Finite Element Analysis of Residual Stresses in High-Speed Dry Cutting of Biodegradable Magnesium-Calcium Alloy

2012 ◽  
Author(s):  
M. Salahshoor ◽  
Y. B. Guo
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Material Behavior ◽  
Human Anatomy ◽  
Dry Cutting ◽  
Stress Profiles ◽  
Cutting Regimes

Magnesium-Calcium (Mg-Ca) alloys have become attractive biodegradable orthopedic implant biomaterials recently. Residual stresses are proven to be very influential on degradation rate of these alloys in human anatomy. Due to time and cost inhibitive reasons, development of finite element models to predict residual stress profiles under various cutting regimes is highly desirable. In this context, a finite element model of orthogonal cutting without explicit chip formation is developed by adopting plowing depth approach in order to predict process induced residual stresses in high speed dry cutting of Mg-Ca0.8 (wt %) using diamond tools. Mechanical properties of Mg-Ca0.8 alloy at high strain rates and large strains are determined using split-Hopkinson pressure bar test. Internal state variable (ISV) plasticity model is implemented to model the material behavior under cutting regimes. The residual stress evolution process and effects of plowing speed and plowing depth on residual stress profiles are studied. Residual stress measurements are performed utilizing X-ray diffraction technique for validation purposes.

FEM Simulation of the Residual Stress in the Machined Surface Layer for High-Speed Machining

2006 ◽  
Vol 315-316 ◽  
pp. 140-144 ◽  
Author(s):  
Su Yu Wang ◽  
Xing Ai ◽  
Jun Zhao ◽  
Z.J. Lv
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Surface Layer ◽  
Residual Stresses ◽  
High Speed ◽  
Metal Cutting ◽  
Orthogonal Cutting ◽  
High Speed Machining ◽  
Machined Surface ◽  
Cutting Model

An orthogonal cutting model was presented to simulate high-speed machining (HSM) process based on metal cutting theory and finite element method (FEM). The residual stresses in the machined surface layer were obtained with various cutting speeds using finite element simulation. The variations of residual stresses in the cutting direction and beneath the workpiece surface were studied. It is shown that the thermal load produced at higher cutting speed is the primary factor affecting the residual stress in the machined surface layer.

scholarly journals Semi-Empirical Prediction of Residual Stress Profiles in Machining IN718 Alloy Using Bimodal Gaussian Curve

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3864 ◽  
Author(s):  
Dong ◽  
Peng ◽  
Cheng ◽  
Xing ◽  
Tang ◽  
...  
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Residual Stresses ◽  
Statistical Model ◽  
Gaussian Function ◽  
Cutting Parameters ◽  
Residual Stress Distribution ◽  
Stress Profiles ◽  
Semi Empirical

Residual stresses are often imposed on the end-product due to mechanical and thermal loading during the machining process, influencing the distortion and fatigue life. This paper proposed an original semi-empirical method to predict the residual stress distribution along the depth direction. In the statistical model of the method, the bimodal Gaussian function was innovatively used to fit Inconel 718 alloy residual stress profiles obtained from the finite element model, achieving a great fit precision from 89.0% to 99.6%. The coefficients of the bimodal Gaussian function were regressed with cutting parameters by the random forest algorithm. The regression precision was controlled between 80% and 85% to prevent overfitting. Experiments, compromising cylindrical turning and residual stress measurements, were conducted to modify the finite element results. The finite element results were convincing after the experiment modification, ensuring the rationality of the statistical model. It turns out that predicted residual stresses are consistent with simulations and predicted data points are within the range of error bars. The max error of predicted surface residual stress (SRS) is 113.156 MPa, while the min error is 23.047 MPa. As for the maximum compressive residual stress (MCRS), the max error is 93.025 MPa, and the min error is 22.233 MPa. Considering the large residual stress value of Inconel 718, the predicted error is acceptable. According to the semi-empirical model, the influence of cutting parameters on the residual stress distribution was investigated. It shows that the cutting speed influences circumferential and axial MCRS, circumferential and axial depth of settling significantly, and thus has the most considerable influence on the residual stress distribution. Meanwhile, the depth of cut has the least impact because it only affects axial MCRS and axial depth of settling significantly.

Effect of the Welding Heat Input on Residual Stresses in Butt-Weld of High-Speed Train

2011 ◽  
Vol 337 ◽  
pp. 255-261 ◽  
Author(s):  
Zhong Yin Zhu ◽  
Peng Chen ◽  
Hong Mei Zhou ◽  
Yong Hui Zhu ◽  
Yong Hong Chen ◽  
...  
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Heat Input ◽  
High Speed ◽  
Side Wall ◽  
High Speed Train ◽  
Butt Weld ◽  
Car Body ◽  
Welding Heat Input

Abstract. This study used finite element software SYSWELD to analyze residual stresses in butt-weld between underframe and side wall of high-speed train car body. Based on the thermal-elastic-plastic theory, double ellipsoid heat source model is adopted to simulate the residual stresses under different heat input in the welded joints between underframe and side wall. The residual stresses at the surface of weld specimen were measured experimentally by using the hole-drilling method. The results of the finite element analysis were compared with experimentally measured data to evaluate the accuracy of the finite element modeling. Based on this study, a modelling procedure with reasonable accuracy was developed. The developed finite element modelling was used to study the effects of welding heat input on magnitude and distribution of welding residual stresses in butt-weld of high-speed train car body made of A6N01-T5. The results show the maximum residual stress exists in the welded seam and the adjacent-weld zone, and the residual stress value decreases gradually while the zone is farther from the weld center .Besides, With the increase of the welding heat input, the residual stress value increases gradually.

Effect Residual Stress on Material Hardness by Finite Element Simulation during the Process of High Speed Cutting

2016 ◽  
Vol 719 ◽  
pp. 23-27
Author(s):  
De Weng Tang ◽  
Zhi Feng He ◽  
Xi Jian Lv ◽  
Cong Peng
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
High Speed ◽  
Cutting Temperature ◽  
Element Model ◽  
Residual Tensile Stress ◽  
Machined Surface ◽  
High Speed Cutting ◽  
Material Hardness

Residual stresses induced during the process of high speed cutting are very critical due to safety and corrosion resistance. Based on the nonlinear finite element code DEFORM, thermodynamic couple model of residual stress was built. Effect distribution of residual stresses on three different materials physical properties of hardness are analyzed by using the finite element model during the process of high speed cutting. The results show that metal material hardness is the key factors to residual stress. When materials’ hardness is higher, residual tensile stress is easy to form on the machined surface due to high cutting temperature, such as hardened steel SKD11(HRC=62). To lower hardness material, residual compressive stress is generated on the machined surface for plastic deformation, such as softer materials 7075Al (HRC=23).

Surface Integrity of Die Material in High Speed Hard Machining, Part 2: Microhardness Variations and Residual Stresses

1999 ◽  
Vol 122 (4) ◽  
pp. 632-641 ◽  
Author(s):  
T. I. El-Wardany ◽  
H. A. Kishawy ◽  
M. A. Elbestawi
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Residual Stresses ◽  
High Speed ◽  
Residual Stress Distribution ◽  
Depth Of Cut ◽  
Hard Machining ◽  
Machined Surface ◽  
Workpiece Surface

The main objective of this paper is to investigate the quality and integrity of the surface produced during high speed hard machining (HSHM) of D2 tool steel in its hardened state (60–62 HRc). Polycrystalline Cubic Boron Nitride (PCBN) tools are used in this study. The results obtained from the micro-graphical analysis of the surface produced are presented in Part 1 of this paper. In Part 2 micro-hardness and residual stress analyses are presented. Microhardness measurements are conducted beneath the machined surface. X-ray diffraction analysis is performed to obtain the residual stress distribution beneath the surface. Analytically, a 3-D thermo-elasto-plastic finite element model is developed to predict the residual stresses induced in the workpiece surface. In the model the cutting zone is specified based on the tool condition (i.e., sharp or worn). The finite element analysis demonstrates the significant effect of the heat generated during cutting on the residual stress distribution. The results illustrate the possibility of minimizing the high tensile residual stresses produced in the workpiece surface, by selecting the appropriate depth of cut. A good correlation between the analytical and predicted residual stress is obtained. [S1087-1357(00)00804-2]

Three-Dimensional Transient Residual Stress Finite Element Analysis for a Laser Clad Surface

2003 ◽  
Author(s):  
S. Ghosh ◽  
J. Choi
Keyword(s):  
Residual Stress ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Phase Transformation ◽  
Residual Stresses ◽  
Material Behavior ◽  
Heat Transfer Analysis ◽  
Transformation Kinetics ◽  
Element Analysis ◽  
Phase Transformation Kinetics

Laser aided manufacturing process inherently includes many nonlinear and non-equilibrium transport phenomena due to non-uniform and rapid heat flow caused by the laser and the material interaction. Comprehensive understanding of the transport phenomenon and heat transfer analysis including phase transformation is essential to predict the effects of thermally induced residual stresses and distortions in deposited materials. It not only helps to improve the process but also reduces the long and cumbersome experimental route to compile sufficient data to predict the material behavior under similar loading conditions. This paper is an attempt towards a methodology of finite element analysis for the prediction of quenching related macroscopic as well as microscopic residual stress in a laser cladding process. A finite element program has been written to account for the micro-residual stress effects. The program is essentially a coupling between a preliminary estimation of temperature history of the system and the final prediction of residual stresses which also include the phase transformation kinetics of the material during its cooling. The importance of considering phase transformation effects during quenching is also verified through the comparison of the magnitudes of residual stresses with and without the inclusion of phase transformation kinetics. The FEA program for this model is a very useful tool for designing and optimizing Laseraided Direct Metal Deposition (DMD) process conditions so that products with the best internal quality and dimensional accuracy can be built.

The Influence of Cutting Depth on Residual Stresses when Orthogonal Dry Cutting GH4169 with High Speed

2012 ◽  
Vol 510 ◽  
pp. 451-454
Author(s):  
Ying Qiang Xu ◽  
Cai Hong Guo ◽  
Zu Heng Shi
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
High Speed ◽  
Virtual Work ◽  
Element Model ◽  
Depth Of Cut ◽  
Cutting Depth ◽  
Dry Cutting ◽  
Machined Surface ◽  
Machine Material

An finite element model of orthogonal dry cutting with separate line is established according to the constitutive relation of large thermo-elastic-plastic displacement and the principle of virtual work in metal plastic deformation process,. The influence of cutting depth on residual stress was simulated for materials GH4169 with high speed. The residual stresses are analyzed on the machined surface and subsurface. The result shows that tensile residual stress of the machined surface is minimum value when the cutting depth is 0.2mm. the deeper is the depth of cut, the large the augmentation of compressive stress on the subsurface, which proves foundation for cutting process of dry-machined difficult-to-machine material with high speed and make it more efficiently to control the integrity of the machined surface.

A Finite Element Analysis Based Compliance Method Coupled With Wet Etching to Determine Residual Stress in High Speed Milling

2005 ◽  
Author(s):  
S. C. Ammula ◽  
Y. B. Guo ◽  
M. E. Barkey
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
High Speed ◽  
Wet Etching ◽  
Cutting Conditions ◽  
Traditional Methods ◽  
New Approach ◽  
High Speed Milling ◽  
Compliance Function

High speed milling (HSM) is widely used in automotive and aerospace industries in fabricating mechanical components from high strength aluminum and other alloys due to high productivity and good surface finish. HSM induced residual stresses may significantly impact the fatigue life and corrosion resistance of the machined components. Traditional methods of residual stress (RS) measurement, such as hole drilling, X-ray diffraction, and neutron diffraction, are very time consuming and expensive, especially for the shallow subsurface (usually <100 μm) of a machined component. The compliance method provides a convenient alternative to these approaches to determine the residual stress distributions in the subsurface. However, the compliance method using wire EDM is prone to experimental errors. In addition, the traditional approach to calculate compliance function is very complex. This paper presents a new wet etching approach to obtain strains as a function of slot depth introduced in the subsurface. The strain readings were collected from a strain gauge mounted on the specimen surface near the slot edge. The compliance function can be conveniently calculated by simulating slot cutting using the finite element method via a Legendre polynomial subroutine as the applied load. These calculated compliance functions and measured strain values at different depths were used as inputs into a program to calculate residual stress. This leads to much a faster and less expensive method of determining residual stresses when compared with the traditional methods of residual stress determination. The capability of this new approach was demonstrated by high speed milling 6061-T651 and 7050-T7451 aluminum alloys. A design of experiment (DOE) method was adopted to conduct fifty-four cutting conditions with three levels of cutting speed, feed rate, and depth of cut. Residual stress profiles with twelve data points with spatial resolution as small as 1 μm in the subsurface were then obtained using this new approach. Residual stress sensitivity to cutting conditions was investigated. In addition, subsurface microstructure and microhardness were characterized.

Local Stress Variations at Bead Interruptions in Austenitic Multi-Pass Groove Welds

2009 ◽  
Author(s):  
Christopher M. Gill ◽  
Paul Hurrell ◽  
John Francis ◽  
Mark Turski
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Good Practice ◽  
304 Stainless Steel ◽  
Stress Profile ◽  
Stress Distributions ◽  
Fe Modelling ◽  
Stress Profiles

This paper presents finite element analyses of residual stress in an austenitic multi-pass groove weld. The aim was to establish the effect upon the residual stress of stop-start interruptions during the deposition of weld beads. Comparison of measured residual stress profiles with the residual stress distributions predicted by finite element (FE) modelling aimed to validate the FE method for predicting residual stresses around stop-start features. This paper presents a comparison of measured and modelled residual stress distributions in a series of simple welded 304 stainless steel plates. The plates were machined with a v-groove designed to be filled using eight weld passes. Samples which included interrupted weld beads contained two stop-start features in the fifth pass. In the first feature the welding power was ramped down over 15 seconds; this represented normal welding good practice. The second feature investigated was an abrupt stop, where the welding power was removed instantaneously; this represented an extreme stop. Three welded plates were considered. One contained five weld passes, such that the final pass contained stop-start features and resulted in partially filling the weld groove. Two welds plates each containing eight passes have also been considered; one contained stop-start features in the fifth pass and the other contained no stop-start features. This allowed a comparison of the effect of stop-start features and the effect that subsequent beads have upon any perturbations in the residual stresses produced. Residual stress measurements have been performed using neutron diffraction. 3D weld modelling has been carried out using VFT and the Abaqus finite element package. Results from the welding FE analyses were compared with the neutron diffraction measurements. Good agreement between the modelled and measured residual stresses is achieved in the uninterrupted 8-pass sample and after deposition of the bead containing stop-start features in the 5-pass sample. Following deposition of subseqeunt beads perturbations in the residual stress profile are retained in the neutron diffraction measurements, but all perturbations are removed from the residual stress profiles predicted using both VFT and Sysweld. This work suggests that modelling welding stop-start features is only necessary in the final weld capping passes, if residual stresses over a short length scale are of interest.

Cutting Mechanics of High Speed Dry Machining of Magnesium-Calcium Biomedical Alloy Using Internal State Variable Plasticity Model

2011 ◽  
Author(s):  
M. Salahshoor ◽  
Y. B. Guo
Keyword(s):  
Mechanical Properties ◽  
Chip Formation ◽  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Internal State ◽  
Material Behavior ◽  
Internal State Variable ◽  
Plasticity Model ◽  
Dry Cutting ◽  
State Variable

Magnesium-Calcium (MgCa) alloys have become attractive orthopedic biomaterials due to their biodegradability, biocompatibility, and congruent mechanical properties with bone tissues. However, process mechanics of machining biomedical MgCa alloys is poorly understood. Mechanical properties of the biomedical magnesium alloy at high strain rates and large strains are determined by using the split-Hopkinson pressure bar testing method. Internal state variable (ISV) plasticity model is implemented to understand the dynamic material behavior under cutting conditions. A finite element simulation model has been developed to study the chip formation during high speed dry cutting of MgCa0.8 (wt %) alloy. Continuous chip formation predicted by the FE simulation is verified by high speed dry face milling of MgCa0.8 using polycrystalline diamond (PCD) inserts. Chip ignition is known as the most hazardous aspect of machining Mg alloys. The predicted temperature distributions may well explain the reason for machining safety of high-speed dry cutting of MgCa0.8 alloy.

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