Ultrasonic assembly of anisotropic short fibre reinforced composites

• Published in: Ultrasonics 2014-04, Vol.54 (4), p.1015-1019
• Main Authors: Scholz, M.-S., Drinkwater, B.W., Trask, R.S.
• Format: Article
• Language: English
• Subjects: Acoustic radiation pressure; Anisotropy; Assembly; Devices; Discontinuous fibre composites; Failure; Mechanical properties; Particle manipulation; Polymerization; Short fibres; Strands; Stress-strain relationships
• ISSN: 0041-624X; 1874-9968
• DOI: 10.1016/j.ultras.2013.12.001

•The successful manufacture of discontinuous fibre composites via ultrasonic assembly.•Structural anisotropy is clearly demonstrated.•Device allows the manufacture of thin layers of composite material.•Technique suitable for both photo-initiator and temperature controlled polymerisation.•Future applications include additive layer manufacture. We report the successful manufacture of short fibre reinforced polymer composites via the process of ultrasonic assembly. An ultrasonic device is developed allowing the manufacture of thin layers of anisotropic composite material. Strands of unidirectional reinforcement are, in response to the acoustic radiation force, shown to form inside various matrix media. The technique proves suitable for both photo-initiator and temperature controlled polymerisation mechanisms. A series of glass fibre reinforced composite samples constructed in this way are subjected to tensile loading and the stress–strain response is characterised. Structural anisotropy is clearly demonstrated, together with a 43% difference in failure stress between principal directions. The average stiffnesses of samples strained along the direction of fibre reinforcement and transversely across it were 17.66±0.63MPa and 16.36±0.48MPa, respectively.