CFRP/钛合金叠层制孔过程中切削热对加工损伤和缺陷形成的影响机制

The key issue of the integrated hole-making in CFRP/titanium alloy laminated structure on the aircraft assembly process with low-defect needs to be resolved. The cutting heat generated in the integrated hole-making process is the source of the tool wear, the surge of cutting force, surface quality degradation and the defects generation. In this subject, the integrated hole-making in CFRP/titanium alloy laminated structure using helical milling and drilling process is investigated, the cutting temperature and cutting force are both experimentally measured, the effects of the cutting heat on cutting force and tool wear are studied, and the mechanisms of cutting heat conduction and the surge in the cutting force at the interface are investigated. The cutting temperature model including interface effects and the cutting force model using finite element method are created, the variations and its influencing factors of cutting temperature and cutting force are studied, and the relationship between cutting heat and cutting force is verified. The influence of cutting heat on the defects including delamination, fiber breakage and debonding is analyzed. The secondary damage on the machined surface of CFRP by the reason of titanium alloy scraps during the machining process is investigated. Finally, the method of alternating machining parameters is applied in the integrated hole-making process to improve machining performance and decrease machining damage. This project can provide theoretical basis and technical support for improving the quality and efficiency of aircraft and spacecraft assembly.

CFRP/钛合金叠层构件低损伤制孔是飞机装配急需解决的关键问题。切削热是导致叠层制孔刀具磨损严重、切削力剧增、表面质量下降及损伤严重等现象的溯源。项目以CFRP/钛合金叠层钻孔和螺旋铣孔为研究对象，搭建钻孔和螺旋铣孔切削温度、切削力测试平台，研究切削热对切削力、刀具磨损的影响规律和叠层界面处热传导规律；考虑叠层界面效应，建立叠层制孔温度场数学模型和切削力有限元仿真模型，研究切削热、切削力变化规律及其影响因素，探明热-力交互作用机制，揭示叠层界面效应诱发切削力激变的机理；分析热影响区CFRP分层、撕裂及脱粘等损伤缺陷形成机制，探究钛合金断屑、排屑及切削区温度场对CFRP已加工表面的二次损伤机理；提出叠层构件低损伤制孔的变工艺参数加工新策略。旨在提高叠层制孔质量、降低加工损伤，为我国大型航空航天器装配提供理论基础和技术支撑

CFRP/钛合金叠层构件一体化、低损伤制孔是飞机装配现场急需解决的关键问题。项目基于国家自然科学基金青年项目（编号：51405336），开展了钛合金螺旋铣孔、钻孔质量对比研究，分析了钛合金螺旋铣孔、钻孔过程中制孔精度、表面完整性的变化规律及其影响因素；开展了钛合金开孔件疲劳寿命试验及有限元仿真，揭示钛合金开孔件裂纹产生及扩展机理；开展钛合金、复合材料CFRP单层螺旋铣孔温度测试，研究了切削速度，切向每齿进给量和轴向切削深度对切削温度影响；开展了CFRP/钛合金叠层结构螺旋铣孔温度研究，重点分析叠层结构界面材料性能突变而诱发的冲击机理，探究叠层结构螺旋铣孔温度分布规律，探究叠层结构制孔加工表面的二次损伤机理，提出了适合叠层构件低损伤制孔的变工艺参数加工方法。