Gaoming Dai

Microscale damage mechanisms and degradation of fiber-reinforced composites for wind energy applications: results of Danish–Chinese collaborative investigations

Recent research works in the area of experimental and computational analyses of microscale mechanisms of strength, damage and degradation of glass fiber polymer composites for wind energy applications, which were carried out in the framework of a series of Sino–Danish collaborative research projects, are summarized in this article. In a series of scanning electron microscopy in situ experimental studies of composite degradation under off-axis tensile, compressive and cyclic loadings as well as three-dimensional computational experiments based on micromechanics of composites and damage mechanics, typical damage mechanisms of wind turbine blade composites were clarified. It was demonstrated that the damage mechanisms in the composites strongly depend on the orientation angle of the applied loading with the fiber direction. The matrix cracking was observed to be the main damage mechanism for tensile axial (or slightly off-axis axial) loading; for all other cases (off-axis tensile, compressive and cyclic tensile loadings), the interface debonding and shear control the damage mechanisms.

Hierarchical nanoreinforced composites: Computational analysis of damage mechanisms

The potential of hierarchical composites with secondary nanoreinforcement is discussed and analysed on the basis of the computational modelling. The concept of nanostructuring of interfaces as an important reserve of the improvement of the composite properties is discussed. The influence of distribution, shape, orientation of nanoparticles (carbon nanotube, graphene) in unidirectional polymer matrix composites on the strength and damage resistance of the composites is studied in computational studies. The possible directions of the improvement of nanoreinforced composites by controlling shapes, localization and other parameters of nanoreinforcements are reviewed.