ug振动响应分析详细分析教程

HESSI Satellite

Assembly FEM/Response Simulation Workshop

In the last workshop, you built the satellite in the deployed configuration. For the launch loads applied with in this workshop we need the satellite in the deployed configuration.

Since this would be a repeat of steps that you had done, this was done for you using the following steps:

ed the solid properties and calculated the mass

of a panel.

2.Unmapped the panels from the assembly FEM.

3.Added 3 concentrated masses at the connection

points for the solar panels.

Steps of this Workshop:

1.Apply Enforced Displacement Restraints

2.Create the global damping

3.Solve for the normal modes

4.Create a response simulation

5.Review the results for the mass participation

6.Create the sensors

7.Create a random excitation

8.Calculate the acceleration at the sensors

9.Calculate the RMS for the middle platform

PART II: Response Simulation

Open and load necessary files

Select “File, open” to open “satellite_sim1.sim” file.

•Set ‘Files of type’ to “Simulation Files (*.sim)”

•Navigate to the appropriate folder and select “satellite.sim”

•Select OK

In the simulation navigator, create a new solution. Solution type is Sol 103 Response Simulation.

Make sure to move all the contact sets to the new solution.

Create the restraints and enforced motion locations

Select the “No Rotation” icon and the center node of the rigid element on the base of the satellite.

Select the “Enforced Motion Location” icon, and select the same node. Assign the 3 translational DOF to the motion.

Save your work.

Set up Normal Modes Solution

Highlight the Dynamic Subcase, and use the RMB to select “Edit Solution Step”.

Create an output request for Displacement and Stress. Then create a Lanczos solve for 100 modes between 0 and 500 HZ.

Highlight the solution and use RMB to select “Edit Solution”. Select the Parameters tab, and set the “AutoMPC” to “Yes” and the “G” to 0.04. G sets the global damping. (Note: G is 2 times the ratio C/C0)

Save your work.

Review Normal Modes

Switch to Post-Processing and load the results. The first mode should be around 44 HZ.

Return to the simulation navigator. Highlight the SIM and using RMB, select “New Solution Process” and ‘Response Simulation”.

Select OK when the form comes up. This allows the user to select the desired solution if more then one normal modes analysis has been done.

In the simulation navigator, highlight the normal modes. Open the Response Simulation Details View and review the total percent of mass participating using the 100 modes. This typically should be between 80% and 85%.

Save your work.