A high performance strain gage based on the stressimpedance effect in magnetic amorphous wires

The paper presents a study on the possibilities of using the Co based magnetic amorphous wires (MAWs) with nearly zero magnetostriction for measuring strains by exploiting the stressimpedance (SI) effect occurring on them. It is known that the SI is a particularization of the magnetoimpedance (MI) effect when a MAW is driven by an ac current and is subjected to mechanical stresses under constant magnetic field. Several parameters of influence have been investigated in order to obtain the best performances for a strain gage (SG) that is intended to be developed for finally building a high performance landslide transducer. Using a MAW of 20 mm length which is driven by a current of 10 mA and of frequency of 1 MHz, under induced initial torsional stress of 5π rad/m and a residual axial tensile stress of 55 MPa, we obtained a high sensitivity SG showing a gage constant of about 2100 and a linear range of ±200 ppm.

► A highly sensitive device for measuring strain is proposed in the paper.
► The working principle is based on the stressimpedance effect in amorphous wires.
► A sensitivity of over 10 times higher than that of semiconductor gages is achieved.
► The sensor has a linearity under 1% for a range of 200 ppm.
► The sensor must be supplied with 1 MHz ac current.