A constitutive model for Ti6Al4V considering the state of stress and strain rate effects. (October 2019)

• Record Type: Journal Article
• Authors: Cheng, Wenyu; Outeiro, Jose; Costes, Jean-Philippe; M'Saoubi, Rachid; Karaouni, Habib; Astakhov, Viktor
• Is Part Of: Mechanics of materials. Volume 137(2019)
• Publication Date: 2019-10
• Subjects: Constitutive behavior -- Mechanical testing -- Fracture mechanisms -- Manufacturing processes; Strength of materials -- Periodicals; Mechanics, Applied -- Periodicals; Résistance des matériaux -- Périodiques; Mécanique appliquée -- Périodiques; Mechanics, Applied; Strength of materials; Periodicals; Electronic journals; 620.11
• DOI: 10.1016/j.mechmat.2019.103103
• Languages: English
• ISSNs: 0167-6636

Abstract

Highlights: A constitutive model including the most relevant parameters affecting the mechanical behavior (plasticity and damage) of Ti6Al4V titanium alloy in metal cutting (i.e. the state of stress and the strain-rate) is proposed. Special specimens' design to generate a wide range of states of stress (i.e. triaxiality and Lode angle) in mechanical testing, which are representative of metal cutting process. Higher accuracy of the determination of the coefficients of the constitutive model using the developed optimization-based procedure. The accuracy of the proposed model to represented mechanical behavior of the Ti6Al4V titanium alloy under different state of stresses was confirmed when its results were compared with those obtained experimentally. Abstract: The predictability of manufacturing process simulation is highly dependent on the accuracy of the constitutive model to describe the mechanical behavior of the work material. The model should consider the most relevant parameters affecting this behavior. In this study, a constitutive model for Ti6Al4V titanium alloy is proposed that considers both material plasticity and damage. It includes the effects of strain hardening, strain-rate and the state of stress to represent the mechanical behavior of Ti6Al4V titanium alloy in metal cutting simulation. To generate states of stress and strain rates representative of this process, mechanical tests were performed using a specific experimental setup. This included a specimen geometry designed to generate different states of stress, as well as a digital image correlation technique to obtain the strains during the mechanical tests. For the determination of the coefficients of the constitutive model, the yield stress and fracture locus obtained from these tests were used in an optimization-based procedure. To verify the accuracy of the proposed constitutive model to represent the mechanical behavior of the Ti6Al4V alloy under different states of stress, force–displacement curves obtained using this model and the Johnson-Cook model are compared with the curves obtained experimentally. Graphical abstract: Image, graphical abstract