RF-/DYNAM Pro - Natural Vibrations | Features

  • Automatic consideration of masses from self-weight
  • Direct import of masses from load cases or load combinations
  • Optional definition of additional masses (nodal, linear, surface masses, as well as inertia masses)
  • Combination of masses in different mass cases and mass combinations
  • Preset combination coefficients according to EC 8
  • Optional import of normal force distributions (in order to consider prestress, for example)
  • Stiffness modification (for example, deactivated members or stiffnesses can be imported from RF-/CONCRETE)
  • Consideration of failed supports or members
  • Definition of several natural vibration cases (for example, to analyze different masses or stiffness modifications)
  • Results of eigenvalue, angular frequency, natural frequency, and period
  • Determination of mode shapes and masses in nodes or FE mesh points
  • Results of modal masses, effective modal masses, and modal mass factors
  • Visualization and animation of mode shapes
  • Various scaling options for mode shapes
  • Documentation of numerical and graphical results in the printout report

RF-/DYNAM Pro - Natural Vibrations | Input

Input windows require all data necessary for determination of natural frequencies, such as mass shapes and eigenvalue solvers.

The RF-/DYNAM Pro - Natural Vibrations add-on module determines the lowest eigenvalues of the structure. The number of eigenvalues can be adjusted. Masses are directly imported from load cases or load combinations (with optional consideration of total masses or a load component in the direction of gravity).

Additional masses can be defined manually at nodes, lines, members, or surfaces. Furthermore, it is possible to control the stiffness matrix by importing normal forces or stiffness modifications of a load case or combination.

RF-/DYNAM Pro - Natural Vibrations | Calculation

The RF-DYNAM Pro - Natural Vibrations module of RFEM provides four powerful eigenvalue solvers:*Root of characteristic polynomial

  • Method by Lanczos
  • Subspace Iteration
  • ICG iteration method (Incomplete Conjugate Gradient)

The DYNAM Pro - Natural Vibrations module for RSTAB provides two eigenvalue solvers:

  • Subspace Iteration
  • Shifted inverse power method

The selection of the eigenvalue solver depends primarily on the size of the model.

RF-/DYNAM Pro - Natural Vibrations | Results

After the calculation, the eigenvalues, natural frequencies, and natural periods are listed. These result windows are integrated in the main program RFEM/RSTAB. The mode shapes of the structure are included in tables and can be displayed graphically or as an animation.

All result tables and graphics are part of the RFEM/RSTAB printout report. This way, clearly arranged documentation is ensured. Furthermore, it is possible to export the tables to MS Excel.