耦合冷却式柔性电磁成形技术电磁-热-结构耦合问题与材料成形性能研究

It is urgent for advanced manufacturing industries such as aerospace and automotive industry to build a clean, efficient and internationally competitive manufacturing technology system for making cutting-edge breakthroughs. Electromagnetic forming (EMF) fits the needs of the new age due to its high speed, flexibility, and environmental-friendliness. However, its industrial application has been restricted by the flexible electromagnetic force loading problems and the coil temperature rise issue. To solve these problems, this project adopts a distributed flexible coil to achieve flexible electromagnetic force and uses coupled cooling method to reduce the coil temperature rise, based on which a flexible electromagnetic forming with coupled cooling method is proposed for the first time. The following researches will be carried out: 1) electromagnetic-structural coupling analysis in electromagnetic forming process and electromagnetic force distribution with flexible coils; 2) electromagnetic-thermal coupling analysis in coupled cooling process and the coil temperature distribution; 3) system design and device development regarding flexible electromagnetic forming with coupled cooling method; and 4) material performance and microscopic mechanism of aluminum alloy treated with flexible electromagnetic forming with coupled cooling method. Through these researches, this project expects to shed some light on the electromagnetic-thermal-structural coupling problems and reveal the macroscopic and microscopic mechanism of material formability; as well as to solve two difficulties in existing electromagnetic forming and promotes industrialization application of electromagnetic forming, so as to contribute its share to supporting the advanced manufacturing industry towards the shift of intelligence, high-efficiency and environmental friendliness.

航空航天、汽车工业等先进制造领域亟需构建一种清洁、高效、具备国际竞争力的关键制造技术体系形成前沿突破；电磁成形技术因其高速、柔性、绿色等特点完美契合时代需求并具有显著优势。然而，柔性电磁力加载问题和驱动线圈温升问题成为其工业化应用的关键阻碍。为此，项目采用离散柔性线圈实现电磁力柔性加载、利用耦合冷却法降低驱动线圈温升，首次提出耦合冷却式柔性电磁成形技术。基于此，拟开展电磁成形过程电磁-结构耦合分析与柔性线圈电磁力分布规律、耦合冷却过程电磁-热耦合分析与驱动线圈温升影响因素、耦合冷却式柔性电磁成形技术系统设计与装置研制、5系铝合金耦合冷却式柔性电磁成形材料性能与微观机理等研究工作。预期通过以上研究，阐明耦合冷却式柔性电磁成形技术电磁-热-结构耦合问题，揭示这一过程中材料变形宏微观机理；解决现有技术面临的两大阻碍，推动电磁成形工业化应用进程，支撑我国前沿制造产业向智能、高效和清洁的方向变革。

航空航天、汽车工业等先进制造领域亟需构建一种清洁、高效、具备国际竞争力的关键制造技术体系形成前沿突破。然而传统机械加工无法满足这一战略高度，特别是在航空航天、汽车工业等领域备受关注的轻质合金材料加工领域遭遇瓶颈。电磁成形技术作为一种特色明显、优势突出的高端制造技术，有望突破传统机械加工工艺目前所面临的瓶颈。然而，目前电磁成形技术存在两个技术难题。一是针对工件加工需求提供灵活的柔性电磁力加载；二是解决高强度紧凑型驱动线圈温升问题实现高寿命电磁成形技术。为了克服电磁成形技术中遇到的柔性电磁力加载问题与驱动线圈温升问题，项目申请人提出一种耦合冷却式柔性电磁成形技术。基于此技术，项目开展了电磁成形过程电磁-结构耦合分析与柔性线圈电磁力分布规律、耦合冷却过程电磁-热耦合分析与驱动线圈温升影响因素、耦合冷却式柔性电磁成形技术系统设计与装置研制、5系铝合金耦合冷却式柔性电磁成形材料性能与微观机理等相关研究工作。结果显示，基于离散驱动的板件电磁成形能够实现电磁力的柔性调控，为满足不同加工需求提供有效途径；采用耦合冷却式柔性电磁成形技术时板件底部极为均匀，其区域约占板件成形区域的37%，均匀成形效果极佳；耦合冷却线圈对驱动线圈的降温效果不佳，进而采用半波放电法和双板件电磁成形等方法作为新的降温方案；由于部分能量重新被存储于电容器，基于半波放电法的电磁成形工件成形效率提高了20%以上；而采用双板件电磁成形能够进一步提升板件成形效率，而效率的提高会进一步降低驱动线圈的温升。通过以上研究，阐明了耦合冷却式柔性电磁成形技术电磁-热-结构耦合问题，揭示了这一过程中材料变形宏微观机理，促进了电磁成形技术的发展。