Thin Membrane with “Human Touch” Sensitivity: Body Pressure and Temperature Measurements with Optical Fiber Sensors

This work is focused on the design and manufacturing of an adaptive sensorized “Human Touch” membrane for medical bandages monitoring. The designed technological demonstrator consists of a polyurethane elastomeric shell with a thin composite supporting core (glass reinforced fibers and epoxy matrix). Fiber Bragg Grating Sensors (FBGS) embedded within this core allow to detect blood pressure with the aim of adjusting the tightness of the bandage so that it does not block the blood flow of the patient. At each FBG sensor, the membrane has a protrusion (a “button”) which amplifies the pressure on the sensor applying a longitudinal deformation to the fiber itself. To achieve this effect, the optical fiber must also be supported by two rigid constraints at both sides of the FBG sensor by inserting the composite core provided by circular holes in correspondence with the elastomeric button (and therefore the sensor). This core provides the additional function of obtaining the membrane stiffness necessary to guarantee a mutual decoupling in the presence of several FBG sensors within the membrane. After having described the main steps of the technological process developed for the manufacturing of the device, the subsequent calibration and validation tests carried out are reported in the second part of this memory. In particular, the membrane was applied to the bandage of an arm to evaluate the ability of the device to monitor both the bandaging action of the leg, giving feedback to the health worker and the period of maintenance thereof to avoid incorrect bandages.