In situ experimental study on possible strengthening and toughening mechanism of interlaminar pores in carbon fiber orthotropic laminates

Abstract

In order to study the regulation mechanism between the internal micro-pores and the mechanical properties of carbon fiber orthogonal laminated composites. In this paper, a kind of carbon fiber orthogonal laminated composite with different types of interlaminar micro-pores was carried out in-situ loading experiments by SR-CT, and the internal fibers, pore microstructure and damage of the sample in the process of progressive failure were tracked in the whole field and in real time. Through in-situ experiments, special phenomena such as three times reduction progressive failure of the material loading curve, secondary cracking of the fiber layer, and crack arrest by porosity was observed, Furthermore, through the analysis of the two special stages of strength improvement and toughness enhancement of the loading curve, it is found that the strengthening mechanism of the orthogonal laminated structure to realize the repeated strength improvement of the material by controlling the interlaminar alternating shear action, and the toughening mechanism of crack tip passivation induced by micro-pores. It provides a possible way to realize the strengthening and toughening of composites through the design of microporous structure.