Finite element modeling of machining aims for guidance in the choice of the cutting parameters and for the comprehension of the involved phenomena. The modeling of the behavior of the machined material is a key parameter to develop a realistic model. It is nowadays still extremely difficult to acquire experimental data on the material flow stress due to the extreme conditions encountered during machining. Many constitutive models are found in the literature and there is a lack of objective information to choose the best suited for a given application. Four empirical constitutive models are used in this paper to represent the Ti6Al4V titanium alloy during an orthogonal cutting operation. All of them are based on the well-known Johnson-Cook model. The results of this study show that the influence of the constitutive model on the chip morphology and on the cutting force is high and that the strain softening phenomenon should be taken into account to produce a segmented (or saw-toothed) chip as it is experimentally observed. For the cutting conditions adopted, adding damage properties in the chip is moreover required to obtain a morphology close to the experimental reference. All these elements allow to get a reliable numerical model able to reproduce cutting forces and chip morphology (either continuous or segmented) for various cutting conditions.

加工的有限元建模旨在指导选择切削参数和理解所涉及的现象。加工材料的行为建模是开发实际模型的关键参数。由于在加工过程中遇到的极端条件，如今仍然非常难以获得有关材料流动应力的实验数据。在文献中发现了许多本构模型，并且缺乏客观的信息来选择最适合给定应用的模型。本文使用四个经验本构模型来表示Ti6Al4V钛合金在正交切削过程中。所有这些都是基于著名的Johnson-Cook模型。这项研究的结果表明，本构模型对切屑形态和切削力的影响很大，并且应考虑到应变软化现象，以产生切段（或锯齿状）切屑，因为它是实验性的观察到的。对于采用的切削条件，还需要在切屑中增加损伤特性，以获得接近实验参考的形态。所有这些元素都允许获得可靠的数值模型，该模型能够针对各种切削条件再现切削力和切屑形态（连续或分段）。