Measuring elastic properties and anisotropy of microstructural units of laminate composite materials by microacoustical technique

The paper is devoted to application of focused ultrasonic beams for measuring bulk elastic properties in advanced fiber composite materials, such as carbon fiber-reinforced composite (CFRC) laminates. Long-focus convergent beam of 50 MHz ultrasound frequencies provides the exceptional means of measuring elastic properties of microstructural units in composite materials with intricate microstructure as well as their integral properties. The microacoustical measurements reveal high anisotropy of CFR-laminate layers: sonic velocity across plies was found to be equal 3.1 km/s; in ply plane across fiber packing—7.0 km/s and along fibers—9.0–9.8 km/s.