Coupled analysis of composite laminate with embedded magnetostrictive patches

Abstract

A new finite element formulation for composite laminates containing embeddedmagnetostrictive patches is studied using anhysteretic, coupled, linear properties ofmagnetostrictive materials, which will act both as sensors and actuators. Constitutiverelationships of magnetostrictive materials are represented through two equations, onefor actuation and the other for sensing, both of which are coupled through amagneto-mechanical coefficient. The coupled model is studied without assuming anyexplicit direct relationship with the magnetic field. This is unlike the uncoupled model,where the magnetic field is assumed to be proportional to the actuation currentand coil turns per unit length. Hence, both mechanical and magnetic (smart)degrees of freedoms are required to take care of the total mechanical and magneticenergy in the system. In this model, the elastic modulus, the permeability andmagneto-elastic constant are assumed not to vary with the magnetic field. Actuation andsensing coils are considered to activate patches and sense the changes in stress inpatches. When the actuator patch is excited dynamically by passing an alternatingcurrent through the actuation coil, it introduces stress in the structure due to themagneto-mechanical coupling effect, which in turn produces magnetic flux in thesensing patches. This magnetic flux generates open circuit voltage in the sensingcoils. A number of numerical experiments are performed to show the essentialdifference between coupled and uncoupled analyses. For this, static, frequencyresponse and time history analyses are performed in 1D structures. It is foundthat the ply sequence has a phenomenal effect on the overall response due tocoupling.