Symmetric laminate with MS layer away from mid plane

The same symmetric laminate with MS layer placed in the seventh layer in place of earlier position in the middle will make it asymmetric. When the laminate is subjected to alternating current, the compression in MS layer away from centre will bring bending in consideration. Stress, strain and voltage profile of composite laminate with 7th layer from the top having Terfenol-D is presented in Figures 33.7, 33.8 and 33.9.

Figure 32.7 Stress variations at various interfaces and in MS layer at the time of delamination when the laminate is subjected to mechanical load along with actuator current

Figure 32.8 Strain variations at various interfaces and in MS layer at the time of delamination when the laminate is subjected to mechanical load along with actuator current

Figure 32.9 Open circuit voltage in MS layer when the laminate is subjected to mechanical load along with actuator current

Figure 32.9 suggests that the MS layer away from the mid plane is more effective as it helps in generating higher induced voltage of 67 mV in the sensing coil due to bending effect. At the time of delamination the MS layer has a compressive stress of approximately 64.5 MPa and the delamination will occur in the outer most layer due to tensile stress of approximately 17.82 MPa. The laminate will have a strain of 232 micron at the interface in its outer most layer.