关键词: Z-pin, 复合材料, 纤维弯曲, 固化成型, 残余应力, 有限元仿真, 压缩性能

Abstract:

The Z-pinning technology can effectively improve the interlaminar properties of composite materials， yet the implantation of Z-pins causes fiber distortion， resin-rich zones， and reduced in-plane properties. This paper proposes a numerical method to predict the in-plane compressive properties of Z-pinned composites， with curing effects into consideration. A representative unit cell model is established by analyzing the fine morphology of the Z-pinned structure. Considering the time-dependent properties of the cure process， we develop a coupled thermo-chemo-mechanical multi-field model for Z-pinned structures. The residual stress field obtained from the previous calculation is introduced as a predefined field in the calculation of in-plane compressive performance， and the simulated results are in good agreement with the experimental results. It is found that a large amount of residual stress accumulates around the Z-pin during the cure. Therefore， under compressive loads， weaker material properties around the Z-pin will first develop crack defects， gradually extending to the resin-rich regions. The presence of fiber orientation， resin-rich regions， and cure-induced residual stresses significantly reduce the in-plane compressive performance of Z-pinned composites.

Key words: Z-pin, composites, fiber distortion, cure process, residual stress, finite element analysis, compressive properties