Analysis of the Diaphragm Thickness Influence in a FBG Pressure Sensor Response

This article aims to compare the influence caused by the diaphragm thickness in the pressure measured using fiber Bragg gratings (FBGs) sensors. Two diaphragms (with 1.2 mm and 2 mm thickness) have been 3D printed with flexible thermoplastic polyurethane (TPU). A polytetrafluoroethylene (PTFE) tube is installed in the diaphragm during printing, in order to house the FBG sensor and enhance its robustness. The experimental evaluation submitted the FBG-based diaphragms to pressure varying from 0.0 to 172.37 kPa using 6 steps with 34.47 kPa each one. The achieved sensitivities were 7.5 pm/kPa and 5.2 pm/kPa for the diaphragm of 1.2 mm and 2 mm, respectibely.