Response Dynamics > Defining the Simcenter Nastran solution

Define the frequency range and number of modes to solve

You can limit the frequency range of the modes to solve and you can specify the number of modes to solve.

In the Simulation Navigator, right-click the Subcase - Dynamics node and choose Edit. Note: If you are using an SOL 103 Real Eigenvalues solution (rather than SOL 103 – Response Dynamics), you can edit the solution and click the Case Control tab.
In the Solution Step dialog box, make sure Real Eigenvalue Extraction Data is set to Lanczos (the Lanczos extraction method is best for most solutions; use the Householder method only if you understand its requirements). These steps assume that you choose the Lanczos method.
Click Create Modeling Object (next to Real Eigenvalue – Lanczos).
(Optional) In the Real Eigenvalue – Lanczos dialog box, type a minimum and maximum frequency in the Frequency Range – Lower Limit and Upper Limit boxes. This range limits the modes the solver generates according to the frequency of each mode. For example, if you specify a range from 1 Hz to 1000 Hz, the solver only generates modes within that range. Leave these range values blank if you do not want the modes to be limited by frequency range.
In the Number of Desired Modes box, type the number of modes to generate. Note: The Frequency Range and Number of Modes Desired values together determine the modes the solver generates. See Real Eigenvalue (Lanczos or Householder) dialog box for a table that lists the interaction between these values.
Click OK.
Close the Solution Step dialog box.

Define rigid-body mode tolerance for Simcenter Nastran

Define Response Dynamics result types

Filter out modes according to their modal effective mass fraction

Import results and event data from I-deas

Defining the Simcenter Nastran solution

Simulating unconstrained structures using Fictitious Support

Efficiency through restart analysis

Command reference

Pre/Post video examples

Bulk Entry Descriptions

Simcenter 3D tutorials

Browse Simcenter 3D help by product area

Define the frequency range and number of modes to solve, Simcenter 3D 2021.1 Series

window.mainLanguage="en_US"

window.delivId=""

window.projectId=""

MathJax.Hub.Config({ TeX: { extensions: ["autoload-all.js"] }, tex2jax: { displayMath: [ ] }, "SVG": { scale: 125 } });