摘要 |
An improved method of sensing strain allows measurements of stress, torque, vibration and other loads imposed on a body without physical contact between the body/sensor and the monitoring equipment. An induction loop is at least partially comprised of a magnetostrictive material with a non-linear current-voltage relationship. An excitation device such as a coil is used to induce an AC response in the sensor. The non-linear response to the induced current is received by a sensing device such as a sensing coil, and the output thereof is filtered. The excitation device and sensing device are located in operative proximity to the sensor, but need not be in contact therewith, allowing easy measurement in small spaces, under harsh conditions, or of moving bodies such as drive shafts. The non-linear response of the sensor induces easily detectable harmonics of the base frequency of excitation. These harmonics may advantageously be measured as well.
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