考虑砂轮表面形貌及工件缺陷影响的工程陶瓷磨削加工损伤行为研究

Grinding is one of the main means of precision and ultra-precision machining of ceramic materials, and the machining damage is closely related on the grinding wheel surface topography, workpiece defects and grinding parameters, and their inherent relationship is very complicated. Aiming at this problem, this project will investigate the damage behavior of engineering ceramics in grinding process by numerical simulation and experimental research. Starting with the characteristics and parametric description of the grinding wheel surface topography and the workpiece defects, a grinding wheel model which is used to describe the complex morphology and distribution characteristics of abrasive within grinding wheel surface will be established, and a workpiece model which contains some common material defects will be also built. Considering the influence of thermo-mechanical coupling of grinding zone, the temperature field model and heat conduction model will be established and a discrete element model for ceramic materials grinding process will be refined. According to the results of simulation and experiment of grinding, the inherent relationship of the grinding wheel surface topography and workpiece defects to the damage evolution mechanism of materials will be addressed. In addition, in order to reasonable matching of grinding wheel surface topography, workpiece defects and grinding parameters, a multi-factor and multi-objective optimization model will be built and verified by experimental investigation. Outcomes from this project will enhance and improve the research methods of processing damage mechanism on ceramic materials, and provide a technical guidance for improving the grinding quality of engineering ceramic materials.

磨削是陶瓷材料实现精密和超精密加工的主要手段之一，其加工损伤行为与砂轮表面形貌、工件缺陷以及磨削工艺参数等因素密切相关，且其内在关联十分复杂。针对该问题，本项目从数值仿真和实验研究相结合的角度开展工程陶瓷磨削加工损伤行为研究。从砂轮表面形貌和工件材料缺陷特征化和参数化描述入手，构建金刚石砂轮表面形貌模型以及陶瓷工件模型；建立磨削区温度场模型以及热传导模型，研究磨削区域热-力耦合作用，并完善陶瓷磨削加工仿真模型；结合磨削仿真与实验结果，阐明磨削过程中砂轮表面形貌及工件缺陷与加工损伤演化机制之间内在关联；构建磨削加工质量的多因素多目标优化模型，探索砂轮表面形貌、工件缺陷以及磨削工艺参数的合理匹配，并进行实验验证。通过本项目的研究，将有望丰富和发展陶瓷材料加工损伤机理的研究手段，并为陶瓷材料的高质量磨削加工提供技术指导。

工程陶瓷具有良好的硬度与耐磨性、耐腐蚀性、良好的热稳定性与化学稳定性等优点，被广泛地应用于机械、汽车、航空航天等领域。由于其固有的硬脆性这一特性，要想实现对陶瓷材料精加工和超精加工，磨削加工依然是目前的主要加工手段之一。但在磨削过程中由于磨削力与磨削热的作用，陶瓷工件会不可避免地出现表面/亚表面损伤，而这一在磨削过程中造成的损伤同样与砂轮表面形貌、工件缺陷以及磨削工艺参数等密切相关。.本项目开展了考虑砂轮磨粒形貌以及含缺陷陶瓷材料磨削过程的数值仿真，根据所观测的金刚石砂轮表面磨粒的形状、尺寸以及分布密度等，建立了考虑磨粒形状的砂轮离散元模型；并基于所观测到的陶瓷材料内部缺陷，进行参数化和特征化描述，建立了含缺陷的陶瓷材料离散元模型。同时，研究了磨粒形状以及分布密度对陶瓷材料加工质量的影响；陶瓷材料内部所含裂纹及缺陷对其本身力学性能的影响；并在磨削过程中构建了合适的热源分布以及热源移动模型，基于热辐射与热传导原理，开展了不同磨削工艺参数下的“磨削力-温度场-应力场”的相互耦合规律及工件材料响应行为的相关研究。此外，在本项目的支持下还开展了有关于散体材料颗粒流动性及3D打印等方面的研究。.本项目深入研究了陶瓷材料内部不同裂纹及缺陷对其本身力学性能的影响，仿真分析了考虑砂轮磨粒形貌与陶瓷材料内部缺陷时的磨削过程，并构建了考虑磨削热-缺陷-砂轮形貌等对陶瓷材料磨削加工质量影响的离散元仿真方法，丰富了陶瓷材料磨削的数值仿真手段，对优化陶瓷材料的磨削加工质量具有一定的指导意义。