1. Case Study: Bearing Defect in a Paper Mill Drying Cylinder
Unusual noise, high temperature, or a spike in overall vibration levels.
The FEA simulation revealed multiple natural frequency issues that combined structural and rotordynamic resonance. By providing detailed vibration data alongside FEA modelling results, the case study demonstrates a methodology for solving complex resonance issues in pump systems.
"It is not unbalance, Silas," Leo yelled back. "Look at the phase analysis. The motor and the pump are out of step. We have a severe angular misalignment." Practical Case Studies On Vibration Analysis Pdf
Analysts used High-Frequency Enveloping (HFE) . While the standard velocity spectrum looked clean, the enveloped spectrum revealed distinct peaks at the Inner Race Ball Pass Frequency (BPFI) .
To successfully deploy vibration analysis based on these practical cases, engineering teams should follow a standardized implementation workflow:
Two hours later, after correcting the soft foot and realigning the coupling, they flipped the starter switch. The motor whirred to life. Leo placed his hand on the casing. It was as smooth as glass. By providing detailed vibration data alongside FEA modelling
System-wide recurrent low-frequency signatures were identified, with peaks repeatedly appearing around 14.5 Hz, 16 Hz, and 37.8 Hz across multiple locations, indicating strong structural coupling and vibration transmission. The cumulative-stabilisation view exposed critical anisotropy at the workpiece table, with the Oy direction exhibiting the largest accumulated vibration burden and a markedly slow stabilisation of approximately 313 seconds.
For decades, vibrations were viewed as little more than an unpleasant side effect of mechanical motion—a byproduct to be endured rather than studied. However, over the past thirty years, vibration analysis has evolved into one of the most powerful diagnostic tools in industrial engineering. By examining vibration signatures, engineers can now peer into the inner workings of rotating machinery and detect impending failures long before they manifest as audible noise or operational disruptions.
), with sidebands around it equal to the pole pass frequency ( The motor and the pump are out of step
Based on the practical applications reviewed, the following core lessons were identified:
The presence of BPFI frequencies with running speed sidebands confirmed on the inner ring of the drive-end rolling-element bearing.
They welded structural steel gussets to the motor support frame to stiffen the assembly. This stiffening shifted the structural natural frequency from 59.2 Hz up to 74 Hz, well away from any operational excitation forces.