User Guide

Tutorial 5 – Dynamic Analysis
Version 5.0 109
The dialog should look like the following figure:
Click and the dynamic solution begins.
The term “dynamic analysis” typically is taken to mean the analysis of a model
for dynamic loading, including the calculation of stresses and displacements. For
the purposes of RISA-3D, the analysis of a model for dynamic effects is
considered to be composed of two parts.
The first part is the actual “dynamic analysis” (what we're doing here), which
means the calculation of the modes and frequencies of vibration for the model.
The second part is the “response spectra analysis”, which uses these modes to
calculate forces, stresses and deflections in the model.
Once the dynamic analysis is complete, you'll find yourself at this spreadsheet:
Frequencies and Mode Shapes
These are the frequencies/periods calculated for the model. The last three
columns are the modal participation percentages, which will be filled in after we
perform the response spectra analysis.
You can also review the mode shapes graphically. Let's set up our screen a bit
differently to look at the mode shapes.
Click and then select Three Input Views. Now close the bottom and
right side views by clicking on the button in their titlebars and close the
Results toolbar by clicking it’s .