experimental considerations in the measurement of thermal relaxation and recovery of strained seals...

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