15:00 Thursday 4th October 2018

SurFlow™ Data Transmission through Composite Sports Equipment

Composites are in widespread use in the sports industry as they can offer significant weight savings that lead to improved performance. The drive to be even more competitive is demanding ever more sophisticated data capture and analysis so that technique and equipment can be improved or tailored to suit individual competitors. Smart sensors for sport now include; strain, force, video & sound, accelerometers, proximity, damage, temperature, heart rate, respiration, rotation and eye movement. This requires sensors and wires to be attached to the athlete, or their equipment, which can often interfere with operation and make the data unreliable. Wireless (wi-fi) transmission is becoming popular, but is not secure; data can be expensive to acquire and teams may not wish their valuable data captured during training or practice at events to pass to competitors. TWI has developed an alternative in the form of surface wave data transmission using the composite structure itself as a data transmission conduit; a technology known as SurFlow™. Not only will this improve the speed and security of the data transmission but greatly reduce the complexity of the system, as well as allowing for high bandwidth transmission for future expansion. An electromagnetic surface wave (ESW) is a non-radiating mode that propagates along the interface between two dissimilar materials. This is an evanescent wave, meaning that it decays exponentially from the surface of the interface in the vicinity of which the propagating energy is localised. The excitation and propagation of ESWs are affected by the interface geometry and its surface impedance (Zs), which can be modified by altering the composite material construction. The skill in exploiting ESW for data transmission in composite structures is to balance these electromagnetic requirements with the structural performance requirements of the equipment.

Chris Worrall, TWI Ltd.