An electromagnetic method for measuring young´s modulus for iron, steel, and nickel rods

If a rod of iron, steel, or nickel, is placed axially in a solenoid which is excited by direct current, and if the rod is caused to vibraste longitudinally with its natural frequency, the changes of mechanical stress will produce corresponding changes of flux in the rod, so that an e.m.f. of the same frequency will be induced in a search coil which embraces the masgnetized part of the rod. The frequency of this e.m.f. is measured by means of oscillograms, from which the value of Young´s modulus is easily found.