ABSTRACT
This chapter discusses the connection between the several load-dependent regression equations. The damage path originates at the same pristine state and evolves in the same way passing through all damage states corresponding to the four modes of failure. The infiltration state of damage, followed by the weeping and stiffness states until the ultimate damage state corresponding to rupture. The practical approach to such cases consists in interpolating between known regression lines. The interpolation is possible for the time-independent modes of failure such as infiltration, weeping, and stiffness. The accumulated damage from such a long-duration load is very large and the ply residual strengths reduce to extremely low values. The residual strength at the point of convergence is the fatigue threshold of the ply. The state of damage of the ply at the long-term fatigue threshold is so high as to obliterate the difference in resin toughness.
