Fracture behavior of an interface crack in a magnetoelectric sandwich structure under electric field: Effects of the poling directions

Magnetoelectric (ME) sandwich structure is a common form in device applications. Poling directions of component materials are essential for the improvement of ME device properties. In this paper, the effects of the electric and magnetic poling directions on the interface fracture of a ME sandwich structure are investigated by integral transform and singular integral equation techniques. The expressions of the normalized stress intensity factors (NSIFs) are derived, and some numerical examples are presented. It is found that the poling direction of active layer can greatly affect the interface cracking mode. And the crack propagation can be promoted or impeded by adjusting the applied field. The structure with a larger volume fraction of active material will be more likely to crack.

FFT phase-field model combined with cohesive composite voxels for fracture of composite materials with interfaces

A framework for damage modelling based on the fast Fourier transform (FFT) method is proposed to combine the variational phase-field approach with a cohesive zone model. This combination enables the application of the FFT methodology in composite materials with interfaces. The composite voxel technique with a laminate model is adopted for this purpose. A frictional cohesive zone model is incorporated to describe the fracture behaviour of the interface including frictional sliding. Representative numerical examples demonstrate that the proposed model is able to predict complex fracture behaviour in composite microstructures, such as debonding, frictional sliding of interfaces, crack deviation and coalescence of interface cracking and matrix cracking.

Green Preparation and Dry Sliding Wear Properties of a Macro-ZTA/Fe Composite Produced by a Two-Step Method

In this paper, a two-step method, rapid-flow mixing followed by high-pressure compositing was used to prepare a macro-ZTA (ZrO2-toughened Al2O3) particles reinforced high chromium cast iron (HCCI) matrix composite. The method is based on the squeeze casting process without general casting pollution problems. The microstructure, mechanical properties and dry sliding wear performance of the fabricated composite were investigated. The results showed that the particles were distributed uniformly throughout the iron matrix and a tightly bonded interface was obtained. Under dry sliding wear conditions, the wear resistance of the composite was significantly improved in comparison with the HCCI alloy, and the relative wear resistance was 1.8 and 2.9 times at the applied load of 300 and 900 N, respectively. When the load increased from 300 N to 900 N, the wear characteristics of the composite changed from shallow and narrow grooves and scratches to damages in the form of fragmentation of particles, transfer layer and interface cracking.