水室封头作为核电蒸汽发生器等设备的关键部件，是蒸汽发生器与核反应压力容器等其他部件的接口，其形状复杂，加工难度非常大，研制水室封头加工专用数控机床，攻克水室封头高效加工技术难题，是有效推进我国第三代核电装备系列化、批量化生产的重要保障。目前，国内外常采用大型立车、落地铣镗床等通用机床结合变位机来实现水室封头的加工，该方式生产组织环节多、生产周期长，加工与检测设备及辅具制备耗费量大，精度难以保证。针对以上问题，本文提出设计水室封头专用数控机床的高效加工解决方案，并针对机床关键件存在的共性问题，以提高机床零部件综合性能为目标，开展关键件的结构优化设计及滑枕挠曲变形补偿研究。主要研究成果如下： (1)提出核电水室封头专用数控机床高效加工方案。针对水室封头加工工艺需求及现有加工过程中存在的问题，提出水室封头加工专用数控机床的整机结构布局方案；通过有限元分析得到整机的静动态特性，进而确定了机床的薄弱环节及横梁等关键件的结构优化空间。 (2)提出基于功能截面分解的横梁多工况拓扑优化方法。针对横梁结构的轻量化需求及传统拓扑优化方法存在的问题，建立横梁多工况刚度评价函数，根据横梁变形量确定各工况权重因子，分别对两个主要承载的功能截面进行二维拓扑优化分析，综合二维功能截面分析结果及初始模型优化结果，完成横梁拓扑结构改进，实现横梁的轻量化设计。 (3)提出考虑疲劳寿命的横梁结构尺寸优化设计方法。在横梁拓扑优化基础上，为了确保横梁的可靠性，推导非对称循环下材料的力学参数和寿命之间的对应关系，通过有限元分析计算横梁可靠度为99.9％时的寿命，进而推导出部件可靠度为99.9％时对应寿命的最大应力，并以该最大应力为约束条件进行尺寸优化研究，在保证横梁可靠性基础上进一步实现了轻量化。 (4)提出基于TRIZ理论的A轴组件结构改进设计与优化方法。针对机床A轴组件刚度不足的问题，综合利用力学、机械设计、制造工艺学等理论知识，基于TRIZ理论寻找能显著增强A轴组件局部刚度的改进方案，并采用尺寸优化进一步提高其刚度，缩小结合面缝隙，使其满足行业要求。 (5)提出可摆动滑枕挠曲变形补偿方法。针对可摆动滑枕的挠曲变形问题，建立滑枕在行程和摆角双重因素影响下的滑枕变形力学模型和补偿力学模型，通过仿真分析，得出滑枕挠曲变形量与其行程和摆角之间的关系曲线，提出可摆动滑枕挠曲变形补偿方法，计算安装附件情况下滑枕变形补偿力，并设计相应的补偿系统。 关键词：核电水室封头；数控机床；结构优化；疲劳寿命；TRIZ；变形补偿

 As the key components of nuclear power steam generator and other equipments, water chamber head is the interface between steam generator and other components such as nuclear reaction pressure vessel, with the complex shape, it is very difficult to process. Overcoming the technical difficulties of efficient processing and developing a special numerical control machine for water chamber head processing is the guarantee for effectively promoting the serialization and batch production of the third generation nuclear power equipment in China. At present, large vertical lathe, floor milling and boring machine and other general machine tools are often used in combination with positioner to realize the processing of water chamber head at home and abroad. It has many organizational links and long production cycle, the consumption of processing and testing equipment and auxiliary equipment is very high, and the accuracy is difficult to guarantee. For the problems, an efficient processing solution of NC machine tool for water chamber head is proposed in this dissertation. Aiming at the common problems, structural optimization of key parts and deflection compensation of slider are studied to improve the comprehensive performance. The main research results are as follows: (1)A high-efficiency NC machine tool for the nuclear power water chamber head is proposed. Aiming at process requirement and existing problems in the processing of water chamber head, structure layout of the NC machine tool for water chamber head is put forward. Static and dynamic characteristics of the machine are obtained, the optimization space of the key parts such as the cross beam and the weak links of the machine tool are determined using finite element analysis, which lays a foundation for the structural optimization of the key parts such as the cross beam and the deflection compensation for the ram. (2)A cross-beam under multiple load cases topology optimization method based on functional section decomposition is proposed. Aiming at the lightweight requirement of cross-beam structure and problems existing in traditional topology optimization methods, the multi-condition stiffness evaluation function of beam is established, the weight factors of each working condition are determined according to the deformation of the beam, the two main load bearing functional sections are analyzed by two dimensional topological optimization, combining the two-dimensional functional cross section analysis and initial model optimization, the topology structure of cross-beam is improved, and the lightweight design of cross-beam is realized. (3)A size optimization method of cross beam considering fatigue life is proposed. Based on topological optimization of the beam, the corresponding relationship between the mechanical parameters and the life of the material under the asymmetric cycle is deduced to ensure beam reliability. The life of the beam with 99.9% reliability is calculated by finite element analysis, and then the maximum stress of the corresponding life when the reliability of the component is 99.9% is deduced. The dimension optimization research is carried out with the maximum stress as the constraint condition. On the basis of guaranteeing the reliability of the beam, the lightweight is further realized. (4)An innovative design and optimization method of A-axis component structure based on TRIZ theory is proposed. Aiming at the problem of insufficient stiffness of A-axis assembly, this thesis synthetically utilizes the theoretical knowledge of mechanics, mechanical design, manufacturing technology and so on. Based on TRIZ theory, an improved scheme which can significantly enhance the local stiffness of A-axis assembly is found, and size optimization is adopted to further improve its stiffness, narrow the gap of joint surface, so as to meet the requirements of the industry. (5)A deflection compensation method of swinging ram is proposed. Aiming at the problem of the swing ram deflection, the mechanical model of ram deflection and compensation under the influence of both stroke and swing angle is established. Through simulation analysis, the curve of the relationship between ram deflection and its stroke and swing angle is obtained. The deflection compensation method of the swing ram is put forward, deflection compensation force of ram with attachment is obtained and the corresponding compensation system is designed. Keywords: nuclear water chamber head; NC machine tool; sturctural optimization; fatigue life; TRIZ; deflection compensation