Collaboration in Modeling the Grinding of Silicon Carbide Fiber Reinforced Silicon Carbide Ceramic Matrix Composite

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Advanced materials which can maintain structural strength at high temperature are critically important for the energy efficiency and reliability of the aircraft engines and power generation turbines. The silicon carbide fiber reinforced silicon carbide (SiCf/SiC) is a new generation of material for such high temperature applications. Grinding using diamond abrasive is the final finishing manufacturing processes to achieve the part accuracy and surface integrity. The high-speed contact between the diamond abrasive and the brittle SiCf/SiC material during grinding may generate surface cracks, which will greatly affect the strength and reliability of SiCf/SiC components. Modeling brittle composite materials, to isolate processing conditions where fracture does not occur, is difficult using conventional approaches due to the small size of the reinforcing fibers (diameter about 10 microns) with respect to the bulk material. This research focuses on verifying the feasibility and limitations of using an alternative modeling approach to accurately predict the crack formation and find the damage-free grinding conditions for diamond grinding of SiCf/SiC. If successful the project's modelling approach can be applied to other ceramic reinforced materials and increase the competitiveness of US manufacturing companies servicing aerospace, defense, and energy industries. This research will be conducted in close collaboration with the Laboratory of Machine Tools and Production Engineering, an international leader in grinding research, at RWTH Aachen University in Germany, and aerospace industries within the US. While NSF is only supporting the research conducted in the US, this project enables US researchers to leverage research facilities not available in the US for the benefit of US industries and manufacturing interests. Students engaged on the project will be exposed to international perspectives, and research practices at other esteemed institutes enhancing their workforce readiness. Research findings will also be adopted in the curriculum of manufacturing courses to benefit a broad group of students and inspire the next generation of engineers. This research investigates the ability of the smoothed particle hydrodynamics (SPH) modelling approach to model and gain fundamental understanding of the material removal and damage mechanisms in SiCf/SiC grinding. A comprehensive experimental program will be used to evaluate the modeling outcomes and isolate model limitations. SPH is a particle-based, mesh-free simulation method developed to address technical challenges including the large negative rake angle cutting edge, random orientation and distribution of diamond grains, and large strain and high strain rate deformation and fracture of the SiC fiber, fiber-matrix interface, and matrix. The single grain diamond scratching of SiCf/SiC will first be studied through experiments and SPH modeling to identify SiC material models and SPH techniques. The multi-grain experiment and SPH modeling of the grinding of SiCf/SiC will then be carried out. The damage mechanisms will be investigated to isolate the damage-free diamond grinding conditions for SiCf/SiC. In summary, this research will advance the tools available to gain insights into fundamental knowledge of material removal and damage mechanisms in diamond scratching and grinding of SiCf/SiC and other ceramic matrix reinforced composites.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.