Numerical and experimental investigations of conventional and sensor-integrating jaw couplings

Abstract The possibility to directly measure the torque transmitted from a motor to a machine is not an easy task. To alleviate this, in the current work a new prototype of a sensor-integrating jaw coupling is proposed. In the prototype, double-sided counterbores are drilled into the teeth of the gear rim. Afterwards, dielectric elastomer sensors (DESs) are inserted, which are connected to strain amplifiers at both ends. The change in the capacitance of the sensors can then later be used to predict the torque. In the present work, the new prototype of the sensor-integrating jaw coupling is experimentally and numerically evaluated. Additionally, the manufactured DESs were subjected to multiple compressive loading-unloading cycles using a tensile testing machine to characterize them. It was shown for the first time that the coupling is able to detect the application of a torsion angle independent of the loading direction, i.e. clockwise or counterclockwise. Additionally, the correlation between the applied load and the measured change in capacitance is very good. Furthermore, a framework for the numerical simulation of both conventional and sensor-integrating jaw coupling is given and validated with experimental data. The model was implemented in the finite element software ABAQUS. To account for the viscous material properties of the material of the gear rim a hyper-viscoelastic material model was used. For the prediction of the torque, the numerical model yielded excellent results when compared to the experimental data.