Experimental Considerations in the Measurement of Thermal Relaxation and Recovery of Strained Seals
Kurt Miller
Axel Products, Inc.
www.axelproducts.com
Available at: www.axelproducts.com.
Overview
• Elastomer Seals• Stress, Strain and Temperature• A Particular Experiment
Elastomer Seals
• Normally Compressed• Fill a Space• Provide a Reaction
Force• Survive Temperature
Changes• Survive Chemical
Attack
Stress, Strain and Temperature
• Mental Experiment• Actual Experiment
Stress, Strain and Temperature
Stress, Strain and Temperature
• Short Term Stress Relaxation
• Some Softening
Stress, Strain and Temperature
Stress, Strain and Temperature
• Thermal Expansion • Elastomer > Steel
• Thermal Softening• Thermal Degradation• Additional Crosslinking
Stress, Strain and Temperature• Thermal Expansion vs Thermal Softening
Stress, Strain and Temperature
• NOT Long Term Stress Relaxation
Stress, Strain and Temperature
Stress, Strain and Temperature
• Thermal Contraction• Reduced Reaction Force
Stress, Strain and Temperature
Stress, Strain and Temperature• Additional Thermal Contraction• Reduced or Possible Loss of Reaction Force• The Seal May go into Tension!
A Particular Experiment
A Particular Experiment
A Particular Experiment
• Example Data, Constrained Seal
A Particular Experiment
• Example Data, Constrained Seal
A Particular Experiment
• This does not replace aging experiments.
A Particular Experiment
• This does not replace aging experiments.
A Particular Experiment
• This does not replace:– Thermal Expansion by TMA– Compression Set
Overview• Bad Things Happen When Hot,
Become Evident When Cold• Experimental data is Helpful