Coating is one of important parts in fiber-reinforced composite. Under cyclic loading, the effect of coating on interfacial fatigue is investigated based on double shear-lag model. Stresses of components are obtained. Relationship for analyzing interfacial debonding is established by the Paris Formula. Interfacial fatigue on fiber/coating and coating/matrix is simulated. It can be seen that interfacial debonding on different interfaces meet energy conservation law in general.

The preparation of alumina silicate refractory fiberboard by wet vacuum filter molding process, alumina silicate fibre is the matrix material, and high-temperature resistance adhesive is the agglutinant. Experiments made in conditions of no liquid glue, and not adding fiber, influence of cycling time on liquid glue concentration, density of fiberboard, and retention of cementing compound was studied; effect of density of fiberboard on thermal conductivity is also discussed. The results showed that the optimum liquid glue concentration is 9.41%, cycling time is 28h (replenish liquid glue after 28h). Density of alumina silicate fiberboard is 289kg/m3, and alumina silicate fiberboard can resistance to 1200 °C.

Bonding degradation at interface is one of main damage forms of composites, especially under fatigue loading. Interfacial bonding degradation of FRC under two-stage tension loading is studied, which is base for variable-amplitude cyclic loading existing widely in actual engineering. Based on the shear-lag model and considered the asymmetry of interfacial damage, the mechanical governing equations of fiber and matrix are established and related solutions are obtained firstly. Two kinds of loading models are chosen, one is low-high alternate loading, and the other is low early and high late loading. By the aid of the Paris law and the energy release theory, a relationship between debond rate and cycle number is established. Then the interfacial debonding is simulated under the two-stage tension loading. The rules of the crack growth are analyzed for low-high two-stage loadings. It is found that stress amplitude has great influence on interfacial debonding under two-stage loading. Low stress amplitude in a certain range can postpone interfacial bonding degradation. And interfacial damage extent is greater than that under constant-amplitude fatigue loading. Present study is helpful for analyzing the fatigue damage of engineering materials and structures.