Advanced science.  Applied technology.


A Real-Time Metric for Mapping the Performance of Elastomer Seals under Dynamic Conditions, 08-R8731

Principal Investigators
Nigil Jeyashekar
Inclusive Dates 
01/01/17 to 01/08/18


Elastomer O-rings are used extensively for sealing applications in automotive and aviation system hardware components for both static and dynamic applications. Alternative jet fuels, which typically consist solely of paraffins and lack aromatic components, can cause leaks due to insufficient seal swell.

In dynamic sealing applications, the relative motion between the moving components causes elastomer wear leading to seal failure. Static soak tests do not simulate actual operating conditions.

SwRI has developed a methodology to map the dynamic performance of elastomer O-ring seals in real time and has built a dynamic seal tester to investigate the effect of alternative fuels on elastomer seals in a simulated turbojet engine environment.


The test rig consists of a heated test block under pressure containing a reciprocating shaft housing the test elastomer O-rings, simulating real-world dynamic motion in fuel-wetted components. Instruments measure the resistance to reciprocating motion experienced by the O-rings in real time. As the elastomer wears down due to the combination of fuel effects, temperature, and dynamic motion, the elastomer resistive force decreases.

Buna-N O-rings were tested with a 50/50 jet fuel-synthetic fuel blend and 100 percent synthetic fuel at 200˚ F with a reciprocating frequency of 0.2 Hz and a linear speed of 0.0075 in/sec.

The test with 50/50 JP8-FTSPK fuel blend ran for 400 hours with no fuel leakage, indicating no O-ring failure. The test with 100 percent alcohol-to-jet fuel showed significant wear and O-ring failure at 223.5 hours. Performance of elastomer fatigue, swell, wear, and failure mechanism was mapped, showing the variation in elastomer resistive force as a function of test time.


The theory of elastomer wear was shown to be correct and a dynamic fuel/lubricant seal compatibility tester has been developed and proven to work. It is able to predict failure in seals before static seal testers.

Presentation: Lee, P.M. and Jeyashekar, N. Mapping the Performance of Dynamic Elastomer Seals. STLE 73rd Annual Meeting and Exhibition, Minneapolis, USA, May 2018.

Patent Filed: June 30, 2017 for “Method and Apparatus for Mapping the Performance of Elastomer Seals under Dynamic Conditions”