Maneuver load analysis

Maneuver load analysis is a SOL 101 linear static structural analysis that accounts for inertial loads including gyroscopic forces. It is commonly performed in the aircraft industry, but is potentially applicable to any linear static structural problem where gyroscopic forces are present. Gyroscopic forces occur when the rigid-body motion of the model causes the axis of rotation of rotors in the model to change. To account for gyroscopic forces in a maneuver load analysis, you must use Simcenter Nastran as the solver.

Besides gyroscopic forces, in a maneuver load analysis you can also account for the centrifugal forces that result from the rigid-body motion of the model, and the centrifugal forces that result from the motion of the rotors in the model.

The workflow for a maneuver load analysis is essentially identical to that for any other linear static analysis that includes inertial loads. However, to include gyroscopic forces in the maneuver load analysis, you must create a rotor dynamic simulation object. To create the rotor dynamic simulation object, use the Rotor Dynamics Definition command.

In the rotor dynamic simulation object, you can:

• Define the rotors.

• Map CBEAR elements to the rotors.

• Define stationary nodes for the CBEAR elements.

• Specify system-wide and rotor-specific rotor dynamic solution options.Note: The rotor speeds that the software uses during the maneuver load analysis are the product of the starting rotor speed and the speed multiplier for each rotor. You specify the starting rotor speed in the system-wide rotor dynamic solution options. You specify the speed multipliers in the rotor-specific solution options. If you also specify values for step size and number of steps in the system-wide rotor dynamic solution options, they are ignored.

You specify the rigid-body motion of the model with the Acceleration and Rotation commands.

• Use the Acceleration command to specify the linear acceleration.

• Use the Rotation command to specify the angular velocity and angular acceleration.

For example, suppose you perform a maneuver load analysis on an aircraft with wing-mounted gas turbine engines. You specify the operating speed of the engines with the Rotor Dynamics Definition command. You specify the pitch, yaw, and roll conditions for the aircraft with the Rotation command. You specify the linear acceleration of the aircraft with the Acceleration command.

When you specify the Rotation command, you have the following options:

• To include the gyroscopic forces, the centrifugal forces that result from the rigid-body motion of the model, and the centrifugal forces that result from the motion of the rotors, from the Type list, select Whole Model for the software to calculate the loads for the entire model.The software writes an RFORCE bulk entry in the Simcenter Nastran input file.

• To include the gyroscopic forces, the centrifugal forces that result from the rigid-body motion of the model, and the centrifugal forces that result from the motion of the rotors, from the Type list, select Model Subset for the software to calculate the loads for a subset of the entire model.The software writes an RFORCE1 bulk entry in the Simcenter Nastran input file.

• To exclude either the gyroscopic forces or the centrifugal forces that result from the motion of the rotors, from the Type list, select Rotor Dynamics Whole Model. Then from the Calculation Option list, select Centrifugal Only or Gyroscopic Only. For the Centrifugal Only and Gyroscopic Only options, the software calculates the loads for the entire model.The software writes an RFORCE2 bulk entry in the Simcenter Nastran input file.

Centrifugal stiffening and softening, and mass imbalance are not supported in maneuver load analysis.

For information on how to create a rotor dynamic simulation object and how to define bearing supports for rotors, see Rotor dynamics.

Learn more

Maneuver load analysis with gyroscopic forces workflow

Quick links

Command reference

Pre/Post video examples

Bulk Entry Descriptions

Simcenter 3D tutorials

Browse Simcenter 3D help by product area

Maneuver load analysis, Simcenter 3D 2021.1 Series

© 2020 Siemens

window.mainLanguage="en_US"

window.delivId=""

window.projectId=""

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