NUMERICAL ANALYSIS OF COMPOSITES EMBEDDED WITH MAGNETOSTRICTIVE MATERIAL FOR SENSING CAPABILITY

摘要

In this paper, numerical models are constructed to analyze the magneto-mechanical interaction in a laminate embedded with terfenol-D (TD) for sensing purposes. The first model is a linear 3D model constructed in multi-physics finite element software and examines mechanical and magnetic sensing parameters of a sensing layer embedded in a composite laminate with a delamination along the sensing layer. The structural plies in the model are defined with the anisotropic properties of T300/ carbon fiber reinforced polymer (CFRP) plies. The results of the first model show that there is a local change in stress and strain in the region of the delamination. However, by assuming the magnetic permeability is constant in the constitutive sensing equation, the sensing parameter (magnetic flux density) does not change as a function of stress but only magnetic field intensity. The second model is a 2D boundary element model constructed in FADD2D that analyzes the stress intensity factors generated by a crack in a beam of similar geometry and loading configuration. It is loaded mechanically through two endpoints on a beam and the crack is offset from the center of the beam. The results of the second model show no significant stress increase in the crack region due to the Poisson's effect creating crack closure on the crack. These models are used to analyze the mechanical and magnetic mechanisms that allow Terfenol-D to be used as an embedded sensor in composites.