Sensing of delamination in laminated composite beams using multiple magnetostrictive patches

Smart Composite laminates with multiple magnetorestrictive patches have been fabricated, one patch is for actuation and the other patch is for sensing. Horse-show type coil arrangement is used for actuation and sensing, which contains two arms, one arm is used for actuation and the other arm for sensing. Delamination sensing is carried out for composite laminated beam specimens, one with delamination and the other without any defect or damage. Actuation coil is used to induce stress in the magnetostrictive material, sensing coil is used for sensing to measure the induced open circuit voltage. Due to delamination, the stress produced in the magnetostrictive patch changes and that alters the magnetic flux through the sensing coil. This causes a change in the induced open circuit voltage across the sensing coil. The paper presents, the sensing of delamination in composite laminates using multiple magnetostrictive patches with horse-shoe type coil arrangement. The difference in the open circuit voltage with and without delamination is treated as delamination sensing voltage. For theoretical modeling, different models of the laminated composite beams with magnetostrictive sensors and actuators have been developed for the beams with and without delamination. Finite element analysis is carried out using NISA finite element software. Numerical values of open circuit voltage verses actuation current for both the experimental and computational studies are presented. Comparison of experimental and the computational studies shows that there is a good agreement between both the results obtained. Hence, the modeling method is very efficient and may be very much useful for the further studies related to the smart structures with intelligent materials.