scholarly journals FEM simulation for orthogonal cutting of Titanium-alloy considering ductile fracture to Johnson-Cook model

2016 ◽  
Vol 3 (2) ◽  
pp. 15-00536-15-00536 ◽  
Author(s):  
Makoto NIKAWA ◽  
Hiroki MORI ◽  
Yuki KITAGAWA ◽  
Masato OKADA
Keyword(s):  
Titanium Alloy ◽  
Ductile Fracture ◽  
Orthogonal Cutting ◽  
Fem Simulation ◽  
Cook Model

Inverse identification of modified Johnson–Cook model for cutting titanium alloy Ti6Al4V using firefly algorithm

2019 ◽  
Vol 234 (3) ◽  
pp. 584-599 ◽  
Author(s):  
Jinhua Zhou ◽  
Junxue Ren ◽  
Yong Jiang
Keyword(s):  
Titanium Alloy ◽  
Cutting Force ◽  
Firefly Algorithm ◽  
Orthogonal Cutting ◽  
Chip Thickness ◽  
Cutting Process ◽  
Zone Model ◽  
Serrated Chip ◽  
Titanium Alloy Ti6al4v ◽  
Cook Model

The original Johnson–Cook equation fails to describe the significant thermal softening phenomenon of flow stress in cutting process of titanium alloy Ti6Al4V. Recently, some researchers developed some modified Johnson–Cook models of Ti6Al4V by introducing some additional parameters. But effective parameter identification method is unavailable in those research works. In this work, an inverse approach is developed to determine the additional parameters. A modified Johnson–Cook model with the hyperbolic tangent function is adopted, in which four unknown parameters need to be determined. The parameter assessment is taken as an optimization process based on the unequal division parallel-sided shear zone model. Along with the measured cutting force and chip thickness, the firefly algorithm is introduced to search for the parametric optimal solution. Those four parameters are determined when the difference between the predicted and experimental effective stress at shear plane reaches its minimum. The identified constitutive model is subsequently verified by finite element simulation of orthogonal cutting process, and compared with previous different material models. With the identified modified Johnson–Cook model, the serrated chip is observed in all the simulations. A good agreement between verification experiments and simulations is achieved. An acceptable prediction accuracy with an error of 10.28% on cutting force and an error of 18.12% on chip size is achieved.

scholarly journals Analytical modelling of cutting forces in near-orthogonal cutting of titanium alloy Ti6Al4V

2014 ◽  
Vol 229 (6) ◽  
pp. 1122-1133 ◽  
Author(s):  
Yun Chen ◽  
Huaizhong Li ◽  
Jun Wang
Keyword(s):  
Titanium Alloy ◽  
Cutting Forces ◽  
Chemical Reactivity ◽  
Orthogonal Cutting ◽  
Chip Thickness ◽  
Analytical Modelling ◽  
Shear Instability ◽  
Published Data ◽  
Machining Processes ◽  
Titanium Alloy Ti6al4v

Titanium and its alloys are difficult to machine due to their high chemical reactivity with tool materials and low thermal conductivity. Chip segmentation caused by the thermoplastic instability is always observed in titanium machining processes, which leads to varied cutting forces and chip thickness, etc. This paper presents an analytical modelling approach for cutting forces in near-orthogonal cutting of titanium alloy Ti6Al4V. The catastrophic shear instability in the primary shear plane is assumed as a semi-static process. An analytical approach is used to evaluate chip thicknesses and forces in the near-orthogonal cutting process. The shear flow stress of the material is modelled by using the Johnson–Cook constitutive material law where the strain hardening, strain rate sensitivity and thermal softening behaviours are coupled. The thermal equations with non-uniform heat partitions along the tool–chip interface are solved by a finite difference method. The model prediction is verified with experimental data, where a good agreement in terms of the average cutting forces and chip thickness is shown. A comparison of the predicted temperatures with published data obtained by using the finite element method is also presented.

scholarly journals Constitutive Model and Cutting Simulation of Titanium Alloy Ti6Al4V after Heat Treatment

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4145
Author(s):  
Xiaohua Qian ◽  
Xiongying Duan
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Titanium Alloy ◽  
Orthogonal Cutting ◽  
Treatment Method ◽  
Dynamic Mechanical Properties ◽  
Ti6al4v Alloy ◽  
Stress Strain ◽  
Cutting Simulation ◽  
Titanium Alloy Ti6al4v

As a typical high specific strength and corrosion-resistant alloy, titanium alloy Ti6Al4V is widely used in the aviation, ocean, biomedical, sport, and other fields. The heat treatment method is often used to improve the material mechanical properties. To investigate the dynamic mechanical properties of titanium alloy Ti6Al4V after heat treatment, dynamic compressive experiments under high temperature and high strain rate were carried out using split Hopkinson press bar (SHPB) equipment. The stress–strain curves of Ti6Al4V alloy under different temperatures and strain rates were obtained through SHPB compressive tests. The Johnson–Cook (J–C) constitutive equation was used for expressing the stress–strain relationship of titanium alloy under large deformation. In addition, the material constants of the J–C model were fitted based on the experimental data. An orthogonal cutting simulation was performed to investigate the cutting of Ti6Al4V alloy under two different numerical calculation methods based on the established J–C model using the finite element method (FEM). The simulation results confirm that the adiabatic mode is more suitable to analyze the cutting of Ti6Al4V alloy.

scholarly journals Study on Hot Press Forming Process of Large Curvilinear Generatrix Workpiece of Ti55 High-Temperature Titanium Alloy

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 827 ◽  
Author(s):  
Fengyong Wu ◽  
Wenchen Xu ◽  
Zhongze Yang ◽  
Bin Guo ◽  
Debin Shan
Keyword(s):  
Titanium Alloy ◽  
High Temperature ◽  
Fem Simulation ◽  
Alloy Sheet ◽  
Rolled Sheet ◽  
Strain Rates ◽  
Hot Press ◽  
Forming Process ◽  
Press Forming ◽  
Hot Press Forming

In order to manufacture complex curvilinear generatrix workpieces of high-temperature titanium alloy, the hot tensile behavior of Ti55 alloy sheet was tested and the hot press forming process was investigated using Finite Element Method (FEM) simulation and experiment. The hot tensile experiments of Ti55 rolled sheet were conducted at the temperatures of 800–900 °C with the strain rates of 0.001–0.1 s−1. According to the results of hot tensile tests and microstructure evolution, the proper hot press forming parameters were determined as the temperature of 850 °C and the strain rates of 0.001–0.01 s−1. The wrinkling mechanism in the transition region was analyzed and the initial blank sheet geometry was optimized by FE simulation of hot press forming. The two-step hot press forming process was better to produce the complex sheet workpiece of Ti55 alloy than the one-step hot forming scheme, which could restrain the wrinkling trend and ensure the microstructure and mechanical properties of the hot formed workpieces.

Laser Shock Processing of Titanium Alloy Blade and FEM Simulation

2013 ◽  
Vol 456 ◽  
pp. 125-128
Author(s):  
Bing Yan ◽  
Rui Wang
Keyword(s):  
Residual Stress ◽  
Titanium Alloy ◽  
Residual Stresses ◽  
Fem Simulation ◽  
Laser Shock ◽  
Laser Shock Processing ◽  
Tc4 Titanium Alloy ◽  
Compressive Stresses ◽  
Maximum Value ◽  
Shock Processing

The aim of this article is to analyze the residual stresses field in a TC4 titanium alloy blade by laser shock processing (LSP).LSP is a new surface processing technology, it uses the laser shock wave to act on the surface of the target and form residual compressive stresses field. The ABAQUS software is applied to simulate the LSP of TC4 titanium alloy blade, and the distributions of the residual stresses field are analysed.After single LSP,the maximum value of residual stress on the surface is 309 MPa.The residual stresses on the surface increase first and then decrease.The residual stresses at the depth continue decreasing with the increase of the depth.After multiple LSP,the maximum value of residual stress on the surface is increased and plastically affected depth is increased.

scholarly journals Modeling anisotropic ductile fracture behavior of Ti-6Al-4V titanium alloy for sheet forming applications at room temperature

2020 ◽  
Vol 207 ◽  
pp. 178-195
Author(s):  
Bingtao Tang ◽  
Qingfeng Wang ◽  
Ning Guo ◽  
Xinsheng Li ◽  
Qiaoling Wang ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Ductile Fracture ◽  
Fracture Behavior ◽  
Room Temperature ◽  
Sheet Forming

scholarly journals Morphological Characteristics of Dimples of Ductile Fracture of VT23M Titanium Alloy and Identification of Dimples on Fractograms of Different Scale

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2051 ◽  
Author(s):  
Ihor Konovalenko ◽  
Pavlo Maruschak ◽  
Janette Brezinová ◽  
Jozef Brezina
Keyword(s):  
Titanium Alloy ◽  
Ductile Fracture ◽  
Digital Images ◽  
Morphological Characteristics ◽  
Automated Detection ◽  
Fracture Mechanisms ◽  
Test Results ◽  
High Quality ◽  
Quality Requirements ◽  
Shape And Size

The authors developed a method for the automated detection and calculation of quantitative parameters of dimples of ductile fracture on the digital images of fracture surfaces obtained at different scales. The processing algorithm of fractographic images was proposed, which allowed high quality recognition of the shape and size of dimples to be achieved, taking into account the morphological features of their digital images. The developed method for identifying dimples of various physical and morphological characteristics was tested on the VT23M alloy. The test results showed that the method meets the quality requirements for the automated diagnostics of fracture mechanisms of titanium alloys.

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