#720X - Bearings, Rotor Dynamics and Vibration Analysis

Course Objective

Upon completion of this course, participants will have gained a thorough understanding of the design, application and reliability evaluation of bearings in rotating machinery applications. They will also learn about rotor dynamics and vibration analysis as it relates to machinery condition monitoring systems.

Who Should Attend

This course is intended for both engineers without previous experience with bearing systems, and as a refresher for experienced engineers with rotating machinery responsibilities. The information discussed is also valuable for engineers, technologists, and other operational personnel who have machinery vibration analysis responsibilities. Specific applications and case histories will be discussed as the relevant topic is presented.

Course Description

This course is divided into the main sections as described below. 

Day 1 - Bearings

BASICS OF BEARING SYSTEMS

• Functions of Bearings
• Typical bearing systems in compressors
• Typical bearing systems in gas turbines
• The main types of bearings and their differences
  • Sleeve bearings
  • Ball bearings
  • Roller bearings

BEARING COMPONENTS

• Individual components in bearing systems in relation to the working fluid
• Loads and forces in bearings
• Lubrication systems for different applications
• Different geometries for varying applications
• Lubricant temperature/viscosity dependent properties and temperature effects
• Terms and definitions of hydrodynamic lubrication
• Terms and definitions of hydrostatic-hybrid lubrication
• Turbomachinery bearing types, performance and dynamic characteristics
• Oil whip
• Bearing and oil system maintenance & monitoring

Day 2 - Bearings (cont'd)

This day provides students with a better comprehension of the design, application and life potential of all bearings in contemporary turbomachinery. Practical examples and case histories will be discussed.

BEARING TYPES

• Ball bearings, angular contact and deep groove
• Roller bearings, cylindrical, spherical, needle and tapered
• ANSI/AFBMA/ISO, ABEC & RBEC, Metric v. Inch

MANUFACTURING TOLERANCES AND INTERNAL CLEARANCES

• Precision classes
• Clearances, mounting, operating

FAILURE MODES

• Surface and subsurface
• True & false brinelling
• Misalignment, roller edge stress

BEARING STRESSES AND FATIGUE LIFE

• Contact Stress
• Subsurface stress
• Static loads
• Dynamic capacity, static capacity
• Load rating
• Life assessment

LUBRICATION AND BEARING KINEMATICS

Elastohydrodynamic (EHD) lubrication, film thickness, low-speed vs. high-speed, skidding, time transients

MATERIALS AND PROCESSING

• Bearing materials - through-hardened steels, corrosion resistant steels, nonferrous materials (ceramic & ceramic hybrid bearings)
• Commercial vs. large diameter or custom bearings

MULTI BEARING SYSTEMS

Fixed bearings, floating bearings, service factors for each bearing posistion

Day 3 - Rotor Dynamics and Vibration

On this day, the basics of vibration analysis will be discussed. Bearing peformance is primarily monitored by vibration analysis and temperature analysis, both of which may be integrated into a machinery train's condition monitoring system.

• Introductory definitions including wave form, amplitude, frequency, total signal, filtered signal, phase angle, natural frequency, resonance, attenuation, damping, pulsation and surge
• Types of vibration sensors
  • Different sensors and their application
  • Displacement sensors/probes
  • Velocity sensors/probes
  • Accelerometers
  • Conversion of vibration measurement units for different systems
• Recorders and parameters for measuring vibration
  • Different sensors/probes (displacement, velocity, acceleration)
  • Vibration spectrum analyzer
  • Spectrum cascade
  • Phase angle measurement (Bode, Nyquist plots)
  • Orbital motion
• Monitoring systems (measurement equipment), scope and selection of monitoring systems: An Overview

Day 4 - Vibration Analysis

• Recommended vibration limits for different turbomachinery types and applications
• Troubleshooting
• Introduction to the Mechanics of Unbalanced Rotors, Introduction to Instrumentation and Equipment
• Introduction to Multiplane Balancing

Day 5 - Vibration Analysis and Other Aspects of Engine Condition Monitoring Systems

• Basics of Shop Balancing, Basics of Balancing Rigidly and Flexibly Coupled Rotors in the field
• Temperature Monitoring, Fuel Topping Systems, Temperature Monitoring Methods
• Pressure Monitoring

Course Duration - 5 days