【作者】 蔡旺；

【导师】 杨合；

【作者基本信息】 西北工业大学 ， 材料加工工程， 2002， 硕士

【摘要】 叶片是航空发动机中一类量大面广的重要零件，精锻是叶片锻造的发展趋势。叶片精锻过程属于高温大变形过程，坯料与模具和环境之间存在着热交换，同时塑性变形功以及坯料和模具间的摩擦功不断转化为热能，其结果促使坯料内的温度场不断发生变化，进而影响到坯料的变形行为，并进一步影响锻件的微观组织及机械性能。因此采用三维热力耦合有限元数值模拟技术，研究叶片精锻成形规律，对制定叶片精锻工艺以及发展叶片精锻技术具有重要的理论意义和实用价值。本文的主要研究内容和结果如下： 对金属体积成形过程三维刚粘塑性热力耦合有限元模拟中的关键技术问题进行了研究，特别是针对减速因子β的选取，首次建立了适用于三维复杂成形过程刚粘塑性罚函数法有限元三次因子法的计算公式，并结合进退搜索法提出了改进的三次因子快速算法，提高了模拟计算效率和稳定性。 以叶片锻造三维刚粘塑性有限元模拟分析系统3D-PFS为平台，发展了面向叶片精锻过程的三维刚粘塑性热力耦合有限元模拟分析系统3D-CTM(3-Dimensional Coupled Thermo-Mechanical Forming Simulation)。对圆柱体镦粗过程的应用表明，所开发的系统是可靠的。 针对单榫头叶片，建立了符合实际的三维刚粘塑性热力耦合有限元模型；利用3D-CTM系统进行了三维热力耦合模拟研究，揭示了单榫头叶片精锻成形规律，指出了温度在锻造过程中的重要作用；获得了不同变形速度、摩擦因子、模具温度和坯料锻造温度对单榫头叶片精锻过程的影响规律。 采用3D-CTM系统并与适用于TC4钛合金锻造晶粒尺寸预测模型相结合，对热力耦合作用下单榫头叶片精锻过程的晶粒尺寸进行了计算，获得了不同变形阶段、变形速度、摩擦因子和模具温度下的晶粒尺寸分布，分析了不同工艺参数对其晶粒尺寸的影响规律。更多还原

【Abstract】 A blade is one of the most important mechanical components in an aero-engine. Precision forging of blade is a tendency for development of blade-forging technology. However, precision forging process of blade is high temperature and large deformation, there is heat transfer on billet - die interface, simultaneously plastic work and frictional work turn to heat, all these factors make temperature filed of billet continually change, the change of temperature field will affect deformation behavior of billet, furthermore affect the mechanical capability and microstructure of blade. Therefore, it is important to using 3D coupled thermo-mechanical FEM numerical simulation to research on precision forging process of blade for the optimization of precision forging technology and the development of its precision forging. A brief introduction to the project and its main results are as follows:The key technical problems of 3D coupled thermo-mechanical rigid-viscoplastic FEM simulation of blade forging process are studied systematically. Formulations to determine relaxation factor β are firstly established for rigid viscoplastic FEM adopting penalty function method, an improved cubic factor rapid algorithm derived from these formulations is proposed by combining with the advantage of advance and retreat search method. The results show that the algorithm can obviously improve convergence stability and reduce iteration steps.Based on 3D-PFS (3D Plastic Forming Simulation) system developed in our laboratory, a simulation system, 3D-CTM (3-Dimensional Coupled Thermo-mechanical Forming Simulation), for precision forging of the blade is developed. By applying 3D-CTM to cylinder upsetting, the results show that the system is reliable.A 3D thermal-mechanical coupling FEM simulation model corresponding to reality is set up for the precision forging process of the blade with tenon. By using the 3D-CTM system, the law of the blade precision forging process is revealed, and an important function of temperature in forming process is indicated. The influence ofdifferent deforming velocity, friction factor, die temperature and forging temperature of billet on the forming laws of precision forging process of blade is obtained.Based on a model which can be used to predict grain size of forging TC4 titanium alloy, gram size of the precision forging process of blade with tenon is computed by 3D-CTM system with different deformation parameters (deforming phases, velocity, friction factor and die temperature), and the influence of these deformation technological parameters on grain size is studied.更多还原