碳纤维/树脂复合材料与钛合金制孔过程的交互作用对其叠层构件加工损伤的影响机理

Along with the development of high-performance aircraft, the requirement of high connecting/assembling quality between carbon/epoxy composites and titanium alloy components becomes more and more urgent. One-shot drilling of carbon/epoxy composites and titanium alloy stacks is required to improve the performance of components. However, high quality one-shot drilling is a difficult problem and great challenge in aviation industry. The objective of this work is to study the damage generation during one-shot drilling of carbon/epoxy composites and titanium alloy stacks. The variation and distribution of stress/temperature field during machining is set as the starting point in the investigation. On the basis of theoretical analysis and experiments, the changing of mechanical properties of materials during machining is studied. And, the interaction effect between drilling process of the two materials (carbon/epoxy composites and titanium alloy) is discussed, as well as its influence on machining damage. The relationship among cutting force/temperature, mechanical properties of materials and machining damage is analysed. Besides, the effect of physical and chemical factors on wear mechanism of cutting tool is studied, combining with the research of stress/heat load impacting on the tool wear. And, the influence of tool wear on machining damage is investigated. After that, a strategy which used to obtain high-quality and long-life cutting tools is proposed. The importance of this research lies in not only improving the damage generation mechanism during drilling of the composite/alloy stacks, but also helpful to promoting the digital manufacturing and flexible assembly technology between composite components and titanium alloy components in our country.

随着航空飞行器使役性能要求的日益提高，对碳纤维/树脂复合材料与钛合金零部件高质量连接/装配的需求愈加迫切，其叠层构件的一体化高质量制孔加工已经成为航空制造领域亟待解决的难题和挑战。本课题以碳纤维/树脂复合材料与钛合金的叠层材料一体化制孔为研究对象，以制孔过程中应力场及温度场的分布和变化规律为切入点，在理论分析和试验观测的基础上，结合对制孔过程中材料力学性能演变规律的研究，探索两种材料制孔过程的交互作用及其对加工损伤的影响机制，并建立切削力/热-材料力学性能-加工损伤之间的映射关系。同时，探讨物理及化学因素共同作用下刀具的磨损机理及其对加工质量的影响，并开展力/热载荷冲击作用对刀具磨损规律影响的研究，提出高质量长寿命刀具的优化策略。本项目的研究成果不仅体现在对碳纤维/树脂复合材料-钛合金叠层材料加工损伤机理的推动作用，而且可以促进我国复合材料构件与钛合金构件数字化制造与柔性装配技术的发展。

C/E复合材料和钛合金在航空航天中的应用越来越广泛。为了实现复合材料构件和钛合金构件的装配连接，需要加工大量的螺接孔或铆接孔。C/E复合材料和钛合金叠层材料的一体化加工是保障加工效率的发展需求。然而，钛合金是典型的难加工材料，C/E复合材料在制孔过程中也极易产生多种加工损伤。C/E复合材料和钛合金叠层材料的一体化制孔加工面临着诸多与单一材料及传统金属材料构件加工完全不同的难题。本项目针对C/E复合材料构件和钛合金构件所需连接孔的加工，探讨两种材料加工过程的相互影响，研究加工损伤产生的主要影响因素及影响机理，并结合加工刀具磨损机理的研究，探讨连接孔的高质高效加工技术。研究成果揭示了复合材料和钛合金的加工过程存在明显的相互影响。特别是在复合材料和钛合金的界面处，由于钛合金的切削温度较高而复合材料树脂基体的耐热性能较差，导致界面处的复合材料产生性能衰变。复合材料性能的下降，不仅导致加工损伤的产生，而且对复合材料构件的使用性能也产生不利影响。同时，通过建立切削过程中切削刃处裂纹的扩展模型，探讨了在切削力热载荷共同作用下裂纹在切削刃处的产生和扩展过程，进而研究了硬质合金刀具的崩刃机理。根据螺旋铣削加工的特点，将螺旋铣削方法应用于复合材料/钛合金叠层材料的加工，将传统钻削与螺旋铣削的加工性能进行了对比分析，并研究了刀具刃数、圆角半径等工艺参数对螺旋铣削加工质量的影响。本项目的研究成果对碳纤维/树脂复合材料-钛合金叠层材料加工损伤机理具有一定的推动作用，而且可促进我国复合材料构件与钛合金构件数字化制造与柔性装配技术的发展。