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The nonlinear effects of geometry, material and contact are considered, the finite element analysis（hereinafter FEA） method of composite stringer out-of-plane tension failure is established precisely by using Hoffman material failure criteria and Newton-Raphson increment iteration method. A verification test is designed to test the failure load and failure mode of three different stringer configurations.Then the load-displacement curve is drawn to verify the validity of the FEA method.The influence factors of out-of-plane tension failure of composite stringer are studied, which can guide the strength design of aircraft.

Rotating blades are key components in aircraft engine, the vibration characteristics and vibration reduction technology is rather important for engine performance, structural integrity, and work reliability. The dry friction damping structure is most widely used in all kinds of blade vibration suppression method. Firstly, the dynamic modeling and development of the rotating blade dry friction damper are described in detail. Then, the analysis method and development status of the damping characteristic of the dry friction damping structure for rotating blades are introduced. Finally, four types of models are introduced, including blade-ground and blade-blade models based on different structure, dry friction damping mathematical model based on Coulomb law of friction, dry friction damping contact model based on contact point, and dry friction damping contact model based on the relationship of relative motion, so as to provide theoretical and technical support for the modeling design, improving reliability and efficiency of rotating blade damping structure, and reducing vibration and prolonging life.

It is of important significance to study the vibration characteristics and vibration suppression technology of aero-engine rotating blades to improve the engine performance, structural integrity and working reliability. The development about experiment of vibration and response for rotating blade with dry friction damper is summarized. Device, excitation method and dynamic characteristic method used in vibration test for rotating blade with dry friction damper are discussed emphatically. Experiment of vibration and response for rotating blade with dry friction damper are divided into two types: non-rotating test and rotating test. According to present situation of experiment of vibration and response for rotating blade with dry friction damper, new research directions are suggested as follows: establishment of test equipment model library, which according to the different ten on structure and angle of adjacent blade; exploring the coupling loading method for high frequency and measuring method of vibration response; investigation on excitation method more in line with real environment, developing the high resolution measure method of vibration by using the strain gauge and sensor.

Nickel oxide (NiOX) is a desirable hole‐transporting material for perovskite solar cells owing to their merits of low‐cost, stable, and readily scalable. However, the NiOX|perovskite interface suffers from serious recombination and poor photostability because of the interfacial redox reactions. Herein, NiOX nanoparticles with tunable size have been synthesized at low temperatures by controlling the reactivity of the hydrolysis reaction. A self‐assembled monolayer composed of a ruthenium complex, i.e., C106, is then introduced to optimize the interfacial properties. The C106 molecule chemically bonds to NiOX via carboxyl acid group, which passivates the surface defects of NiOX and suppresses the negative redox reaction at the interface. The modification leads to an improvement in perovskite film morphology, crystallization, and band alignment. As a result, the efficiency of solar cells has been improved from 18.1% to 20.5%. More importantly, the modified solar cells retain >80% of their initial performance after continuous operation under 100 mW cm−2 irradiation for 800 h, which is much enhanced than the unmodified devices. [ABSTRACT FROM AUTHOR]

The leader–following consensus of linear heterogeneous multiagent systems is investigated in this paper. To comply with the most practical scenario, the communicating topologies among agents are assumed to switch stochastically and driven by a continuous‐time discrete‐state Markov process, whose state space corresponds to all the possible topologies. A novel distributed adaptive compensator is designed for the followers to reconstruct the exogenous signals without knowing the Laplacian matrix who is regarded as a global information, and sufficient conditions are given to ensure the compensator converges to the dynamic of the leader asymptotically in the mean square sense. Then, based on the compensator, we solved the consensus problem both by distributed state and measurement output feedback control schemes under output regulation framework, which allow followers to have nonidentical state dimensions. Finally, the theoretical results are demonstrated by a numerical example. [ABSTRACT FROM AUTHOR]

Hypersonic vehicles encounter hostile service environments of thermal/mechanical/chemical coupling, so thermal protection materials are crucial and essential. Ceramizable composites have recently attracted intensive interest due to their ability to provide large-area thermal protection for hypersonic vehicles. In this work, a novel ceramizable composite of quartz fiber/benzoxazine resin modified with fused SiO2 and h-BN was fabricated using a prepreg compression molding technique. The effects of the fused SiO2 and h-BN contents on the thermal, mechanical, and ablative properties of the ceramizable composite were systematically investigated. The ceramizable composite with an optimized amount of fused SiO2 and h-BN exhibited superb thermal stability, with a peak degradation temperature and residue yield at 1400 °C of 533.2 °C and 71.5%, respectively. Moreover, the modified ceramizable composite exhibited excellent load-bearing capacity with a flexural strength of 402.2 MPa and superior ablation resistance with a linear ablation rate of 0.0147 mm/s at a heat flux of 4.2 MW/m2, which was significantly better than the pristine quartz fiber/benzoxazine resin composite. In addition, possible ablation mechanisms were revealed based on the microstructure analysis, phase transformation, chemical bonding states, and the degree of graphitization of the ceramized products. The readily oxidized pyrolytic carbon (PyC) and the SiO2 with a relatively low melting point were converted in situ into refractory carbide. Thus, a robust thermal protective barrier with SiC as the skeleton and borosilicate glass as the matrix protected the composite from severe thermochemical erosion and thermomechanical denudation. [ABSTRACT FROM AUTHOR]