In addition to our technical support (e.g. via chat), you’ll find resources on our website that may help you with your design using Dlubal Software.
Frequently Asked Questions (FAQ)
Customer Support 24/7
Materials are required to define surfaces, cross-sections, and solids. The material properties affect the stiffnesses of these objects.
There are 13 material models available if you have a license for the RF‑MAT NL add-on module.
In the case of the abundance of material models, it is necessary to make sure that you assign the corresponding material model to the members and their surfaces/solids.
In the example shown here, surfaces have been generated from a member for a detailed analysis. There is still an unused cross-section defined (marked in blue) and the material is entered for the member cross-section as well as for the surfaces. When editing an existing material to Isotropic Nonlinear Elastic 2D/3D , the 2D/3D material model is also defined for the created member cross-section, which leads to the error message.
When working with members and surfaces / solids, it is recommended to create more than one material.
After generating a surface from a pipe member, this is no longer connected to the original nodal support. A line support is recommended for the newly created lines at the pipe start, see Figure 01.
Also, the nodal load is no longer connected to the original member. In this case, a crossing of rigid members is recommended for the load introduction, see Figure 02. Thus, the load is transferred to the boundary lines of the surface.
The input of intermediate lateral restraints is used to enter lateral supports on a member without having to insert a node in the model at this location. Furthermore, the design of sets of members using the equivalent member method requires them to define the existing support conditions at the intermediate nodes of the set of members.
The entered intermediate lateral restraints are then considered as additional boundary conditions in the eigenvalue solver. However, some boundary conditions are already included in the input tables of the nodal supports or the effective lengths.
To avoid conflicts or duplicate entries for the same location, the error message "Invalid location of the intermediate lateral restraints" appears. The following locations are not allowed as they are already defined in the other entries:
Design of Members:
- Start and end of a member
Design of Sets of Members:
- Start and end of all members if they are entered using nodal supports
- Start and end of a set of members for the design using the equivalent member method
However, it is very easy to find the error, because the first line with the wrong entry is automatically selected after confirming the error message.
AnswerIf you want to consider the load cases again, please perform a new RWIND Simulation calculation. If you want to perform the calculation of the existing combinations, please remove the RWIND Simulation load cases from the Wind action before deleting the FE mesh, then the combinations are created again and it is possible to perform the calculation.
In RF‑/STEEL EC3, a support has been defined in Window "1.7 Nodal Supports" at a node that is not part of the set of members. In this case, it is necessary to define the support at a node existing in the set of members or delete this nodal support in Window "1.7 Nodal Supports" of RF‑/STEEL EC3.
In Figure 1, a nodal support has been defined on Node 2 and Node 7 for Set of members 1, for example. When starting the calculation, the message "Node No. 7 with support does not exist in the set of members No. 1. Please correct this in 1.7." appears (Figure 02, Figure 03).
In Window "1.7 Nodal Supports" of RF‑/STEEL EC3, it is possible to only display the selected set of members by clicking the "Show Only Current Object" button and the node numbering can be displayed by clicking the "Local Coordinate System" button (Figure 04). It is obvious that Node 7 is not contained in the set of members. Instead of at Node 7, the support must be defined on a node contained in the member set (for example, Node 6).
In order to prevent the error message (Figure 1) to appear, and ensure that the calculation will start, it is necessary to assign the material to the corresponding point elements as follows:
- Right-click the entire cross-section: "Reduce Cross-Section into Elements," see Figure 02.
- Select the corresponding elements or all point elements with the "Insert" status by using the Views navigator, because these can be only used to define the material (in contrast to the point elements with the "Remove" status).
- Assign the corresponding material and click OK to confirm, see Figure 03.
- Deactivate the visibility.
- Select all elements and right-click one of the selected elements: "Create Cross-Section from Selected Elements," see Figure 04.
In the case of timber, the "Orthotropic Elastic/Plastic 3D" material model has to be assigned to the "Material" solid type (Figure 01).Since the program considers the "Contact" solid type as a member, it usually requires the isotropic material model (Figure 02).
AnswerThis error is displayed when importing an update that is older than the last imported update.First, check in Admin Control Center at http://localhost:1947 under Features if the purchased modules are already available.
If not all of the purchased modules are available, please follow the instructions below:Network dongle (hardware dongle):
Please send us the C2V file, which you can create by using the RUS tool, see:
https://www.dlubal.com/en-US/support-and-learning/support/faq/001479Network dongle (softlock):Please send us the C2V file, which you can create directly in the Admin Control Center, see:
In a dynamic analysis, you can only calculate as many mode shapes as the structural system has degrees of freedom. The degrees of freedom mean the number of mass points multiplied by the number of the directions in which the masses act.
A cantilever that is not split by the FE mesh has a mass point at the end. The action direction of the masses in RF‑/DYNAM Pro is limited to the X and Y direction. Thus, the system has 2 degrees of freedom, thus 2 mode shapes can only be calculated.
Please note: In this case, the selection of the method for solving eigenvalue problem is very important. In contrast to the "Root of the characteristic polynomial" method, the Lanczos method cannot calculate all eigenvalues of the system, but only n -1, which means only 1 eigenvalue in this example.
AnswerWith RF-MAT NL, we offer the use of various nonlinear material models. If members, surfaces, and/or solids are combined in RFEM, the nonlinear material models must be assigned individually for members (1D) and surfaces and solids (2D/3D).
Members as 1D elements can not be assigned a nonlinear material model (2D/3D).
Did you find your question?
If not, contact us via our free e-mail, chat, or forum support, or send us your question via the online form.
Wind Simulation & Wind Load Generation
With the stand-alone program RWIND Simulation, wind flows around simple or complex structures can be simulated by means of a digital wind tunnel.
The generated wind loads acting on these objects can be imported to RFEM or RSTAB.
“Thank you for the valuable information.
I would like to pay a compliment to your support team. I am always impressed how quickly and professionally the questions are answered. I have used a lot of software with a support contract in the field of structural analysis, but your support is by far the best. ”