PHENOMENOLOGICAL BASES OF AIRTIGHTNESS OF REINFORCED POLYMERS,
Abstract
A study was made of the relationship between the loss of airtightness and cohesion-adhesion binder fatigue. This condition originates in the orientation layers perpendicular to the reinforced layers at points of maximum density. Crack formation is discussed. The effect of binder adhesion on crack formation and propagation is studied. Monodirectional oriented polymers are most resistant to stress concentration. Likewise, thick-layered structures should be more airtight, since transfer layers are loaded by longitudinal layers. When the middle layers are lightly loaded, the thickness of the layer permits shear without disturbing the continuity of the binder. Shearing is due to redistribution of stresses between the layers of longitudinal reinforcement which increases the crack resistance of the material as well as its airtightness. Higher crack resistance increases the elastic potential of the material so that a large amount of elastic energy is released during formation of a critical crack. This energy overloads the longitudinal reinforcing fibers, resulting finally in brittle fracture. Thus it may be seen that thick-layer structures are actually weaker than those with thin layers. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 24, 1969
- Accession Number
- AD0703164
Entities
People
- O. G. Tsyplakov
Organizations
- National Air and Space Intelligence Center