FAQ 004302 | Is it possible to perform a dynamic analysis of the initial deflection of a structural component in RFEM or RSTAB?

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Stine Mareike Effler

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Is it possible to perform a dynamic analysis of the initial deflection of a structural component in RFEM or RSTAB?


Yes, it is possible by using the RF‑/DYNAM Pro - Forced Vibrations add-on module. This application also allows you to use time history. It is available for both solution methods (linear Newmark analysis or modal analysis), but the procedures are slightly different.

The procedure is as follows:

  1. Define a load case containing a load that causes the desired initial deflection.
  2. Activate the time history method of time diagrams in RF‑/DYNAM Pro, and define a new time diagram that has a multiplier of 0 over the entire time.

    Figure 01 - Time Diagram with Multiplier 0

  3. Then, select the defined time diagram in the dynamic load cases (it is irrelevant which load case you combine it with as it multiplies the load by 0). You can then import the load case defined in the first step as the initial condition (or only the initial deformation in the modal analysis). Thus, the conditions from this load case are imported at time t = 0 and released immediately afterwards.

    Figure 02 - Activating Initial Condition/Deformation in Dynamic Load Cases

Use this procedure to simulate a vibration after the initial deflection. To illustrate this, you can find an example file under Downloads where this method is shown on a single-mass oscillator.


Dlubal FAQ Forced vibration Single-mass oscillator Initial deflection Initial deformation Frequently Asked Question FAQ about Dlubal Question and Answer about Dlubal


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  • Updated 08/19/2020

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