MILITARY AIRCRAFT TYRES – Monitoring of Operating Conditions

The application of MEMS technologies developed from the Department of the Polytechnic, with this research, has been directed toward an area not yet sensorized like that of a tire for military aircraft. Theaereo2 wheels of the main landing gear of an aircraft military jet are characterized by a peculiar phenomenon of heating of the tires generated by severe operational conditions of employment/taxiing, takeoff, landing phases and  emergencies during operations.

Structural Loads cyclically deform the tyre carcass. and induccarrelloe a deformation work in the various layers of materials, linked by the rubber compound, that make up the structure of the tire, the internal work of deformation and the heat of the use of the brakes raises the internal temperature of the carcass but even more in that salient structural area called Bead Toe / Tyre bead.

The temperatures of the brakes package can exceed easily 500 ° C in a normal braking and would reach 1000 ° C in case of aborted take-off or emergency landing. In extreme conditions the temperature may be such as to cause local failure of the rubber compound in the area of Tire Bead/Beadpneumatico Toe. This local failure is due to the loss of structural capability of the rubber because the local compound temperature. Therefore the  structural collapse starts when the bond between the carcass and steel cable is loosening. This phenomenon, not measurable on the outer tire surface, is hidden due to the poor heat conductivity of the rubber of the structure of the tire. Hence the need for a dedicated MEMS Sensor System that is able, using the salient physical parameters affecting the structural integrity of tire bead, carry out:

  • monitor taxiing / take-off / landing over the entire operating cycle of an aircraft
  • store the operating history in terms of the significant parameters.

The research has enabled us to develop a device insertedsensore into the tire, able to monitor and collect data on thermal conditions and wear of the tire in real time. The system has been realized through the development of MEMS sensors integrated into the tire itself, by monitoring the operating environment conditions (temperature, pressure, loading conditions).test

Level reached by the current state of research is TRL 5.

The next steps of the research are directed to the engineering of a final optimized solution to be installed as “stand-alone” for an initial operational test of the entire system on an aircraft for ground trials.

This program was delivered to Italian MoD with collaboration of Politecnico di Torino – Department of Applied Science and Technology

Aircraft Nanotechnology reinforcement and restoration of structural integrity

Created from the need to ensure the basic structural repair and maintenance of structural parts of military aircraft and improve structural maintenance activities during their operational life, specific research has set itself the objective of experimental activities for the realization of new “nanostructured repairers materials capable to integrate with conventional materials used on aircraft.nanotube

These new materials demonstrators were made blending CNTs (Carbon Nano Tubes – Carbon Nanotubes) with known polymers and already in use in the industry.
nanotubo

The results obtained in this experimental campaign were encouraging, allowing in the laboratory to verify the effectiveness, with the achievement of recovery of about 98% of the initial structural capacity of the undamaged aluminum sample.

Pressa
To achieve this goal the research program was carried out experimentally reproducing the method applied to the repair of cracks on aluminum materials, simulating in the laboratory the damage of a specimen (crack) with the subsequent application of a patch repair with binder based on the new composite consisting of an industrial polymer and CNT. Level reached by the current state of research is TRL 4.

The maintenance or restoration of the operational efficiency of military aircraft requires the use of advanced technologies for both aspects of structural integrity, and for those maintenance. This is even more valid in the case of restoration of structural damage to aircraft caused during use in the service of the same, or as a suitable ABDR method of repair in operating environments defined as “out of area”.aereo Among the innovative materials most frequently used in the aviation environment, the carbon fibers occupy a leading position. These materials, however, are particularly sensitive to concentrated and/or impulsive loads which stress the material locally with the risk of serious structural damage. To date, interventions to repair any damage resulting from these stresses are invasive and very time consuming. They also require specific tools and an environment equipped to ensure the acceptability of the repaired component. It is supposed to activate a program of research aimed at defining a method adapted to perform such maintenance and repair in a non-invasive, reconstituting the structural continuity to the original static value while providing elements of verification of recovery of the characteristics of the repaired part/area. This program should, furthermore, be in position to identify and provide portable prototypes of diagnostic tools that enable extraordinary maintenance / repair in those operating “out of area” environments This mode of operation could allow simplified interventions, with the minimum of special equipment, restoring the damaged area/part quickly and rapidly, with the result thus reduce the management costs of the aircraft itself.

This program was delivered to Italian MoD with collaboration of Politecnico di Torino – Department of Applied Science and Technology