Ultrasonic assembly of short fibre reinforced composites

Taking a counter-propagating wave approach, a new type of device was developed to fabricate thin layers of anisotropic material. To investigate the effects of various design parameters, enhance device performance, and improve the composite fabrication process, finite element (FE) analysis was employed. Specifically, the COMSOL Multiphysics package was used to couple together the equations of structural mechanics, piezo-electric devices, and pressure acoustics in a single model. Special attention was paid to the shape and quality of the acoustic standing wave field, the magnitude of the resulting radiation forces, and the response of fibrous particles to ultrasonic pressure gradients. Further, the formation of structurally interesting fibre architectures was explored by studying the possible standing wave patterns in the device's particle manipulation cavity.