Method Fabricating Load-Bearing Composites Free from Microbuckling Deformation Up to a Predetermined Load.
Patent application filed, 3 Jul 91,
DEPARTMENT OF THE NAVY WASHINGTON DC
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A method fabricating a continuous filament reinforced composite free from microbuckling deformation up to a predetermined load with a high degree of certainty is disclosed. A continuous filament is selected from among a group of appropriate types of filaments. A matrix material is selected from a group of appropriate types of matrix materials. Selected filaments are undirectionally embedded in the selected matrix to provide a uniaxially continuously reinforced composite. The Youngs modulus and the shear modulus are calculated for the composite. Mathematical formulas are provided for calculation of upper and lower bounds of transverse stiffness, B. A mathematical formula is provided for calculation of critical comprehensive stress, P sub c. Transverse stiffness, B, is involved as one of the factors in this formula. Either one or the other of the upper bound of B or the lower bound of B are alternatively applied in calculating P sub c depending upon a consideration related to the shape of a cross section of the structural member into which the composite is to be formed. A structural member subjected to load values below P sub c will be free from load-induced microbuckling with a high degree of certainty.
- Laminates and Composite Materials