Romax Simulation of FRO-16210C Noise

1. CAViDS Consortium Romax Noise Simulation Romax Simulation of FRO-16210C Noise A CAViDS Consortium Project Eaton Discussion September 13, 2010

2. CAViDS Consortium Romax Noise Simulation Very Limited Objectives • Correlate 6th gear vibration • 500 to 2600 rpm • 500 LB-FT • First harmonic of first gear mesh • Accelerometer location 2 (front driver’s side). • This includes excitation of critical (and hopefully easy to predict) countershaft bounce and rock modes over speed range 1000 – 2200 rpm.

3. CAViDS Consortium Romax Noise Simulation Latest Status • Model includes imported CS gears (drive through 2nd) and MS 1st, second order housings, and simple dyno. CAViDS model approved by Romax. • Correlated free housing, countershafts, input shaft, main shaft and output shaft with ANSYS and experiment where applicable. Correlation considered good enough by Romax to proceed. • Prior to adding detailed first gear, bounce and rock modes showed consistently low in frequency but agreed in mode shape. Was ready to tune bearings. • After adding detailed first gear and re-condensing, bounce mode fell way off in frequency and changed in mode shape. Second attempt at dynamic analysis wouldn’t compute. No communication from Romax since.

4. CAViDS Consortium Romax Noise Simulation Existing Model without Housing and Dyno

5. CAViDS Consortium Romax Noise Simulation Existing Model with Housing and Dyno

6. CAViDS Consortium Romax Noise Simulation Best Correlation Rock Mode Bounce Mode

7. Romax Noise Simulation CAViDS Consortium History • Built whole gear/shaft/bearing model with Romax elements • Stripped out gears for each ratio and built separate models for each • Predicted key shaft modes. Looked reasonable • Added NASTRAN housing to each model • Predicted accelerometer response at three locations on housing for each model • Predicted effect of gear profile on vibration for each model • Compared with Kevin’s data in 6th gear. Found problem with bounce mode (no response in prediction where experimental peaked. Although mode was there it had no amplitude.) • Many attempts at better correlation, including adding dyno, tweaking model, improving bearings.

8. CAViDS Consortium Romax Noise Simulation Original Correlation Rock Mode Bounce Mode

9. Romax Noise Simulation CAViDS Consortium History • Did free housing experimental structural response, modeled in ANSYS, and improved NASTRAN housing model (Second order). No effect on correlation. • Did free countershaft experimental structural response, modeled in ANSYS, tried many Romax standard approaches without attaining free correlation. • Contracted Romax India. • Imported FE CS gears. Correlated to free CS experimental and ANSYS well enough. There was an unresolved discrepancy in Romax and CAViDS mode shapes (gear modes) • Checked correlation between Romax and ANSYS free modes for input shaft, main shaft and output shaft. Good bending agreement. Not good torsional. Romax claimed restraint issues so we moved on.

10. Romax Noise Simulation CAViDS Consortium History • Reassembled 6th gear model with FE gears. Dynamic analysis the same. • Added dyno. Dynamic analysis as shown in previous slide. • Changed to detailed 1st gear, re-condensed and changed correlation and stability of model. • Meanwhile Romax has built model which they have not shared with us as yet. This is promised soon.

11. Romax Noise Simulation CAViDS Consortium Romax Assessment • Strengths • Ease of Modeling • Graphics • Modal Visualization/Animation • Gear Geometry Modeling Flexibility/Power • Lessons Learned/Challenges • Prefers NASTRAN FE Housing Importation • Data manipulation for correlation is time consuming • Link to COUSTYX does not exist yet • Some conventions and even basic approaches not well communicated or documented • High level technical support is tough to get • Did not look at basic issues, resorted to rote approach • Communications difficult with India • Responsiveness lacking in India • No high priority in teaching