Finite Element Modeling of Burnishing and the Effects of Process Parameters on Surface Integrity of Orthopedic Implants

2011 ◽  
Author(s):  
M. Salahshoor ◽  
Y. B. Guo
Keyword(s):  
Surface Roughness ◽  
Residual Stresses ◽  
Process Parameters ◽  
Surface Integrity ◽  
Internal State ◽  
Material Model ◽  
Orthopedic Implants ◽  
Fe Model ◽  
Dynamic Mechanical Behavior ◽  
Layer I

Hydrostatic burnishing is mainly a ceramic ball supported by a pressurized cushion of hydraulic oil and pushed against the workpiece surface. As the ball rolls along the surface it produces a unique combination of three physical effects in the surface layer: i) work hardening and increased hardness, ii) burnishing and decreased roughness, and iii) increased compressive residual stresses. This process has gained an increasingly great attention in automotive, aerospace, and especially medical device manufacturing industries. However, most of the research in hydrostatic burnishing has been performed experimentally and there is still lack of numerical studies providing fundamental understanding of the mechanics and the way process parameters interact with surface integrity characteristics particularly surface roughness and residual stresses. Understanding the correlation between process parameters and surface integrity is critical in efficiently adjusting the surface integrity in order to achieve proper biodegradation rate in human body after implantation. In this study, the dynamic mechanical behavior of the material is simulated using internal state variable (ISV) plasticity model. A semi-infinite, two-dimensional, plane strain FE model is developed and the ISV material model is incorporated into it using a user defined material subroutine. The effects of burnishing pressure and feed on surface roughness and residual stresses are investigated. The simulation results are validated with experimental measurements of residual stresses and surface roughness.

scholarly journals Influence of High-Productivity Process Parameters on the Surface Quality and Residual Stress State of AISI 316L Components Produced by Directed Energy Deposition

2021 ◽  
Author(s):  
Gabriele Piscopo ◽  
Alessandro Salmi ◽  
Eleonora Atzeni
Keyword(s):  
Surface Roughness ◽  
Residual Stresses ◽  
Surface Quality ◽  
Process Parameters ◽  
Energy Deposition ◽  
Industrial Applications ◽  
High Productivity ◽  
Directed Energy Deposition ◽  
Productivity Process ◽  
Directed Energy

AbstractThe production of large components is one of the most powerful applications of laser powder-directed energy deposition (LP-DED) processes. High productivity could be achieved, when focusing on industrial applications, by selecting the proper process parameters. However, it is of crucial importance to understand the strategies that are necessary to increase productivity while maintaining the overall part quality and minimizing the need for post-processing. In this paper, an analysis of the dimensional deviations, surface roughness and subsurface residual stresses of samples produced by LP-DED is described as a function of the applied energy input. The aim of this work is to analyze the effects of high-productivity process parameters on the surface quality and the mechanical characteristics of the samples. The obtained results show that the analyzed process parameters affect the dimensional deviations and the residual stresses, but have a very little influence on surface roughness, which is instead dominated by the presence of unmelted particles.

scholarly journals Numerical Study on Surface Roughness Measurement Based on Nonlinear Ultrasonics in Through-Transmission and Pulse-Echo Modes

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4855
Author(s):  
Maodan Yuan ◽  
Anbang Dai ◽  
Lin Liao ◽  
Yan Chen ◽  
Xuanrong Ji
Keyword(s):  
Surface Roughness ◽  
Numerical Study ◽  
Material Model ◽  
Nonlinearity Parameter ◽  
Fe Model ◽  
Roughness Measurement ◽  
Monitoring Method ◽  
Surface Roughness Measurement ◽  
Nonlinear Ultrasonics ◽  
Pulse Echo

Ultrasonic is one of the well-known methods for surface roughness measurement, but small roughness will only lead to a subtle variation of transmission or reflection. To explore sensitive techniques for surfaces with small roughness, nonlinear ultrasonic measurement in through-transmission and pulse-echo modes was proposed and studied based on an effective unit-cell finite element (FE) model. Higher harmonic generation in solids was realized by applying the Murnaghan hyperelastic material model. This FE model was verified by comparing the absolute value of the nonlinearity parameter with the analytical solution. Then, random surfaces with different roughness values ranging from 0 μm to 200 μm were repeatedly generated and studied in the two modes. The through-transmission mode is very suitable to measure the surfaces with roughness as small as 3% of the wavelength. The pulse-echo mode is sensitive and effective to measure the surface roughness ranging from 0.78% to 5.47% of the wavelength. This study offers a potential nondestructive testing and monitoring method for the interfaces or inner surfaces of the in-service structures.

Analysis and Prediction of Surface Integrity in Machining: A Review

2014 ◽  
Vol 610 ◽  
pp. 1002-1020 ◽  
Author(s):  
Yuan Gao ◽  
Xin Huang ◽  
Ming Jie Lin ◽  
Zheng Guo Wang ◽  
Rong Lei Sun
Keyword(s):  
Surface Roughness ◽  
Grain Size ◽  
Residual Stresses ◽  
Surface Integrity ◽  
Material Properties ◽  
Cutting Parameters ◽  
Mechanical Parameters ◽  
Factors Affecting ◽  
Grain Size And Shape

Surface integrity is widely used for evaluating the quality of machined components. It has a set of various parameters which can be grouped as: (a) topography parameters such as surface roughness, textures and waviness (b) mechanical parameters such as residual stresses and hardness, and (c) metallurgical state such as microstructure, phase transformation, grain size and shape, inclusions etc. Surface roughness and residual stresses are among the most significant parameters of surface integrity, so that it is worth investigating them particularly. Many factors affect the surface integrity of machined components, including cutting parameters, tool parameters, material properties and vibrations. We can make prediction and optimization for surface integrity by taking advantage of these factors. This paper reviews previous studies and gives a comprehensive summary of surface integrity in the following order: introduction of surface integrity, main parameters of surface integrity, factors affecting surface integrity, prediction and optimization for surface integrity.

Surface Integrity of Biodegradable Magnesium-Calcium (Mg-Ca) Alloy by Low Plasticity Burnishing

2010 ◽  
Author(s):  
M. Salahshoor ◽  
Y. B. Guo
Keyword(s):  
Surface Roughness ◽  
Residual Stresses ◽  
Surface Integrity ◽  
Bulk Material ◽  
Large Diameter ◽  
Biological Response ◽  
The Body ◽  
Low Plasticity Burnishing ◽  
Sever Plastic Deformation ◽  
Biodegradable Magnesium

When a device is implanted into the body, into either hard or soft tissue, the body will respond. While the bulk material of the device is often important for integrity and mechanical success, the device surface is at the interface with biology. Major effort has been spent modifying a biomaterial surface in order to elicit or inhibit a biological response. Metallic biodegradable Magnesium-Calcium (Mg-Ca) alloys have attracted an increased attention for orthopedic fixation applications. This research focuses on low plasticity burnishing (LPB) as a novel surface modification technique that is added to the surface to control biodegradation as a biological response. The effects of burnishing pressure as an important process parameter on surface integrity characteristics such as surface roughness, surface topography, and residual stresses are investigated. Burnished surface roughness is smaller than the machined ones. However, some amount of waviness is observed which might be due to large diameter of the burnishing ball and sever plastic deformation. High compressive residual stresses are measured on the burnished surface.

Effect of Coating Process Parameters on the Development of Residual Stresses in Ceramic Coatings

2019 ◽  
Author(s):  
Ali Gadelmoula ◽  
Khaled Al-Athel
Keyword(s):  
Residual Stresses ◽  
Process Parameters ◽  
Elevated Temperatures ◽  
Ceramic Coatings ◽  
Interface Roughness ◽  
Fe Model ◽  
Computational Framework ◽  
Scientists And Engineers ◽  
Coating Layers

Abstract Ceramic coatings are widely used in many engineering applications, especially applications related to components operating at elevated temperatures. One of the main issues relates to ceramic coatings is the development of residual stresses due to quenching and the thermal mismatch between the deposited coating layers and the substrate. In this work, a computational framework is developed to investigate the effect of various process parameters on the development of the residual stresses. The geometry of the coating layers and the interface roughness between the layers is first generated using SimCoat, a Monte Carlo based statistical algorithm that determines the effect of process parameters (droplet size, spraying speed, etc.) on the characteristics of the developed coating (coating thickness, porosity, etc.). An in-house code is used to convert the statistical data into a finite element (FE) model. Various FE models are generated with different process parameters, and the development of residual stresses is compared between them. The developed framework can be used by material scientists and engineers to predict the quality of the coating and optimize the process parameters to any specific application.

Taguchi Grey Relational Approach for Optimizing Process Parameters of Laser Peening on Titanium Alloy to Induce Enhanced Compressive Stress based on Finite Element Simulation

2020 ◽  
Vol 19 (02) ◽  
pp. 365-387
Author(s):  
G. Ranjith Kumar ◽  
G. Rajyalakshmi
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Compressive Stress ◽  
Process Parameters ◽  
Surface Deformation ◽  
Material Behavior ◽  
Laser Spot ◽  
Fatigue Properties ◽  
Fe Model ◽  
Grey Relational

Laser Shock Peening (LSP) turned out to be the most efficient surface engineering process for advanced materials to induce beneficial deep compressive residual stress which helps in improving mechanical, fatigue properties and surface damage resistance. But, analyzing the nonuniform distribution of residual stresses in the treated sample with X-ray diffraction (XRD) is much time taking and a costly process. This problem can be resolved with LSP finite element numerical simulation model which is feasible with the realistic experimental process. The FE model allows the user to control the laser parameters in order to achieve the optimal level of all controllable parameters. This study is intended to analyze and optimize the influence of laser processing parameters that assists in inducing the residual compressive stress with minimal surface deformation. A Ti6Al4V material model with Johnson–Cook’s visco-elastic–plastic material behavior law is prepared for LSP simulation. Gaussian pressure profile is utilized for uniform loading of the targeted zone for the proposed model. Taguchi Grey Relational Analysis (TGRA) with L27 orthogonal array is applied to LSP simulation, and the results were analyzed with consideration of multiple response measures. It is noted that surface deformation is increased with the rise in a number of laser shots and pressure pulse duration. Maximum compressive residual stresses are falling for higher levels of laser spot diameter, laser spot overlap and laser power density. The correlation is observed between the FE simulation and the published results. The optimal set of process parameters are obtained for improving the LSP on Ti alloys.

Influence of the Metallurgical Transformation Induced by Grinding on the Residual Stresses Computation

2012 ◽  
Vol 565 ◽  
pp. 196-201 ◽  
Author(s):  
Sawsen Youssef ◽  
Haifa Sallem ◽  
Alexandre Brosse ◽  
Hédi Hamdi
Keyword(s):  
Residual Stresses ◽  
Surface Integrity ◽  
Metal Cutting ◽  
White Layer ◽  
Ground Surface ◽  
Video Camera ◽  
Fe Model ◽  
Measured Temperature ◽  
Digital Video Camera ◽  
Cutting Processes

Grinding is one of the important metal cutting processes used extensively in the finishing operation to get components of desired shape, size and accuracy. A perfect control of this process is thus necessary to ensure correct final part and limit damage. Lifetime of machined part depends on the surface integrity especially in terms of microstructure changes and residual stresses. The best way to control those factors is to study the way they appear. Thus, it is important to set up experimentation to get the maximum informations during the grinding process, with in situ measurements and after, on the final surface. On one side, forces and power were measured, on the other side temperature measurements were conducted using an infrared digital video camera. In fact the grinding temperature and the temperature gradients are the major factors which influence surface integrity. Experimentations show white layers in the near ground surface and the measured temperature is higher than the austenitizing temperature. The workpiece subsurface was then characterized by observing and measuring microstructural changes of surface layer. Numerical simulations, using SYSWELD software are performed to formalize what is modeled. Metallurgical transformation is then taken into account in the grinding FE model. The comparison showed that numerical model is capable to accurately predict the white layer thickness and residual stresses values.

Analysis of Reversible Fine Machining Sequence Effect on Surface Integrity

2006 ◽  
Vol 315-316 ◽  
pp. 391-395
Author(s):  
Wen Ge Wu ◽  
Si Qin Pang ◽  
Zhan Qiang Liu
Keyword(s):  
Surface Roughness ◽  
Residual Stresses ◽  
Surface Integrity ◽  
Machining Process ◽  
Processing Route ◽  
Machining Accuracy ◽  
Machining Efficiency ◽  
Micro Hardness ◽  
Rough Machining ◽  
Machined Surface

Reversible cutting method is a new research thesis proposed to shorten processing route, decrease tool number and handling time, increase machining efficiency. The aim of the presented work was to analysis the effects of reversible fine machining sequence on surface integrity in machined layer. Nonlinear hardening during reverse loading and the change of the Bauschinger effect factor with plastic strain were properly taken into account. In experiments, the residual stresses have been measured using the X-ray diffraction technique (at the surface of the workpiece and in depth). Moreover, micro-hardness and surface roughness of machined surface are presented. Experimental data for the range of cutting parameters tested showed that the reversible fine machining produce the tensile residual stresses at the surface, which are critical in the performance of the machined components. The experimental results of micro-hardness of reversible fine machining technique are smaller than that of general fine machining show that decreased plastic deformation of the surface layer and work-hardening. Surface roughness of machined surface with reversible finishing is discussed. Research results indicted that it can be adopted such planning which rough machining during advance stroke and fine machining or semi-finishing during return stroke in machining process. In this way, it has such advantages that increase machining efficiency and machining accuracy, decrease bending deformation.

Simulation of Residual Stress in Ultrasonic Vibration Assisted Micro-Milling

2011 ◽  
Vol 188 ◽  
pp. 381-384 ◽  
Author(s):  
Hai Jun Hu ◽  
Ya Zhou Sun ◽  
Z.S. Lu
Keyword(s):  
Residual Stresses ◽  
Ultrasonic Vibration ◽  
Process Parameters ◽  
Shear Failure ◽  
Sliding Friction ◽  
Micro Milling ◽  
Work Piece ◽  
Fe Model ◽  
Optimal Process ◽  
Surface Residual Stresses

The machining-induced residual stresses are strongly dependent on the work-piece material and the chosen process parameters. A 2D finite element (FE) model of ultrasonic vibration assisted micro-milling (UVAMM) is established using ABAQUS. Johnson-Cook’s work-piece material and shear failure principle are used, while friction between tool and work-piece uses modified Coulomb’s law whose sliding friction area is combined with sticking friction. By means of FE analysis, the influence rules of spindle speed, vibration frequency and work-piece material on the surface residual stresses are obtained, which provides a basis for choosing optimal process parameters and improving the longevity and reliability of micro-component.

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