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The aircraft power supply system is the power source of all electrical equipment on board，thus its safety and reliability are pretty important. Against the backdrop of environmental protection and high-efficiency development needs，research and application of more/all electric aircraft technology with electric power as the core is advanced. The widespread use of electric drive devices and power electronic devices has led to the complexity of aircraft power supply system structure，which puts forward higher requirements for aircraft reliability，safety，testability and maintainability，so that researches on fault diagnosis technology for aircraft power supply systems are of great significance. In this paper，firstly the composition structure and respective functions of aircraft power supply system are introduced. Secondly，the development process of aircraft power supply system is outlined. Thirdly，the characteristics of typical domestic and foreign power supply systems are compared. Fourthly，the main failure modes，fault characteristics and failure causes of aircraft power supply system are summarized，and a design architecture of aircraft power health management system is proposed. Fifthly，the research progress of fault diagnosis methods based on model and data are reviewed，then，the characteristics of various diagnostic methods are evaluated from aspects such as accuracy，data demand，applicability and implementation difficulty. Finally，the challenges and development trends of fault diagnosis technology for aircraft power supply system are pointed out.

Multi-layer complex structures are widely used in large-scale engineering structures because of their diverse combinations of properties and excellent overall performance. However, multi-layer complex structures are prone to interlaminar debonding damage during use. Therefore, it is necessary to monitor debonding damage in engineering applications to determine structural integrity. In this paper, a damage information extraction method with ladder feature mining for Lamb waves is proposed. The method is able to optimize and screen effective damage information through ladder-type damage extraction. It is suitable for evaluating the severity of debonding damage in aluminum-foamed silicone rubber, a novel multi-layer complex structure. The proposed method contains ladder feature mining stages of damage information selection and damage feature fusion, realizing a multi-level damage information extraction process from coarse to fine. The results show that the accuracy of damage severity assessment by the damage information extraction method with ladder feature mining is improved by more than 5% compared to other methods. The effectiveness and accuracy of the method in assessing the damage severity of multi-layer complex structures are demonstrated, providing a new perspective and solution for damage monitoring of multi-layer complex structures. [ABSTRACT FROM AUTHOR]

In our work, the three-dimensional flow in stacks of biaxial E-glass fiber non-crimp fabrics (NCF) and unidirectional carbon fiber layers was monitored by the etched optical fiber sensors embedded inside the fabric stack. The influence of embedding sensors with a diameter of 200 µm on the flow was experimentally illustrated and discussed. The out-of-plane permeability of the two fabric materials was estimated with a radial infusion model using the in-plane permeability values as the prior knowledge. The assumed radius of the semi-ellipsoidal flow was derived and showed a good agreement with the results obtained by the best fit of the exact solution, which provides an approximate solution that simplifies the calculation process. The asymptotic form and the modified semi-ellipsoidal inlet radius method for the case of a non-negligible radius of injection tube compared to the fabric sample thickness were verified. The uncertainties related to the unknown flow pattern near the inlet were also demonstrated. The presented results facilitate the further development and standardization of out-of-plane permeability measurement methods with embedded sensors. [ABSTRACT FROM AUTHOR]