Design, Development, and Calibration of Octagonal Ring Type Dynamometer with FEA for Measurement of Drilling Thrust and Torque

Abstract In this study, the design, development, and calibration of a strain-gauge–based octagonal ring type tool dynamometer was carried out. This dynamometer has the capacity to simultaneously measure thrust and torque during drilling operation. The thin strain ring theory was used for finalizing the dimensions of strain rings. Finite element analysis was carried out to compare theoretical strains with the experimental values and to finalize the location of strain gauges. The thrust force and torque were measured by eight strain gauges, each forming a Wheatstone bridge circuit, converting the deflections of elastic strain rings to proportional electrical signals. A suitable data acquisition system was used for recording the thrust and torque in a computer system. Calibration curves were plotted by applying known thrust and torque repeatedly. It was observed that the designed tool dynamometer is capable of measuring the cutting forces satisfactorily.