Technical feasibility of a three-axis force transducer for measuring pressure and friction on the model die surface — prototype development

A new transducer for measuring normal and shear stress in physical modelling was designed and tested. From many methods of contact stress measurements, a local approach based on pin load cell was chosen. The sensing element employed was a stack of piezoelectric plates which measured three components of the force directly. The design process included a study of piezoelectricity in various materials, designing a prototype transducer and choosing an appropriate electronic circuit. The piezoelectric stack and the whole transducer were tested using a calibration rig capable of applying the normal and tangential force independently. Calibration results confirmed the suitability of the adopted concept and provided guidelines for proper design of the final transducer. In particular, a new calibration procedure was proposed which took into account interactions between the measured force components.