Dynamic response and failure mechanisms of a laser-fabricated flexible thin film strain gauge

Abstract

Increasing demand for smart devices has spurred the development of advanced sensors with smaller and more adaptable form factors. The integration of thin film technology into sensors such as strain gauges has the potential to reduce their size and allow for the use of new manufacturing techniques. However, fabrication of reliable thin film strain gauges remains a challenge. Here, we demonstrate the manufacture of a 1025 Ω flexible thin film strain gauge using a UV laser patterning process and evaluate its dynamic tensile response. The strain gauges exhibit a sensitivity comparable to conventionally fabricated commercial alternatives, and can reliably survive 106 cycles up to 1750 µε. Above this strain level, several failure mechanisms are identified, with unique electrical responses corresponding to physical damage observed on the strain gauges. These findings provide a guide to diagnose thin film strain gauge failures, demonstrate an unconventional fabrication technique, and show their potential for use in long-term dynamic load sensing applications.