基于正交切削理论的航空钛合金切削加工本构模型构建

Construction of material constitutive model during cutting process for aeronautical titanium alloy based on orthogonal cutting theory

为弥补现有航空钛合金切削加工本构模型研究的不足,提出基于正交切削理论的材料本构模型构建方法。根据正交切削理论建立剪切区内应力、应变、应变率、温度以及二维切削力的数学模型,开发以剪切区长度和厚度比值为迭代变量的建模技术,结合动态压缩力学性能实验(SHPB实验)和直角铣削实验,通过对各变形参数的数学求解,建立航空钛合金切削加工本构模型。在此基础上,进行材料本构模型的分析和实验验证。结果表明:航空钛合金材料在切削加工中具有明显的应变硬化特性、温度敏感特性和应变率敏感特性;钛合金随着应变率的增大,流动应力的增量逐渐减小,材料的应变率敏感性降低。

To make up the shortcoming of the current researches in material constitutive model during cutting process, a construction method of material constitutive model based on orthogonal cutting theory was presented. According to the orthonal cutting theory, the mathematic model of stress, strain, strain rate and temperature in shear zone, as well as the two-dimensional cutting force, was established. The constrution technology of material constitutive model by taking the ratio of length to depth in shear zone as an iterative variable was developed. With the split Hopkinson pressure bar （SHPB） compression experiment and orthogonal cutting experiment, the material deformation physical quantities were solved and the material constitutive model was established. The prediction values of material constitutive model were compared with the cutting experiment ones, and they are found to be in good agreement. The results show that titanium alloy material has obvious strain hardening characteristic, temperature sensitivity characteristic and strain rate sensitivity characteristic during cutting process. And with the increase of strain rate, the flow stress increment decreases, and the strain rate sensitivity characteristic decreases.