Songping Liu

Measuring Sound Velocities and Anisotropy of Microstructural Units of Laminate Composite Materials by Microacoustical Technique

The CFR composites are manufactured as laminate packages of ordered carbon fiber layers (prepreg plies) embedded into a polymer binder (epoxy, bismeleimide or other types of polymer resin). Elastic properties of these primary elements of the laminate structure differ dramatically. Carbon fibers are characterized by high values of elastic moduli; the maximal magnitude is taken by the tensile modulus Et~ 230÷900 GPa [1]. Elastic moduli of the resin binder are significant smaller; they are close to characteristics of solid polymers (5 ÷ 20 GPa). Elastic properties of the CFR composite materials depend on a type and density of fiber bundle arrangement in a ply, as well as on structure of macroscopic ply stacking. Ultrasonic techniques are widely employed for studying mechanical properties and non-destructive evaluating of carbon fiber reinforced (CFR) laminates [2—5].