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)
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AnswerGlass structures can be calculated in RFEM with the RF-GLASS add-on module. It is possible to carry out the calculation and design on the entire model or separately.
An extensive material library contains many of the commercially available glass types, foils, and gases.
Define nodes or lines for the support of glass surfaces or model solids. The results include stresses in surfaces and solids.
To calculate glass, you need RFEM as the basis. In addition, RFEM offers a variety of options for the calculation and design of solid, steel or timber structures
Basic program RFEM
Calculation of stresses and deformations on arbitrarily shaped and also curved glass surfaces.
- DIN 18008: 2010-12
- TRLV: 2006-08
The stiffness modifications can be controlled separately for the following elements:
The first option 'Materials' is only activated for load combinations by default (see Figure 02) because the second-order analysis is preset for this. When the function is activated, the stiffness of all elements is reduced by the partial safety factor of the material (see Figure 03). This is especially important for timber construction in Europe. If the automatic load combination was selected for the standard EN 1990 + EN 1995, SIA 260 + SIA 265 or DIN 1055-100 + DIN 18008, the default settings are different. Provided that the partial safety factor of the material is defined as 1.0, it does not matter if the function is activated or not.
Use this option to control the multiplication factors of individual cross-sections. In the 'Modify' tab of the 'Edit Cross-Section' dialog box, it is possible to adjust the moments of inertia as well as cross-section surfaces. This affects the stiffness of the cross-sections.
When editing a member, the 'Modify Stiffness' dialog tab is available. There are various definition types (see Figure 05). The "Multiplication Factors" option allows you to modify the stiffness of individual members in analogy to the cross-sections.
For surfaces referred to as 'Standard' and 'Without Tension', the stiffness of the surface can be adjusted in the 'Modify Stiffness' tab of the 'Edit Surface' dialog box. There, it is possible to modify the stiffness matrix elements by a factor (as with orthotropic surfaces).
Further options for stiffness modification
Additionally, a further option can be selected in the calculation parameters to adjust specifically stiffness of other elements (see Figure 07). When selecting the 'Modify stiffness' option, a new tab opens (see Figure 08). In addition to the member and surface stiffnesses, it is also possible to adjust the stiffnesses of supports and hinges individually.
Interactions of individual factors
If several factors have been defined for an element (e.g. cross-section and member), they are multiplied by each other. For the example shown in Figure 09:
Global control of stiffness modification
In the global calculation parameters (see Figure 10), it is possible to deactivate all options mentioned above at once. The local settings in the calculation parameters of the load cases or the load combinations are ignored.
AnswerThe same requirements apply for a layered FE mesh as for a contact solid (see the links below this FAQ). If the requirements are not met, the layered FE mesh must be deactivated in the layer layout details (see Figure 02).
AnswerWith the FE mesh refinement, it is also possible to create an aligned FE mesh in the program. Thus, the automatic FE mesh generator can be controlled to a certain extent. However, it is not possible to use it for setting of a specified mesh geometry.
AnswerIf there is an insulated glass unit selected for design in RF‑GLASS, the method of the large deformation analysis is set by default. Based on the existing gas volume in the space between glass panes, this method of analysis is also required and cannot be changed.
The online service "Snow, Wind and Seismic Zones" graphically displays structural loads according to the standards of relevance to the user on the Google Maps tab and shows the site-specific structural loads for an explicit location on the map.Based on the national references of the standards used, the online service provides information about each of the load types described in the standard. If the standard specifies no data for a specific load type, the online service does not provide any further information for this load type (e.g. snow loads in the African desert).If a particular structural load standard is not offered in the Online Services selection boxes, this standard is not yet incorporated. Our team strives to expand the online service for all relevant countries around the world and to maintain the portfolio. The implementation priorities are geared to the needs of the user and the mandatory maintenance and renovation work.
Yes, you can define the required composition of the glass pane in Window '1.2 Layers'. In order to define the insulating glass, it is necessary to assign at least one glass layer to the composition. Then, you receive an additional option for the gas layer.
After entering the gas layer, additional tabs appear where you can enter further specific data for the design.
Yes, it does. Since the determination of the allowable limit stress for various glass units applies different GammaM factor according to DIN 18008, this is also included in our material library. However, the consequence if this is that by activating this option, the stiffness of the structural system is reduced by this factor.
Especially in the case of the analysis of solid loads (climatic loads), the reduced stiffness of the system has also effect on the calculated stresses and deformations.
In the case of the glass design using the RF-GLASS add-on module, the layer composition is defined in the add-on module (Window 1.2). The layer composition in the main window of RFEM is irrelevant in this case as the add-on module creates a temporary calculation model during the calculation. It is only important to define the Glass surface stiffness (see the figure).
The same applies to the support of the pane. This is also defined completely in RF‑GLASS.
On our website, you can find an interesting webinar about the 'Design of Glass Structures in RFEM' using RF‑GLASS.
By selecting the 'Thermally Toughened' check box, it is possible to consider the toughening for the ultimate limit state design (see the figure). If you select this option, Formula (2) (8.3.6/DIN18008‑1:2010‑12) will be used; otherwise Formula (3) applies.
When selecting the material, it is preselected by default, but can be be adjusted by user-defined settings.
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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.
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