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Z-pinned joints prepared by chemical vapour infiltration are widely used in ceramic matrix composite components. Excellent fatigue behaviour is important for structural safety. In this study, 2D C/SiC Z-pinned joints were loaded in axial direction of the pins under static and cyclic loading. Internal damage was monitored in situ by an acoustic emission system. The binding force between pin and hole is relatively strong. Meanwhile, the joints exhibite promising resistance to fatigue. The residual strength increased first with the fatigue cycles then decreased after 105 cycles. Microstructural analysis indicated that full-developed cracks and local stress redistribution resultes in the increase in the strength of the joints. The acoustic emission analysis also provides a supplementary understanding of the damage mechanism. The results show that damage fully develops at the early stage of fatigue. When the specimen is reloaded, less AE events are collected before the fatigue maximum stress.

Feather can morph in a quite convenient and effective way, which enables a bird with excellent flight abilities. Bird feathers have attracted the attention of researchers to reveal underlying physical mechanism of drag reduction or lift production. To investigate the microstructures and the mechanical behaviors of barbs, a series of barbs were manually cut from an eagle's primary feather to observe the cross-sections. How the barb was changed along both the rachis and barb was investigated in this research, and a "λ"-like cross-section with a tiny hook was observed at the right feet at each section. Afterwards, a measurement set-up system was developed to evaluate the leakage ratio of a feather followed by a numerical predicting approach based on CFD method. It is found that the air leakage increased linearly against the pressure and the predicted results coincide well with the experimental results. Finally, the influences of leakage of the flight feather on both steady and unsteady aerodynamics were studied.