Quality Feel (Static) Analysis

Use SnRD to identify Squeak and Rattle for Static load.

In various industries, the perceived quality is measured by the touch and feel of the product. While being a subjective topic, the engineering community has broken down this assessment to different load cases. One of them is the Quality feel, which consists of applying a static force on different locations on the product, simulating a consumer touching/pressing the parts. The first assessment is to measure the stiffness [N/mm] and compare it to the target. While the stiffness can be acceptable, squeak issues can occur. These are the result of stick-slip between parts touching each other. With the SnRD Static loadcase setup and the associated post-processing capabilities, analysts can evaluate Squeak and Rattle under static loads.
Below is an illustration of the workflow that shall be covered in this usecase:
Figure 1.
Objective
  • Prepare the FE model for analyzing Squeak and Rattle issues.
  • Apply a static load of amplitude -5.55 to the certain node(s) on Lower Control Panel component. This simulates a touch point scenario.
  • Run analysis and post-process the results.
Starting Point

Choose the workflow according to your need and refer to sections mentioned above for the procedures. Once you have a model with E-Lines, you can proceed with the Static Loadcase Setup process.

Files Required

Files required to complete the usecase.

SnRD has packaged ...\hwdesktop\demos\snr\004_model_with_elines folder containing model and E-Lines pre-output CSV file:
Model File
tutorial_ip_snr_model.fem
E-Line Database File
tutorial_ip_snr_model_pre_output.csv

Step 4: Static Event Definition and Export

Create a Static event and constraints at the prescribed node(s), and export the solver deck.

Define Static Loadcase

Below are the steps to create a Static loadcase.

  1. From Setup group, select drop down arrow next to Dynamic > Static Event.
    Figure 2.
  2. From the graphics area, select the below listed node(s) on Lower Control Panel component.
    • 493552
    • 493543
    • 493563
    • 493478
    • 493477
    • 493518
    • 493503
    • 493494
    • 493530
    Figure 3.
  3. In the microdialog, select F, enter -5.55 as the amplitude and select X as the load direction.
    Figure 4.
  4. Click .
    This creates the Force loads at the selected nodes. The respective load collectors are created and listed in the model browser.

Define Constraint

Below are the steps to define model constraints.
  1. In the Setup ribbon, select Static Event > Setup Constraints.
    Figure 5.
    A guide bar will appear.
  2. From the graphics area, select the node shown in the below image.
    Figure 6.
  3. In the microdialog, select SnRD_STATIC_FORCE_1_X for the Loadstep option.
  4. Select all degrees of freedom.
    Figure 7.
  5. Click .
    This creates the Static loadcase with the load collectors and other entities required for the simulation. Respective load collectors get created and are assigned to the loadstep.

Export OptiStruct Solver File

  1. From Analyze group, select Export OptiStruct Solver File.
    Figure 8.
  2. Model Export window will appear.
    Figure 9.
  3. Click Export.
    A folder selection window will appear.
  4. Browse and select the required folder.
    This will export the OptiStruct solver deck file to the selected folder. Click Close to close the model export option.
Use the exported .FEM solver deck to solve on OptiStruct solver. Once done, two output files are generated: .H3D and .PCH. These files will be used in the Post Processing of results.

Step 5: Post Process results

Results post processing.

Import model and results file

Use the SnRD Post to post process the results.

Launch HyperWorks X, switch to HyperView client. Select File > Load > Preferences File. Preferences window will appear. Select Squeak & Rattle and click Load. This creates SnRD menu in the HyperView window.

  1. Select SnRD > SnRD-Post.
    SnRD Post Processing tool is launched.
    Figure 10.
  2. Using the file browse option , select the OptiStruct solver file which was exported in Step 4 for Model File.
    Note: Pre output CSV file containing the E-Lines definition is sourced automatically.
  3. Click .
    A file browser window will appear. Select tutorial_ip_snr_model.h3d from tutorials folder.
    A working status window will appear while reading the H3D data.
  4. Check the box against the subcase in Subcase selection table.
  5. Click in the Save Session File entry field.
    Browse and select the required folder where the post processing session and data will be stored.
    Once done, your entries in the tab should be as below-
    Figure 11.

Post Process

Perform Full Analysis to understand the Squeak and Rattle risks in the model.

  1. In the Post Processing tab, define the following-
    Analysis Type
    Rattle & Squeak
    Line(s) to Evaluate
    All
    % statistical evaluation
    0
    Session Type
    Full Analysis
  2. Click Execute.
    A working window will appear stating the Compose batch execution.
    Figure 12.
    Note: Execution of Full Analysis will take considerable time to chart histograms and plot contours based on the machine's performance.
    Execution success message will appear once done. Click Close to close the window.
    Figure 13.
Full analysis creates 11 pages containing all the details. The summary for Rattle analysis is placed in Page 1.
Figure 14. Rattle Summary Linear
Summary for Squeak analysis is placed in Page 8.
Figure 15. Squeak Summary Linear

From the results, you can observe that there are no Squeak and Rattle issues in the model for the applied static force. You can verify the issues by increasing the force amplitude and re-run the post processing.