Interaction integral method for thermal fracture of nonhomogeneous magneto-electro-elastic materials

This paper focuses on the thermal fracture performance of magneto-electro-elastic (MEE) materials and proposes a new interaction integral (I-integral) method for extracting the key fracture parameters, including stress intensity factors (SIFs), electric displacement intensity factor (EDIF) and magnetic induction intensity factor (MIIF). After introducing the integrals along the interfaces with mismatched thermal properties, the I-integral is strictly proved to be independent of the integration domain size. This domain-independence is numerically validated for nonhomogeneous and discontinuous MEE materials (relative deviation <1%). Through the combination with the extended finite element method (XFEM), the developed I-integral method is employed to study thermal crack problems of MEE materials. The results show that the I-integral can achieve high numerical accuracy in determining the intensity factors. The thermal boundary condition of crack surface affects the intensity factors significantly. Finally, this paper focuses on the thermal fracture of laminated and fiber reinforced MEE composites. As for MEE composites (BaTiO3/CoFe2O4), the SIFs increase as the volume fraction of PM (CoFe2O4). Reducing the percentage of piezomagnetic phase can enhance the fracture resistance of MEE multiphase composites. At the identical volume fraction of components, the fracture resistance of fiber-reinforced MEE composites is generally better than that of laminated MEE composites and the PE-fiber composite exhibits greater fracture resistance than the PM-fiber composite.