Experimental evidence of end effects in magneto-electric laminate composites

This paper experimentally and theoretically studies the magneto-electric (M-E) responses of layered magnetostrictive and piezoelectric composites. A total of three different piezoelectric volume fractions of 0.17, 0.29, and 0.44 were prepared to investigate the strain variation in the sample and the effective M-E voltage coefficient (alpha) over bar as a function of bias magnetic field H-bias. Analytical modeling involving uniform strain, shear lag only, and shear lag plus demagnetization was performed and compared with experimental measurements. The results demonstrate that the uniform strain theory significantly overestimates the measured strain and (alpha) over bar values. This discrepancy is physically attributed to shear lag and demagnetizing effects. The analytical models involving shear lag and demagnetizing effects agree with the experimental results well within 5%. (C) 2007 American Institute of Physics.