4. Glossary

permeation; permeation

Phenomenon corresponding to the passage of a gas through a wall (solid material) resulting from a solution-diffusion mechanism.

creep

A phenomenon that can be observed when the application of a constant stress results in a progressive increase in deformation.

relaxation; relaxation

Phenomenon that can be observed when the application of a constant strain results in a progressive decrease in stress.

elasticity

Property of a material to return to its original shape (identical load-unload path) after being subjected to a mechanical load (small deformation). The linear relationship between stress and strain is known as Hooke's Law (where E is Young's modulus).

plasticity...