Manufacturing and characterization of strain sensor using additive manufacturing method

As virtual reality and robotics-related technologies advance, better sensor technology is needed to power these systems. In particular, most systems must interact with the human body or the environment while maintaining a high amount of mobility and flexibility. This has created a demand for flexible electronic devices, especially flexible strain sensors. This thesis study investigates the feasibility of additive manufacturing (AM) technology, which is a simple and cost-effective method to develop a flexible single-axis strain sensor. AM enables rapid production and prototyping of designs at relatively low cost. Fused deposition modeling (FDM) technology, one of the AM methods, was used to produce the flexible substrate of the strain sensor. Conductive silver material is injected into the upper layer of the sensor. The strain sensor is fabricated to approximately 20 mm x 60 mm. The thickness of the sensor is 2 mm. After this stage, the sensitivity of the sensor was determined by calculating the indicator factor from the experimental data. The results showed that the sensor exhibited high linearity and low hysteresis performance. Additionally, the displacement amounts of the strain sensor against the applied force were observed. Finally, tensile tests were performed to examine the elongation of the sensor in yielding. To prove the accuracy of real-time experiments, finite element analysis of the strain sensor was performed with the COMSOL program. COMSOL was also used to model the stress distribution and strain of the strain sensor. It has been found that the experimental results of the sensor are in good agreement with the simulation results. The results show that stress accumulation and permanent deformation play an important role in determining the functionality of FDM-fabricated sensors. The results of this thesis study demonstrate the potential of additive manufacturing to produce complex designs and sensor platforms for a wide variety of applications.