The structural analysis software RFEM 6 is the basis of a modular software system. The main program RFEM 6 is used to define structures, materials, and loads of planar and spatial structural systems consisting of plates, walls, shells, and members. The program also allows you to create combined structures as well as to model solid and contact elements.
RSTAB 9 is a powerful analysis and design software for 3D beam, frame, or truss structure calculations, reflecting the current state of the art and helping structural engineers meet requirements in modern civil engineering.
Do you often spend too long calculating cross-sections? Dlubal Software and the RSECTION stand-alone program facilitate your work by determining section properties of various cross-sections and performing a subsequent stress analysis.
Do you always know where the wind is blowing from? From the direction of innovation, of course! With RWIND 3, you have a program at your side that uses a digital wind tunnel for the numerical simulation of wind flows. The program simulates these flows around any building geometry and determines the wind loads on the surfaces.
Are you looking for an overview of snow load zones, wind zones, and seismic zones? Then you are in the right place. Use the Geo-Zone Tool to determine quickly and efficiently snow loads, wind speeds, and seismic data according to ASCE 7‑16 and other international standards.
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If you want to specify your own design results for a structural component of one design situation type for different configurations, the "Construction Stages Analysis (CSA)" add-on provides a solution. Among other things, this add-on allows you to perform a parallel simulation of a model with a constant number of objects. In this special case, the base model is internally juxtaposed several times, and can thus be transferred to the design with differently set design configurations.
For the conversion, you can proceed as follows:
When designing cross-laminated timber (CLT) panels, the calculated moment capacities in the major strength direction (β = 0°) should be multiplied by 0.85 for conservatism according to the American National Standard Institute ANSI/APA PRG 320.
This value is known as the conservatism factor, Ccon in the Timber Design add-on and can be adjusted under the Strength Configuration for NDS.
In the serviceability limit state design 1b), the deformation wfin is calculated from the deformation components wcreep and winst. The creep deformation wcreep includes the deformation coefficient kdef. This depends on the material used and on the service class.
The deformation coefficient kdef is preset with the value of 0.6. It does not change automatically with regard to the respective service class. If it is necessary to use a different kdef value for the serviceability limit state design, you can adjust the settings of the National Annex accordingly. Pay attention to which structural component corresponds to the worst (highest) service class.
In the Steel Joints add-on, the order of components plays an important role when editing a joint: It "runs" from top to bottom.
For example, if you want to edit a plate, you have to define the "Plate" in the list of components first, before defining the "Plate Editor" component. The same principle applies to other components, such as "Plate Cut".
The attached video shows in detail how to proceed when modeling without using the component library.
The most likely cause of the different results is that you have probably not set the same smoothing of the surface internal forces.
This can be set separately in RFEM 6 and in the add-on.
If the smoothing is the same in both settings, the stresses are also the same.
For the CSA O86 and NDS, the Modification and Adjustment factors used in the Timber Design add-on in RFEM 6 can be manually adjusted. The factors are listed under the material properties.
To edit them manually, first open the material(s) being used for timber design and then set them to "User-Defined". Once this is done, navigate to the Timber Design tab where the Modification and Adjustment factors can be entered manually.
The Calculation for Torsion in the NDS Strength Configuration works together with the torsion limit set to ensure the safety of the member and structure. Below, you find a short explanation for each option:
Check torsional limit only:The ratio torsion check is compared to the torsion limit. If the ratio is smaller than the limit, then no further calculation is carried out. If the ratio is bigger than the torsion limit, an error will be shown in the design check. The error is then the most governing design check in the graphical and tabular results.
According to Timber Construction Manual:Torsion design is according to the Timber Construction Manual 4.6, and the result is a typical design ratio based on the calculation.
Ignore torsion:This setting is very similar to the first option. The ratio is compared from the torsion calculation to the torsion limit. If the ratio is smaller than the limit, then no further calculation is carried out. If the ratio is bigger than the limit, then a warning is shown in the design check. This warning will not be a governing design check in the results tables or graphics and serves only as a warning for safety considerations.
To neglect all torsion for the member design check, the limit value for torsion must be increased.
Both RFEM and RSTAB provide solution: There are numerous European and international standards as well as add-ons available for both programs that can facilitate your daily design work of aluminum and lighweight structures.
Main Programs RFEM and RSTAB
The main programs RFEM and RSTAB are used to define the model with its properties and actions. In addition to spatial beam structures, such as scaffolding or frame structures, you can also model membrane structures with RFEM. Thus, RFEM is the more versatile variant—especially if you work in other areas, such as solid construction.
Available Standards
Add-ons for Aluminum and Lightweight Structure
Design add-ons supplement the functionality of the main programs. Use the Aluminum Design add-on to perform the ultimate and serviceability limit state design, as well as the stability analysis according to the standards listed above. The Torsional Warping (7 DOF) add-on allows you to also perform lateral-torsional buckling analysis with up to seven degrees of freedom.
The design checks can be carried out for a large number of standardized and parameterized cross-sections. Lightweight structures often includes special cross-sections, such as extruded sections. You can define it with the program RSECTION and use it for the design in RFEM or RSTAB.
In the case of membrane and cable structures, the Form-Finding add-on facilitates your task to determine the shape of member and surface models subjected to axial forces.
In case of any questions about the Dlubal solution for aluminum and lightweight structures, our sales team will be happy to assist you.
RFEM allows you to perform structural analysis and design of laminate and sandwich structures. The same applies to the cross-laminated timber. Stress and deflection analysis of laminate and sandwich surfaces is performed according to the laminate theory, taking into account the shear coupling.
Programs and Add-ons
RFEM is the main program that you can use to define the model and actions. You can model planar and spatial structures, consisting of plates, walls, shells, and members.
For the stress and deflection analysis, you need the Multilayer Surfaces add-on. It allows you to define and analyze layer structures.
Use the Timber Design add-on to also design the member supporting elements of the structure according to Eurocode 5 or ANSI/AWC NDS, for example.
Dynamic Analysis
If you need to perform a seismic or vibration analysis, the corresponding Dynamic Analysis add-ons are the perfect tools for determining natural frequencies and mode shapes, or for the analysis of external excitations.
In case of any questions about the Dlubal timber design solutions, our sales team will be happy to assist you.
The Form-Finding add-on is available for the structural FEA software RFEM, which you can use to search for the shape of a tensile membrane structure before the actual design.
Once you have modeled a supporting structure or a substructure in RFEM and defined membrane surfaces, you can analyze the global model according to the large deformation analysis.
Use the main program RFEM to define the model, including the properties and actions.
The Form-Finding add-on allows you to determine a shape of the member and surface models subjected to axial forces.
Use the RWIND program to perform simulations in the digital wind tunnel for complex structures and to transfer the generated wind loads to RFEM.
Depending on the design, you can use the add-ons Steel Design and Aluminum Design to design the structure.
If a seismic or vibration analysis is required, the Dynamic Analysis add-ons are the perfect tools for this.
In case of any questions about the Dlubal solution for tensile membrane structures, our sales team will be happy to assist you.