Industrial composites |
Many materials today can be purpose-engineered to suit the task they will perform. For example, concrete can be reinforced with metal rods for tensile strength, or resin combined with carbon nanotubes to improve strength-to-weight ratios. Materials created in this way, from two or more parts, are known as composites and are widely used throughout industry.
One particular type of composite studied by our research group comprises microspheres embedded in a rubber-like host medium. The microsphere is a hollow thermoplastic spherical particle, a few microns in diameter, with a wall-thickness typically around 100nm. The use of microspheres in materials brings forth numerous benefits which include a lower density, improved stability, increased impact strength, a smoother surface finish, greater thermal insulation, a higher compressibility, and often a reduced cost [1].
The application of most interest to our group is that of acoustics, using microsphere composites as a means of reducing sound reflection. More specifically, we investigate how this sound reflection can be affected by pressure applied to the composite. Microsphere composites have been found to be useful under high pressure because the presence of shells reinforces the cavities, delaying cavity collapse and the consequent degradation in the acoustic performance of the composite. In order to understand exactly how the acoustic characteristics of the material are affected by pressure, we develop models that describe how the composite deforms mechanically under loading.
One of our PhD students, Maria Thorpe, is currently looking at how microspheres within the composite may interact and whether this will affect the pressure at which the shells of the microsphere buckle.
One particular type of composite studied by our research group comprises microspheres embedded in a rubber-like host medium. The microsphere is a hollow thermoplastic spherical particle, a few microns in diameter, with a wall-thickness typically around 100nm. The use of microspheres in materials brings forth numerous benefits which include a lower density, improved stability, increased impact strength, a smoother surface finish, greater thermal insulation, a higher compressibility, and often a reduced cost [1].
The application of most interest to our group is that of acoustics, using microsphere composites as a means of reducing sound reflection. More specifically, we investigate how this sound reflection can be affected by pressure applied to the composite. Microsphere composites have been found to be useful under high pressure because the presence of shells reinforces the cavities, delaying cavity collapse and the consequent degradation in the acoustic performance of the composite. In order to understand exactly how the acoustic characteristics of the material are affected by pressure, we develop models that describe how the composite deforms mechanically under loading.
One of our PhD students, Maria Thorpe, is currently looking at how microspheres within the composite may interact and whether this will affect the pressure at which the shells of the microsphere buckle.
- R De Pascalis, I David Abrahams, WJ Parnell. Predicting the pressure–volume curve of an elastic microsphere composite. Journal of the Mechanics and Physics of Solids 61 (4), 1106–1123.