船舶大曲率不可展曲板的力-热协同变形与工艺规划研究

The undevelopable surfaces are widely used in shipbuilding industry. However, this curved surface is fabricated through the thermal forming based on the experience. This proposal put forward a novel forming process based on mechanical and thermal forming of undevelopable curved plates with large curvatures, which means that the undevelopable surface is formed by laser line heating from the single-curved shape fabricated by mechanical forming. Since the mechanical and thermal forming method involves multiple solutions, the study of the strain optimization and relationship of in-pane and out-of-plane strains are carried out to formulate the process planning of mechanical and thermal forming..This project investigates the mechanical and thermal forming of double-curved surface based on the reverse and forward method using theoretical analysis, numerical simulation and experiments. The strain energy optimization during the surface development is established, which can give unique solution from the double-curved shape to single-curved shape. Based on the characterization of the in-plane and out-of-plane strains, the direction of the comprehensive strain can be determined, which helps the laser scanning path planned. The deformation behavior of the plate heated by the laser beam under multiple constraints is investigated, which can determine the heating parameters (laser power and scan velocity) for each heating line based on the database. This proposed method can provide an effective and controllable way for forming of the curved plate. .Through this project, the mechanics theory for the development of the double-curved shape and the method for the comprehensive strain of in-plane and out-of-plane strains can be established, which enriches the basic theory in compound forming using multiple energies. The indirectly coupled mechanical and thermal forming method can realize the digital and automated process in shipbuilding industry. This research will be of great academic and industrial value.

针对船舶大曲率不可展曲板小批量、多规格的成形需求，基于平板-单曲率板-不可展曲板的成形工艺流程，采用逆向反求与正向求解的研究方法，开展力-热协同成形的应变反求优化与综合表征研究，解决机械-轨迹加热成形存在的曲面展开和路径规划多解问题，形成力-热间接耦合成形的工艺方法，突破不可展曲板成形依赖经验的技术瓶颈。建立不可展曲面展开过程中的应变优化模型，实现不可展曲板的唯一展开,形成机械成形工艺方法；探索板内和板外应变综合表征方法，实现加热轨迹在曲面上的规划，通过多约束加热变形行为研究，完成加热参数的选取，形成轨迹加热的工艺方法；基于机械-轨迹加热协同成形工艺的优化，实现不可展曲板的高效可控成形。通过本项目研究，可以建立不可展曲面板展开的力学理论和曲板应变的综合方法，充实复合能量场成形的基础理论；形成的力-热间接耦合成形工艺方法，可以实现舰船全流程的数字化和自动化制造，具有重要的学术意义和产业价值。

船舶外板形状包含多种不可展曲面（马鞍形、扭曲形和帆形等），属于典型的小批量、多品种生产模式。传统机械冷成形（冲压、辊压、多点成形等）存在材料开裂和褶皱等成形缺陷。而轨迹加热成形属于热累积无模成形技术，但单次扫描变形量有限，成形效率较低。因此本项目采用机械-轨迹加热协同成形方式，通过高效的机械加工方法将平板成形为接近目标不可展曲板的单曲率曲面，再利用柔性的轨迹加热方法完成不可展几何特征成形。.本项目建立了不可展曲面展开过程中的应变优化模型，实现了不可展曲板的唯一展开,形成机械成形工艺方法；探索了板内和板外应变综合表征方法，实现了加热轨迹在曲面上的规划，通过多约束加热变形行为研究，完成加热参数的选取，形成了轨迹加热的工艺方法；基于机械-轨迹加热协同成形工艺的优化，实现了不可展曲板的可控成形。.本项目基于平板-单曲率板-不可展曲板的成形工艺流程，采用逆向反求与正向求解的研究方法，开展力-热协同成形的应变反求优化与综合表征研究，解决机械-轨迹加热成形存在的曲面展开和路径规划多解问题，形成力-热成形的工艺方法，突破不可展曲板成形依赖经验的技术瓶颈。实现了DH36、AH40等高强钢大尺度（4 m×1.25 m×8 mm）船用板材帆型面的成形，曲面精度达到国军标规定要求。相关研究成果为装备预研船舶重工联合基金项目“智能曲板激光成型技术”（2019-2020）的成功申报提供了研究基础，也为与中国航天科工三院的合作项目“钛合金翼舵类蒙皮激光热弯曲快速成形技术研究”（2021-2022）提供了技术支撑。.本项目建立的不可展曲面板展开力学理论和曲板应变的综合方法，充实了复合能量场成形的基础理论；形成的复合成形工艺方法，可以实现舰船全流程的数字化和自动化制造，具有重要的学术意义和产业价值。以第一作者/通讯作者发表SCI论文2篇，中文核心论文2篇，申请发明专利1项，指导硕士学位论文2篇（均获学院优秀硕士学位论文）。