In this paper, the repair of a cracked beam under an externalload, employing the electro-mechanical characteristic ofthe piezoelectric material to induce a local moment, is presented.Conceptually, an external voltage is applied to actuate apiezoelectric patch bonded on the beam to effect closure of thecrack so that the singularity induced by the crack tip may beeliminated. Using a simply supported beam as an illustration,the actuation voltage required is obtained from an equationcontaining variables such as the applied force, and thegeometric and material properties of the beam and thepiezoelectric material. It is shown mathematically andnumerically that the voltage required (a)decreases linearly asthe distance between the force and the location of the crack isincreased, (b)varies quadratically with the position of thecrack along the length of the beam, and (c)decreaseshyperbolically as the ratio of the thickness of thepiezoelectric patch to that of the beam increases.
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