XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX''"> Set Up First Fatigue Analysis
By now you should know how to access the MSC Fatigue setup form and have a fairly good idea how to set up a basic fatigue analysis. Open the form and set the General Setup Parameters as follows to run a fatigue analysis on just the operating load case:
1. Analysis: Initiation
2. Results Loc.: Node
3. Nodal Ave.: Global
4. F.E. Results: Stress
5. Res. Units: PSI
6. Jobname: mold
7. Title: Crack Initiation Analysis of Injection Mold
Solution Parameters
Open the Solution Params... form. Nothing needs to be changed here. Simply accept all the defaults.
Material Information
Open the Material Info... form. Set the following on this form as done in previous exercises:
1. Material: SAE4340-350A_QT
2. Surface Finish: Polished
3. Surface Treatment: No Treatment
4. Region: default_group
Loading Information
Open the Loading Info... form. Then press the
Time History Manager button to launch PTIME and define a unit load with R=
. Use
X-Y time series with three points (
0, 1, 0) to define this simple load simulating a fill of the injection mold form zero load to the maximum and back to zero.
Note: | As mentioned in the previous chapters, if you have been working sequentially through this document, then you will need to select Add an entry before you can enter the X-Y point data. |
Call it FILL_LOAD. Give it the following details when asked:
1. Description 1: Constant Amplitude, R=infinity, Unit Load
2. Description 2: whatever you want
3. Load type: Pressure
4. Units: PSI
5. Fatigue equivalent units: Fills
Next fill out the Loading Info... form with the following input:
1. Load Case ID: 2.1-2.1-1-
This corresponds to the LS_PRESSURE_12.5KPSI result case which is the operating load only without any residual stress. Remember, the load case IDs may not match those shown here.
2. Time History: FILL_LOAD
3. Load Magnitude: 1.0
Run the Fatigue Analysis
You are ready to run the fatigue analysis. Open the Job Control... form, set the Action to Full Analysis and click the Apply button.
Review the Results
Open the Results... form on the main MSC Fatigue setup form and either read the results into the database and create a contour plot or use the tabular listing facility to find the node with the lowest life as has been done in previous analyses. You should find that the smallest life reported is approximately 67,000 Fills, which is far off from the design goal of 500,000 Fills.
