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Dewetting is the main damage mode of composite solid propellants, and the research on the initiation mechanism and evolution process of dewetting damage is an important way to predict the mechanical properties and evaluate the life of propellants. In this paper, the experimental research and analytical methods of dewettingare reviewed at domestic and foreign from three dimensions: macro, meso and micro. On this basis, the reference solutions to the existing research problems are proposed, and the key research directions of interface dewetting in the future are pointed out. The analysis shows that the dewetting behavior of composite solid propellant is affected by multiple factors such as internal factors (par-ticles, matrix, bonding agent) and external factors (temperature and humidity, aging, strain rate, confining pressure). At present, the mechanism of dewetting is not clear, so it is urgent to conduct experimental analysis and numerical simulation research on the interface at the micro level to analyze the physical and chemical properties of the interface. On the meso scale, it is necessary to increase research in the dewetting theoretical model considering multi factor coupling, the mechanical property experiment of particlematrix interface, and the fine construction of meso scale simulation model. On the macro scale, the dynamic analysis method of propellant dewetting under multiple complex loading conditions will be the focus of future research.

During the service of pressure vessel, there are many kinds of structural damage. The main defect is pitting caused by corrosion of loaded materials, cracks are formed because of stress concentration in the pit position, and crack propagation leads to crack leakage. As an important parameter to characterize cracks, fatigue life is widely used in engineering to judge the safety and reliability of mechanical structures. In this paper, based on the two-parameter pit-crack model, the fatigue life of pressure vessel with multiple pits-cracks is discussed by using ANSYS finite element analysis software. The results show that the fatigue life of pressure vessels decreases with the existence of multiple pits and cracks, but with the increase of pit-crack spacing, the effect decreases gradually until it returns to a stable state. The effect of pit parameters and the ratio of crack length to depth on fatigue life has obvious interval effect. This paper can be used as a reference for failure assessment of multi-pit-crack pressure vessels.

Boron nitride/ethylene alcohol (BN/EG) nanofluids was synthesized by two-step method. The influence of dispersant on stability, thermal conductivity and viscosity was studied. The experimental results reveal that the stability of BN/EG nanofluids deteriorates rapidly with the addition of anionic dispersants and cationic dispersants, which has no practical application value. While, non-ionic dispersant can improve the stability and fluidity obviously and maintain the enhancement of thermal conductivity at the same time.