Southwest Research Institute® (SwRI®) has the expertise and facilities to analyze, test, and evaluate rolling element bearings in turbines, aircraft, ground support equipment, and machinery.

Using a wide range of analysis methods, SwRI engineers predict the parameters controlling bearing life from the specified service conditions. These analytical methods, benchmarked by physical testing, include:

• Finite element programs to estimate mechanical loads and stresses
• Finite element and finite difference programs to evaluate transfer of heat and fluid to and from the bearings
• Dynamics programs to predict the gyroscopic forces acting on the bearings
• Solid modeling programs to evaluate bearing fit

Rolling element bearings are an integral part of flight critical and other aerospace equipment including motors and gimbals in avionics, aircraft turbines, support machinery, and ordnance. Shown is an assessment of bearing damage using noise characteristics.

SwRI engineers routinely analyze bearing performance in laboratory simulations and equipment operations.

Bearings diminish friction and improve efficiency, but a bearing failure may cause catastrophic destruction. Shown is a damaged bearing race.

To simulate bearing operating environments, engineers use SwRI's extensive environmental test facilities and laboratories including:

• Environmental chambers
• Altitude chambers
• Shakers

If required, SwRI engineers evaluate bearings at offsite facilities during operation in the equipment. In addition to standard measurement and data analysis procedures, field investigators adapt unique measurement and analysis techniques to investigate rolling element bearing problems in rotating machinery.

A. The reliability of the Aircraft Mounted Accessory Drive and the associated systems installed in the T-38 has been tested for over 1,000 hours of simulated operation.	B. Re-engineered test stand used to evaluate the performance of the Aircraft Mounted Accessory Drive and related assemblies.	C. Durability tests conducted on the input coupling attached to the Aircraft Mounted Accessory Drive.

The root cause of bearing failures is investigated through analysis, measurement of performance, or testing under simulated loading in the laboratory. Cause of failure and recommended corrective action, such as change lubricants, retolerancing, alternate replacement bearings, and improved lubrication, are determined through a synergistic combination of methods including:

• Metallurgy
• Mechanics
• Tribology
• Acoustics

SwRI analyzes aircraft, aircraft accessories, ground support equipment, and machinery to identify the root causes of bearing failure and recommend corrective actions. The SwRI analysis may include the use of tribology, metrology, classical mechanics methods, finite element modeling, materials investigations, heat transfer studies, and other techniques in a multidisciplinary approach to solving the problem.

SwRI investigators perform field studies to measure, evaluate, and solve performance problems related to rotating element bearings. Dynamic data from specially installed instrumentation and data acquisition equipment is interpreted to provide cost-effective solutions to abnormal machine operations. This data may be transmitted in real time from remote field locations directly to engineers for analysis.

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