The composite loss factor of reinforced thermoplastic molding compounds as a function of resonant vibration frequency, fiber orientation, and temperature

Abstract

The resonant‐vibration loss factor of composite molding materials is strongly influenced by the reinforcement fiber properties, the fiber orientation, the fiber:resin interphase, and the thermoplastic resin itself. Three commercially available thermoplastics were molded into plates and the plates then cut into high‐aspect ratio beams at precise angles off of the 0° machine direction. The loss factor was calculated by the half‐power bandwidth method from the resonant peaks to 3000 Hz, the beams being driven in resonance by a noncontacting magnetic probe. The beam data were collected at equilibrium conditions from − 50 °C to the softening point of the thermoplastic. The loss factor transitions observed as a function of temperature suggest that the resin choice, fiber choice, fiber orientation, and the manufacturing process optimization should be carried out on a composite structural design planned for acoustic applications prior to the consideration of active control of sound and vibration.