load case shows the displacement from the initial input position to the form-found geometry in the deformation results. In the force or stress-based results (member and surface internal forces, solid stresses, gas pressures, and so on), it clarifies the state for maintaining the found form. For the analysis of the shape geometry, the program offers you a two-dimensional contour line plot with the output of the absolute height and an inclination plot for the visualization of the slope situation.
Now, a further calculation and structural analysis of the entire model is performed. For this purpose, the program transfers the form-found geometry including the element-wise strains into a universally applicable initial state. You can now use it in the load cases and load combinations.
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.
Use the Time-Dependent Analysis (TDA) add-on to consider the time-dependent material behavior of members and surfaces. Long-term effects, such as creep, shrinkage, and aging, can influence the distribution of internal forces, depending on the structure. Prepare for this optimally with this add-on.
A wide range of available sections, such as rolled I-sections; channel sections; T-sections; angles; rectangular and circular hollow sections; round bars; symmetrical and asymmetrical, parametric I-, T-, and angle sections; built-up cross-sections (suitability for design depends on the selected standard)
Design of general RSECTION cross-sections (depending on the design formats available in the respective standard); for example, equivalent stress design
Design of tapered members (design method depending on the standard)
Adjustment of the essential design factors and standard parameters is possible
Flexibility due to detailed setting options for basis and extent of calculations
Fast and clear results output for an immediate overview of the result distribution after the design
Detailed output of the design results and essential formulas (comprehensible and verifiable result path)
Numerical results clearly arranged in tables and graphical display of the results in the model
Integration of the output into the RFEM/RSTAB printout report
You can find the design checks displayed in tables in the Aluminum Design add-on. Moreover, you can display the distribution of the design ratios graphically. Extensive filter options are available for you both in the table as well as in the graphical output. You can thus specifically display the desired design checks by limit state or design type in the program.