6. Durability

An essential point to consider when designing composite enclosures is their durability. Several factors can reduce the service life of these structures, for example:

• creep (static fatigue) ;

• dynamic (i.e. cyclic) fatigue ;

• SHOCK;

• aging.

Creep (or static fatigue) is the viscoelastic deformation of a polymer under constant load. Numerous studies have been carried out on the behavior of composite tubes under internal pressure [1] [40] [41], but few data are available under external pressure. It is rare to be able to use hyperbaric chambers for long enough to carry out creep tests. However, under hydrostatic pressure, the dimensions of an enclosure will change, and this creep can lead to early buckling. Figure...