Aircraft Tire Contact Patch Force and Shear Sensor

Military aircraft tires must handle extreme loads during landing, take-off and taxi. New designs must be evaluated to determine if they meet mission capability requirements. A key evaluation area is the distribution of normal and shear forces in the tire contact patch. These data are critical for understanding tire performance, tire/landing gear interactions, and as inputs to tire wear and failure models. Current technologies suffer from issues such as providing only discrete measurements, providing only pressure data, or being difficult/expensive to calibrate. Our solution employs an elastic film that deforms under the action of applied loads. The deformation of the film is optically monitored. The deformation is modeled using finite element analysis in order to reconstruct the applied loads. The result is a continuous measurement of pressure and shear forces over the film surface. Also needed are technologies that can be transitioned to the flight line for rapid, machine-based detection of pressure loss, and external/internal damage that currently require hours of maintenance labor. The elastic film approach addresses this requirement based on the detection of changes in contact patch size, as well as local anomalies in the pressure and shear patterns produced by external or internal damage. BENEFIT: The tire shear and force sensor will directly improve Air Force internal testing capability with payoffs in safety of flight, tire wear and failure prediction, and more cost-effective inspection schedules. It will have broad commercial appeal to aircraft, automobile, truck, and heavy equipment tire manufacturers and testers. Development of a “roll-over” damage inspection capability would lead to significant reductions in flight line and depot maintenance hours.