FAQ 004816 | For the directions and forces, there are four options under the "Grouped" selection box to smooth the internal forces. Which grouping should I select here?

Easily learn how to work with the Dlubal Software programs

  • Dlubal Software | Videos

Video

First Steps with RFEM

First steps

We provide hints and tips to help you get started with the basic program RFEM.

Please accept Marketing Cookies to watch this video.

Question

For the directions and forces, there are four options under the "Grouped" selection box to smooth the internal forces. Which grouping should I select here?

Answer

The "Grouped" determination of internal forces is divided into four subcommands.

  1. u with my,mxy,vy,ny,nxy
  2. v with mx,mxy,vx,nx,nxy
  3. u with mx,mxy,vx,nx,nxy
  4. v with my,mxy,vy,ny,nxy

The effect of these commands is explained using a simple example.

Structure:

  • Plate as a deep beam
  • Span 9 m
  • Beam height 1.5 m
  • Concentrated load 20 kN in the middle of the span
  • FE mesh size 10 cm
Image 01 shows the maximum and the minimum internal forces at the load application point unsmoothed. Obviously, these internal forces are singular results. You can find detailed information about singularities in Technical Article 001503.

In order to completely include at least two FE elements for each side of the load introduction using the average region, an average region of 50/50 cm is defined (Image 02).

The following table shows the change of smoothing separately for each grouping. For this, the drawn upper region of the load application is only considered. Grouping 0 stands for the unsmoothed internal forces in this case.

 01234
nx 74.9 kN/m74.9 kN/m47.2 kN/m51.8 kN/m74.9 kN/m
ny109.0 kN/m26.5 kN/m109.0 kN/m109.0 kN/m5.8 kN/m
nxy75.1 kN/m30.7 kN/m15.8 kN/m30.7 kN/m15.8 kN/m

The table shows that a combination of Grouping 1 and Grouping 2 as well as Grouping 3 and Grouping 4 is always reasonable in relation to the axial forces.

Image 03 shows the averaged internal forces for Groups 1/2 and 3/4 together.

The following values are used for the combinations:

 1/23/41/2 and 3/4
nx47.2 kN/m51.8 kN/m47.1 kN/m
ny26.5 kN/m  5.8 kN/m 5.3 kN/m
nxy12.9 kN/m12.9 kN/m12.9 kN/m

As already mentioned, the combinations 1/2 and 3/4 use the minimum average internal forces of the respective grouping. The shear force nxy is calculated from the forces in the normal direction and is therefore already displayed as "smeared shear force" for the combination 1/2 and 3/4.

Conclusion

For a material with pronounced stiffness and strength directions, such as reinforced concrete or cross-laminated timber, the orientation of the strengths is relevant for the selection of the correct grouping. In the combination of group 1/2, the internal forces are smoothed in the longitudinal direction of the structural component, in group 3/4 in the transverse direction. If the structural component is oriented in the longitudinal direction as shown in Figure 4, the smoothing in the longitudinal direction is therefore recommended. However, the type of load application and the governing design are also important here. All groupings can be used for an isotropic material as well as for a governing shear force design.

Keywords

Dlubal FAQ Smoothing Grouped Averaging Frequently Asked Question FAQ about Dlubal Question and Answer about Dlubal

Links

Write Comment...

Write Comment...

  • Views 154x
  • Updated 01/05/2021

Contact us

Do you have any questions about our products or need advice on selecting the products needed for your projects?
Contact us via our free e-mail, chat, or forum support or find various suggested solutions and useful tips on our FAQ page.

(267) 702-2815

info-us@dlubal.com

CSA S16:19 Steel Design in RFEM

CSA S16:19 Steel Design in RFEM

Webinar 03/10/2021 2:00 PM - 3:00 PM EST

Online Training | English

Eurocode 5 | Timber structures according to EN 1995-1-1

Online Training 03/17/2021 8:30 AM - 12:30 PM CET

Online Training | English

Eurocode 3 | Steel structures according to DIN EN 1993-1-1

Online Training 03/18/2021 8:30 AM - 12:30 PM CET

Online Training | English

RFEM | Dynamics | USA

Online Training 03/23/2021 1:00 PM - 4:00 PM EST

Plate and Shell Buckling Utilizing Dlubal Software

Plate and Shell Buckling Utilizing Dlubal Software

Webinar 03/30/2021 2:00 PM - 2:45 PM

Online Training | English

RFEM for Students | USA

Online Training 04/21/2021 1:00 PM - 4:00 PM EST

Online Training | English

RFEM | Timber | USA

Online Training 05/05/2021 1:00 PM - 4:00 PM EST

Online Training | English

Eurocode 3 | Steel structures according to DIN EN 1993-1-1

Online Training 05/06/2021 8:30 AM - 12:30 PM

Online Training | English

Eurocode 2 | Concrete structures according to DIN EN 1992-1-1

Online Training 05/11/2021 8:30 AM - 12:30 PM

Online Training | English

Eurocode 5 | Timber structures according to DIN EN 1995-1-1

Online Training 05/20/2021 8:30 AM - 12:30 PM

Online Training | English

RFEM | Basics | USA

Online Training 06/17/2021 9:00 AM - 1:00 PM EST

The Most Common User Errors With RFEM and RSTAB

The Most Common User Errors With RFEM and RSTAB

Webinar 02/04/2021 2:00 PM - 3:00 PM CET

ADM 2020 Member Design in RFEM

ADM 2020 Member Design in RFEM

Webinar 01/19/2021 2:00 PM - 3:00 PM EST

Dlubal Info Day

Dlubal Info Day Online | December 15, 2020

Webinar 12/15/2020 9:00 AM - 4:00 PM CET

FEA Troubleshooting and Optimization in RFEM

FEA Troubleshooting and Optimization in RFEM

Webinar 11/11/2020 2:00 PM - 3:00 PM EST

Soil-Structure Interaction in RFEM

Soil-Structure Interaction in RFEM

Webinar 10/27/2020 2:00 PM - 2:45 PM CET

NBC 2015 Modal Response Spectrum Analysis in RFEM

NBC 2015 Modal Response Spectrum Analysis in RFEM

Webinar 09/30/2020 2:00 PM - 3:00 PM EST

Documenting Results in the RFEM Printout Report

Webinar 08/25/2020 2:00 PM - 2:45 PM

ACI 318-19 Concrete Design in RFEM

ACI 318-19 Concrete Design in RFEM

Webinar 08/20/2020 2:00 PM - 3:00 PM EST

How to Be More Productive Using RFEM

How to Be More Productive Using RFEM

Webinar 07/07/2020 3:00 PM - 4:00 PM

Introduction to Solid Modeling \n in RFEM

Introduction to Solid Modeling in RFEM

Webinar 06/30/2020 2:00 PM - 3:00 PM EST

Modeling with Solids in RFEM

Modeling with Solids in RFEM

Webinar 06/09/2020 3:00 PM - 3:45 PM