Analytical modelling of side grinding of orthogonal laminated SiCf/SiC composites based on effective elastic properties

SiCf/SiC composites have been applied in numerous fields owing to their outstanding properties including high specific strength and high specific modulus. However, defects can be produced during grinding because the composites are hard and brittle. Moreover, the fabrication process of laminated SiCf/SiC composites is complex and unstable, resulting in large differences in their elastic properties. Therefore, the effective elastic properties of composites must be obtained through theoretical analysis. In this study, the anisotropy of orthogonal laminated SiCf/SiC composites and the fracture removal mechanism of the brittle material were both considered to develop a more accurate model. The effective elastic constants of the laminated composites were calculated using a macromechanical analysis. The grinding process was divided into the ductile, ductile-to-brittle transition, and brittle stages for analysis by the critical cutting depth. The modelling development was based on the interaction between the diamond grains and the workpiece. Substituting the effective elastic constants into the model, the predicted value is in agreement with the experimental value. The cutting force value exhibits a non-linear decreasing trend with increasing spindle speed but increases linearly with increasing feed rate and cutting width. The spindle speed and cutting width have more influence on the cutting force than the feed rate. Increasing the spindle speed and decreasing the feed rate and cutting width can reduce the cutting force. The model can be applied to adequately evaluate the effective elastic properties of laminated SiCf/SiC composites and effectively improve the grinding processes and machining efficiency in future applications.

Automated summary

SiCf/SiC composites have outstanding properties and are widely used, but their hard and brittle nature can lead to defects during grinding. This study developed an accurate model by considering the anisotropy of laminated SiCf/SiC composites and the fracture removal mechanism of brittle materials. The effective elastic constants of the composites were calculated, and the grinding process was analyzed based on the critical cutting depth. The model showed good agreement with experimental results and can be used to evaluate the elastic properties of laminated SiCf/SiC composites and improve grinding processes and machining efficiency.