Newell, B., Krutz, G., Harmeyer, K., and Holland, M., "Integrity Sensing with Smart Polymers and Rubber Components on Vehicles (i.e. Tires, Hoses, Seals)," SAE Technical Paper 2013-01-0742, 2013, doi:10.4271/2013-01-0742.
This research provides a capacitance based method for monitoring the integrity of tires and other polymeric products during manufacturing and throughout the useful product life. Tire and wheel failures and tire degradation were the reported cause for approximately 19320 vehicle crashes over a two and a half year period according to the U.S. Department of Transportation National Highway Traffic Safety Administration's 2008 survey. Tires are complex composite structures composed of layers of formulated cross-linked rubber, textiles, and steel reinforcement layers. Tire production requires precise manufacturing through chemical and mechanical methods to achieve secure attachment of all layers. Tires are subjected to a variety of harsh environments, experience heavy loads, intense wear, heat, and in many cases lack of maintenance. These conditions make tires extremely susceptible to damage. The sensor presented in this research utilizes the existing dielectric rubber and conductive steel belts within the tire to create a parallel plate capacitor which can detect the formation of gaps between layers due to a loss of cross-linking or environmental effects, cuts within a layer due to punctures or slicing, and decreased layer thickness due to overall wear. This system can alert the driver to tire problems before accidents occur increasing driver safety, improving quality control from the manufacturing site, and decreasing costs due to rim and frame damage and accidents caused by tire malfunctions. Overall, this research provides a mechanism for continuously monitoring tire stability and uses current tire materials for device construction. Similar technology on hoses, seals, and polymers has also been developed.