Highly Sensitive Screen Printed Strain Gauge for Micro-Strain Detection

In this paper a flexible and stretchable strain gauge was screen printed and tested for micro-strain detection. The strain gauge was fabricated by screen printing carbon ink on thermoplastic polyurethane (TPU) substrate and then encapsulated for protection from the effect of temperature and humidity. The strain gauge was bonded on to aluminium beams and the electromechanical response of the sensor was investigated by applying different loads. Resistance changes varying from 0.3 kΩ to 5.9 kΩ were observed as the loads were varied from 0.2 kg to 1.8 kg, with corresponding calculated gauge factors ranging from ~10 to ~20. The results demonstrate that the screen-printed strain gauge is highly sensitive and can be utilized for micro-strain (με) detection. The response of the fabricated strain gauge as a function of resistance is investigated and presented in this paper.