Sensing by Instrumented 3D Printed Pessary

A novel bi-material soft pessary ring fabricated by means of fused-filament-fabrication (FFF) with embedded strain gauges is developed. The ring is based on a highly flexible FFF compatible TPU for the pessary body, and carbon-doped TPU for sensing structure. Four strain gauges are located close to the toroidal surface and symmetrically across the circular section. Under constrained harmonic loading it is demonstrated that the sensorized pessary undergoes slow transient behavior and hysteresis. To compensate for the non-linear response, a modified Power-Law model is employed that successfully estimates the exerted shear loads for the trained excitations.