Development of a tri-axial load cell based on strain gages

Abstract

A tri-axial load cell of cantilever type for the measurements of an axial force (F-z) and two bending forces (F-x, F-y) was developed to study fracture toughness under mixed-mode loading condition. The full scale of load cell is +/-1.5kN axial force, +/-1.5kN bending forces, respectively. The load cell consists of three Wheatstone full bridge arrangements to increase the high sensitivity and compensate the ambient temperature. To decouple three forces components, active eight strain gages for the axial force and four gages for bending force are used in the bridge circuit. The calibration of load cell showed that the coupling effects of each force were almost negligible, and the load cell was found to have linear characteristics without any hysteresis. The accuracy was +/-0.6% of full scale (+/-1.5kN).