Evaluation of Additively Manufactured Parts in Disruptive Manner as Deformation Elements for Structural Integrated Force Sensors

Laser-based powder bed fusion (LPBF) as an additive manufacturing (AM) process allows the integration of sensors at any location within the manufactured part. This allows for manufacturing smart parts that can be integrated into complex structures for monitoring applications, as they can perform in situ measurements. Especially, monitoring of force and torque is gaining increasing interest. However, a proper strain transmission from the mechanically loaded part to the embedded strain sensing element must be ensured, as the performance of such sensors is strongly dependent on it. In this work, we present an approach for additively manufactured deformation elements in a disruptive manner with integrated strain gauges using a steel plate as a measuring element carrier. To evaluate the strain transmission, and, thus, the performance of the additively manufactured deformation elements, we compare them to a conventionally manufactured deformation element with identical geometry. The strain gauges are applied after manufacturing at locations with a proper strain, which are determined by finite-element analysis (FEA). Loading these additively and conventionally manufactured prototypes with 15N results in only 0.1% linearity and 0.2% hysteresis error. Furthermore, a nearly linear temperature behavior of manufactured prototypes with a TK 0 of up to 0.3%/10K and a TK C of up to 0.6%/10K is achieved. These results confirm that a proper strain transmission is ensured within the additively manufactured deformation elements, making them competitive with conventionally manufactured deformation elements. Thus, the disruptive manufacturing process introduced is suitable for fabricating structurally integrated force sensors based on strain gauges.