Problem 11: Dynamic Analysis for Vibration of an Unbalanced Mass
Objective
A 65 Kg industrial sewing machine has a rotating unbalanced mass of 0.15 Kg-m. The machine operates at 125 Hz and is mounted on a foundation of equivalent stiffness 2x106 N/m and damping ratio 0.12. What is the machine's steady state amplitude?
Figure 1.
Entities Validated
- Rigid body
- Revolute joint
- Translational joint
- Force_Spring damper – translational
Type of Analysis
- Dynamic
Reference
Schaum’s Outline of, Theory and Problem of Mechanical Vibrations, First Edition by S Graham Kelly: 82 (ISBN 0-07-034041-2)
Model Files
- rotating_unbalance_mass.mdl - MotionView Model
- rotating_unbalance_mass.xml - MotionSolve Deck
Graphical Results
Figure 2.
Result Comparison
| Output | Analytical | MotionSolve | % Error |
|---|---|---|---|
| Steady state amplitude of machine (mm) | 2.43 | 2.43 | 0 % |
Conclusion
MotionSolve results compare well with analytical results.