Dlubal RFEM 5 – Adjusting Direction of Finite Element Axis from Surfaces to Lines

Dlubal RFEM 5 - Adjusting Direction of Finite Element Axis from Surfaces to Lines

Dlubal RFEM 5 – Adjusting Direction of Finite Element Axis from Surfaces to Lines

By Ulrich Lex, Dlubal Software

It is often necessary to adjust the FE mesh of surface elements to the geometric structure. RFEM provides various options for this. For example, the FE axis can be rotated about a point, aligned in the direction of a point, or orientated to a user-defined coordinate system. Another option is the direction parallel to a line, and particularly in this case, it is possible to enter or select several lines.

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Dlubal RFEM 5 – Reduction of Loads Generated in RF-MOVE Surfaces Using RF-INFLUENCE

Dlubal RFEM 5 - Reduction of Loads Generated in RF-MOVE Surfaces Using RF-INFLUENCE

Dlubal RFEM 5 – Reduction of Loads Generated in RF-MOVE Surfaces Using RF-INFLUENCE

By Adrian Langhammer, Dlubal Software

For the reduction of loads generated in RF-MOVE Surfaces, it is possible to consider influence surfaces of a selected point. The influence surfaces are determined by RF-INFLUENCE. This procedure is useful in cases where only unfavorable acting loads should be considered. Depending on the unfavorable action, you should select the positive or negative direction.

In the example shown in the figure, there are loads to be generated on a system of two continuous panels, which cause negative deformation in the middle of the first panel. Considering this, RF-MOVE Surfaces creates the loads only in the second panel along the selected line.

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Dlubal RFEM 5 – Design of Curved Chair in RF-LAMINATE

Dlubal RFEM 5 - Design of Curved Chair in RF-LAMINATE

Dlubal RFEM 5 – Design of Curved Chair in RF-LAMINATE

By Bastian Kuhn, Dlubal Software

In RF-LAMINATE, it is possible to design also curved quadrangular surfaces. In the example in the figure, the cross-laminated timber layers of a chair are designed.

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Dlubal RFEM 5 – Consideration of Effects From Second Order Theory in RF-FOUNDATION Pro

Dlubal RFEM 5 - Consideration of Effects From Second Order Theory in RF-FOUNDATION Pro

Dlubal RFEM 5 – Consideration of Effects From Second Order Theory in RF-FOUNDATION Pro

By Paul Kieloch, Dlubal Software

In RFEM and RSTAB, the internal forces of individual load combinations are determined according to the second-order analysis by default. If you use the RF-CONCRETE add-on module for stability analysis of reinforced concrete columns, you can change the calculation method of LCs to the linear static analysis, since the effects of the second-order analysis are already considered in the calculation according to the model column method in RF-CONCRETE Columns (nominal curvature method).

In the case of using the results of such load combinations for design in RF-FOUNDATION Pro, the effect of the second-order analysis is missing in the foundation design. The reason is that the RF-FOUNDATION Pro module uses support reactions of individual LCs for the design.

In order to consider the support moments according to the second-order analysis anyway, RF-FOUNDATION Pro provides the option to affect the support moments according to the linear static analysis by a user-defined factor. You can enter these increment factors separately for both design directions in the “Details” dialog box of the RF-FOUNDATION Pro add-on module. Please note that this entry applies to the entire design case.

If there is a moment applied with a certain factor, it will be recorded in the design details and in result tables of the printout report by entering the multiplication factor.

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Designed with Dlubal Software: BVB-FanWelt in Dortmund

Designed with Dlubal Software: BVB-FanWelt in Dortmund

Designed with Dlubal Software: BVB-FanWelt in Dortmund

By Andreas Hörold, Dlubal Software

Right at the start of the German Bundesliga season 2014/15, the new BVB-FanWelt at the Signal Iduna Park was opened. It is not intended to use the open and generously designed building only for merchandising but also to give the BVB fans the possibility to discover and experience a lot of things, for example the stylized south stand, the legendary “yellow wall”.

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Dlubal RFEM 5 & RSTAB 8 – Single or Articulated Member in Stability Analysis of Double Angles in RF-/STEEL EC3

Dlubal RFEM 5 & RSTAB 8 - Single or Articulated Member in Stability Analysis of Double Angles in RF-/STEEL EC3

Dlubal RFEM 5 & RSTAB 8 – Single or Articulated Member in Stability Analysis of Double Angles in RF-/STEEL EC3

By Sebastian Hawranke, Dlubal Software

A previous post describes the stability analysis of double angles. It dealt with the analysis performed on a single member.

Now the question is, under which boundary conditions is this actually allowed. EN 1993-1-1, Clause 6.4.4, provides design rules for so-called “closely spaced built-up members”. Double angles with the back-to-back arrangement must be always connected by screws or welded tie plates. The maximum spacing between interconnections is defined as 15 times the minimum radius of gyration of one angle. There are no specific values for the space between members, but it should be in the range of usual filler plate thicknesses.

If these limits are exceeded, you have to design an articulated member. In principle, the global internal forces can be determined on a single member. In addition to pre-deformations, you should also consider the shear stiffness. This can be controlled by the value t* in RFEM and RSTAB (see the figure). This value is applied when calculating the shear area and depends on the design of bracing or framing. Formulas for t*, are described in Petersen: Steel Construction, 4th Edition, Table 17.1 (t* is indicated as tE here), for example.

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Dlubal RFEM 5 – Smoothing Options in RF-STEEL Surfaces

Dlubal RFEM 5 - Smoothing Options in RF-STEEL Surfaces

Dlubal RFEM 5 – Smoothing Options in RF-STEEL Surfaces

By Thomas Günthel, Dlubal Software

Just like in the Display navigator of RFEM, you can set the distribution of internal forces within surfaces also in RF-STEEL Surfaces. Since the result of the FEM calculation is always deformations, the corresponding forces will be recalculated. It means that the internal forces on a FEM element are calculated depending on the composition (triangle or square) at three or four places. In order to obtain continuous internal forces and thus a smoothed distribution, these internal forces have to be interpolated. The interpolation is possible by selecting the option “Distribution of internal forces” within surfaces.

The advantage of the interpolated distribution is the compliance with the distribution of a refined mesh. Accordingly, the disadvantage is that this distribution does not correspond exactly with the calculation result. Therefore, it is important for the analysis of critical points to always use a refined mesh. For example, when using a plastic material, the real plastic limit stress is displayed correctly only if you select the option “Constant on elements”.

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Dlubal RFEM 5 & RSTAB 8 – Additional Dead Loads on Platforms in RF-/TOWER Loading

Dlubal RFEM 5 & RSTAB 8 - Additional Dead Loads on Platforms in RF-/TOWER Loading

Dlubal RFEM 5 & RSTAB 8 – Additional Dead Loads on Platforms in RF-/TOWER Loading

By Wieland Götzler, Dlubal Software

As of RFEM 5.04.0024 and RSTAB 8.04.0024, there is a new feature in RF-/TOWER Loading, which allows you to define additional surface loads in a load case for dead loads, for example from grids on platforms.

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Dlubal RSTAB 8 – Certification for Russia

Dlubal RSTAB 8 - Certification for Russia

Dlubal RSTAB 8 – Certification for Russia

By Andreas Hörold, Dlubal Software

After the certification of RFEM and RF-STEEL SP , RSTAB and STEEL SP are now also available. The certificates apply to the following standards:
~ SP 20.13330.2011 (SNIP 2.01.07-85*) – Loads and effects
~ SP 16.13330.2011 (SNIP II-23-81*) – Steelwork
~ SP 53-102-2004 – General rules for designing steel structures

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Dlubal RFEM 5 – Boolean Operation “Intersect”

Dlubal RFEM 5 - Boolean Operation "Intersect"

Dlubal RFEM 5 – Boolean Operation “Intersect”

By Walter Fröhlich, Dlubal Software

The “Intersect” option may facilitate modeling of complex solids. This option is available in the shortcut menu after selecting two solids.

In the example shown in the figure, two single solids were created at first. The first solid represents the thickness of the element, the second solid represents the view. Then, both elements were superimposed and combined to form one solid.

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