Download or read book Three dimensional Transient Residual Stress Finite Element Analysis for Single and Double Pass Laser Aided Direct Metal material Deposition Process written by Suhash Ghosh and published by . This book was released on 2003 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This thesis is an attempt towards a methodology of finite element analysis (FEA) for the prediction of quenching related macroscopic as well as microscopic residual stresses in laser aided DMD process."--Abstract, p. iii.

Download or read book Numerical Analysis of Thermal Stress and Deformation in Multi layer Laser Metal Deposition Process written by Heng Liu and published by . This book was released on 2014 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Direct metal deposition (DMD) has gained increasing attention in the area of rapid manufacturing and repair. It has demonstrated the ability to produce fully dense metal parts with complex internal structures that could not be achieved by traditional manufacturing methods. However, this process involves extremely high thermal gradients and heating and cooling rates, resulting in residual stresses and distortion, which may greatly affect the product integrity. The purpose of this thesis is to study the features of thermal stress and deformation involved in the DMD process. Utilizing commercial finite element analysis (FEA) software ABAQUS, a 3-D, sequentially coupled, thermo-mechanical model was firstly developed to predict both the thermal and mechanical behavior of the DMD process of Stainless Steel 304. The simulation results show that the temperature gradient along height and length direction can reach 483 K/mm and 1416 K/mm, respectively. The cooling rate of one particular point can be as high as 3000 K/s. After the work piece is cooled down, large tensile stresses are found within the deposited materials and unrecoverable deformation exists. A set of experiments then were conducted to validate the mechanical effects using a laser displacement sensor. Comparisons between the simulated and experimental results show good agreement. The FEA code for this model can be used to predict the mechanical behavior of products fabricated by the DMD process and to help with the optimization of design and manufacturing parameters."--Abstract, page iii.

Download or read book Prediction of Residual Stresses in Laser Glazing and Laser Powder Deposition Processes Using FEM written by Prashanth Kumar Tirukovelluri and published by . This book was released on 2007 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of the research is to develop a three-dimensional finite element model for predicting residual stresses that evolve during the Laser Powder Deposition of thin-walled builds using commercially available finite element software, ABAQUS/Standard [5]. The research work was started by developing a finite element model of Laser Glazing process, which is relatively simple when compared to Laser Powder Deposition in modeling perspective as there is no dynamic addition of material. The experience gained from modeling of Laser Glazing was applied to develop a finite element model of Laser Powder Deposition for prediction of residual stresses. The numerical model of Laser Glazing is based on sequentially coupled thermo-mechanical theory and Laser Powder Deposition process on fully coupled thermo-mechanical theory. To simplify the models, symmetry of geometry and boundary conditions were taken into account. In both the models temperature dependent material properties were included. Also, latent heat corresponding to melting was taken into account. The material was defined as elastic-perfectly plastic. The results predicted by the thermal model of Laser Glazing are comparable with analytical solution and are also validated with the results obtained from carefully designed experiments. In the case of finite element model of Laser Powder Deposition, it can be concluded that the results obtained are reasonable based on previous experimental studies by others.

Download or read book Simulation of Metal Forming Processes by the Finite Element Method SIMOP I written by Kurt Lange and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book 3D FEA Simulations in Machining written by Panagiotis Kyratsis and published by Springer Nature. This book was released on 2023-03-14 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers machining simulations using advanced nonlinear finite element analysis (FEA) methodologies coupled with CAD-based techniques. The content increases awareness about the possibilities to reduce the actual experimental work via experimentally validated simulations using nonlinear finite element analysis.

Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1993 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Process Design of Three dimensional Open die Forging and the Deformation Analysis of Metal Matrix Composites written by Chinghua Hung and published by . This book was released on 1990 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Computer aided Preform Design in Metal Forming by the Finite Element Method written by Naksoo Kim and published by . This book was released on 1989 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Hybrid Additive Manufacturing written by Guha Manogharan and published by Academic Press. This book was released on 2020-07 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hybrid Additive Manufacturing: Techniques, Applications and Benefits explains the fundamentals of hybrid AM, definitions, classifications, and principles, as well as key techniques of hybrid AM, its applications, design guidelines, and benefits, with emphasis on key aspects of the system integration process. The core of this subject is in describing how to overcome inherent processing limitations of layer-by-layer AM through the integration of secondary post-processing such as machining or heat treatment. As a result hybrid AM plays a critical role in accelerating the adoption of AM in established design and manufacturing activities. The applications of hybrid AM in both metals and polymers are discussed in this book, as are geometrical dimensioning and tolerancing, material property enhancement, non-traditional surface finishing, in-situ sequential hybrid processing, and integrated process planning. This book will serve not only as an introduction to hybrid AM but also as a handbook for researchers and engineers in mechanical, manufacturing, industrial, electronics, and materials science, thanks to its interdisciplinary approach and detailed case studies. Explains how hybrid manufacturing processes can be used to achieve enhanced material properties and functionality Describes the significance of hybrid additive manufacturing to different parts of the process chain Uses case studies to show how innovative companies are using this technology, how they have overcome challenges they encountered, and the benefits they have experienced

Download or read book New Challenges in Residual Stress Measurements and Evaluation written by Caterina Casavola and published by BoD – Books on Demand. This book was released on 2020-07-22 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: Residual stresses (RS) are stresses present inside materials even in the absence of any applied load. They are of capital importance because they can impact greatly on the mechanical strength of the material, on its dimensional correspondence to design specifications as well as on the fatigue life of the part. RS measurement and evaluation is currently an important research topic where a lot of challenges still need to be addressed. This book aims to provide the reader with an overview of the principal novelties in this field including current limitations and potential future developments. Both radically new experimental approaches as well as recent evolutions of consolidated ones will be presented, along with the latest novelties in the area of numerical residual stress evaluation.

Download or read book Study of Stress Developments in Axi symmetric Products Fabricated by Forging and Machining written by Jiann-Haw Liou and published by . This book was released on 1996 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: Residual stress distribution on manufactured surfaces can decide component performance, longevity, and reliability by affecting material stability, resistance to deformation, accuracy, and fatigue life of products. In order to extend the operating life of products and satisfy the quality of operation during customer usage, it is necessary to monitor residual stresses in parts during the manufacturing process. Design for manufacturing (DFM) is a way to provide design engineers with complete information on the characteristics of product quality. Designers can then decide remedial manufacturing procedures, if necessary, in the design stage without requiring actual manufacturing operation. As a way to develop a computing tool for the DFM and stress information in products, a three-dimensional finite element model to simulate a continuous manufacturing process from forging to machining was developed using a nonlinear finite element program. In the simulation, MILS 11595 was used as workpiece material and stress developments in each stage of operation were calculated. The final residual stress distributions due to forging and machining process were also calculated. The selected calculation results were compared with experimental data and published works to verify the effectiveness of the developed model. Parametric studies of the manufacturing processes of forging and machining were performed to obtain optimum residual stresses in the products. Two-dimensional finite element method and Taguchi method were used to identify the controlling process parameters which had direct effects on the residual stress formation. In the optimization, experimental planning was performed by using the matrix experiment and the signal-to-noise ratio was used in the ANOVA analysis. Frictional coefficients, length of die land, and inlet angle were selected as process parameters in the forging operation. Cutting Speed, feed rate, and depth of cut were selected as controlling process parameters in the machining operation. The deviation of workpiece material was selected as the noise factor. The ANOVA analysis showed that the inlet angle had the most significant effect on optimum forged residual stresses. The feed rate and depth of cut had the most significant effect on machined residual stresses.

Download or read book International Conference on Residual Stresses written by G. Beck and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 1043 pages. Available in PDF, EPUB and Kindle. Book excerpt: Residual stresses are always introduced in materials when they are produced, or when they undergo non-uniform plastic deformation during use. The circumstances that can cause residual stresses are therefore numerous. Residual stresses exist in all materials and, depending on their distribution, can playa beneficial role (for example, compressive surface stress) or have a catastrophic effect, especially on fatigue behaviour and corrosion properties. The subject of residual stresses took form around 1970 with the development of methods to measure macroscopic deformations during the machining of materials or on an atomic scale by X-ray diffraction. These techniques have made considerable progress in the last 20 years. The meetings organized in several countries (Germany, France, Japan, etc. ) have largely contributed to this progress, aided by the numerous exchanges of information and knowledge to which they have given rise. Studies of the formation of residual stresses began more slowly, but have progressed with the emergence of increasingly realistic models of materials behaviour and with access to ever more powerful codes for numerical calculations. Two successive meetings for discussing this topic have been held in Europe. The first, held in 1982 in Nancy (France), consisted of 30 participants from 5 countries. The second was held in Linkoping (Sweden) in 1984, with 80 participants of 16 nationalities. It was decided to hold a first International Conference, ICRS, to address all aspects of the problem. Held in 1986 in Garmisch-Partenkirschen (FRG), it was an assembly of neady 300 participants from 21 countries.

Download or read book Residual Stresses 2018 written by Marc Seefeldt and published by Materials Research Forum LLC. This book was released on 2018-10-10 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: The European Conference on Residual Stresses (ECRS) series is the leading European forum for scientific exchange on internal and residual stresses in materials. It addresses both academic and industrial experts and covers a broad gamut of stress-related topics from instrumentation via experimental and modelling methodology up to stress problems in specific processes such as welding or shot-peening, and their impact on materials properties. Chapters: Diffraction Methods; Mechanical Relaxation Methods; Acoustic and Electromagnetic Methods; Composites, Nano and Microstructures; Films, Coatings and Oxides; Cold Working and Machining; Heat Treatments and Phase Transformations; Welding, Fatigue and Fracture: Stresses in Additive Manufacturing.

Download or read book Adaptive Layer Process Control of Laser Aided Direct Metal material Deposition Process written by Yusheng Hua and published by . This book was released on 2004 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt: "It has been acknowledged that close-loop feedback control of laser aided direct metal/material deposition (DMD) process is critical to deliver this revolutionary rapid manufacturing technology into industry. The primary concern in applying the control technique is how precisely the deposition dimension can be achieved; however, the challenge to implement it comes from how to control the deposition height effectively. This research work investigates height control methods to achieve the dimensional precision, for typical cases such as uniform depsoition, adaptive, and non-uniform deposition, based on optical height sensing technology--Abstract, leaf iii.

Download or read book Heat Effects of Welding written by Dieter Radaj and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 367 pages. Available in PDF, EPUB and Kindle. Book excerpt: Almost all welding technology depends upon the use of concentrated energy sources to fuse or soften the material locally at the joint, before such energy can be diffused or dispersed elsewhere. Although comprehensive treatments of transient heat flow as a controlling influence have been developed progressively and published over the past forty years, the task of uniting the results compactly within a textbook has become increasingly formidable. With the comparative scarcity of such works, welding engineers have been denied the full use of powerful design analysis tools. During the past decade Dr Radaj has prepared to fulfil this need, working from a rich experience as pioneer researcher and teacher, co-operator with Professor Argyris at Stuttgart University in developing the finite element method for stress analysis of aircraft and power plant structures, and more recently as expert consultant on these and automotive structures at Daimler Benz. His book appeared in 1988 in the German language, and this updated English language edition will significantly increase the availability of the work.

Download or read book Thermo Mechanical Modeling of Additive Manufacturing written by Michael Gouge and published by Butterworth-Heinemann. This book was released on 2017-08-03 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermo-mechanical Modeling of Additive Manufacturing provides the background, methodology and description of modeling techniques to enable the reader to perform their own accurate and reliable simulations of any additive process. Part I provides an in depth introduction to the fundamentals of additive manufacturing modeling, a description of adaptive mesh strategies, a thorough description of thermal losses and a discussion of residual stress and distortion. Part II applies the engineering fundamentals to direct energy deposition processes including laser cladding, LENS builds, large electron beam parts and an exploration of residual stress and deformation mitigation strategies. Part III concerns the thermo-mechanical modeling of powder bed processes with a description of the heat input model, classical thermo-mechanical modeling, and part scale modeling. The book serves as an essential reference for engineers and technicians in both industry and academia, performing both research and full-scale production. Additive manufacturing processes are revolutionizing production throughout industry. These technologies enable the cost-effective manufacture of small lot parts, rapid repair of damaged components and construction of previously impossible-to-produce geometries. However, the large thermal gradients inherent in these processes incur large residual stresses and mechanical distortion, which can push the finished component out of engineering tolerance. Costly trial-and-error methods are commonly used for failure mitigation. Finite element modeling provides a compelling alternative, allowing for the prediction of residual stresses and distortion, and thus a tool to investigate methods of failure mitigation prior to building. - Provides understanding of important components in the finite element modeling of additive manufacturing processes necessary to obtain accurate results - Offers a deeper understanding of how the thermal gradients inherent in additive manufacturing induce distortion and residual stresses, and how to mitigate these undesirable phenomena - Includes a set of strategies for the modeler to improve computational efficiency when simulating various additive manufacturing processes - Serves as an essential reference for engineers and technicians in both industry and academia

Download or read book Advancement in Thermo material Modeling of Direct Energy Deposition Processes written by Michael Gouge and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this work is to advance the abilities of finite element models of direct energy deposition (DED) processes. DED uses a laser or electron beam to melt either metallic powder or wire, which is controlled numerically to deposit the material onto a substrate or existant component. Computational models of DED processes are used for two primary reasons: process parametization and prediction of material properties. For the first reason, thermo-mechanical models are completed to determine the distortion and residual stresses that develop due to the high thermal gradients inherent during deposition. With accurate models, investigations can be made to mitigate these negative phenomena by alteration of process parameters including laser power, laser path, and environmental conditions. For the 2nd modeling motivation, thermal models are completed from which the thermal gradients, cooling rates, or solidification rates may be computed, which are the phenomenon which drive microstructural development, which in turn determines the final material properties of the deposited material.While DED technology is mature, having long been used to rapidly clad, repair, or build new components, the modeling of these processes is only now able to achieve the accuracy and speed necessary for industrial implementation. In this work finite element (FE) models are developed and validated for DED processes. In situ measurements of temperature are taken during the single layer laser cladding of Inconel® 625625. These are used to develop and validate the application of thermal boundary conditions aiming to improve model accuracy. First, the application of convection boundary conditions are explored. During DED deposition, the gases used to propel the powder and prevent material contamination in the melt pool cause a significant convective cooling. Comparisons are made between various methods of applying convection including using natural convection only, forced convection measured from the lumped capacitance method, convection from an impinging jet heat transfer paper, convection measured by hot film anemometry, and ignoring convection. The importance of applying convection to the evolving free surface was also investigated. It was shown that using the hot film anemometry values applied to an evolving free surface yielded the most accurate model, with 3-13% error. Secondly, conduction losses due to fixturing during laser cladding processes were investigated. Two Inconel® 625625 laser cladding experiments were completed, each using identical processes parameters, one which was held in a cantilevered fixture, one bolted directly to the work bench. These represent the minimum and maximum contact area during deposition. In situ measurements of temperature were taken, which were used for the calibration and validation of the subsequent thermal simulations. Though two bodies may be in contact, there is a loss of thermal conduction at their junction due to the microscopic irregularities of the surfaces. The drop in thermal heat transfer is called contact resistance and the effective conductivity through the point of contact is called gap conductance. A method for estimating the maximum gap conductance and application to FE models was developed. Calibration of gap conductance was completed for each experimental case. For the cantlivered clad, it was estimated that that merely 2% of the total heat loss occurred through the fixture. Application of the gap conductance model improved the accuracy of the model near the point of contact, but did not greatly affect the remainder of the substrate or clad material. For the work bench bolted clad, it was estimate that between 70-85% of the input heat left via conduction. It was shown that the accuracy of the thermal model for this case was vastly improved by using the gap conductance model, but that the effectiveness of the modeling was limited somewhat by the thermo-mechanical interaction. With the improved accuracy of the thermal models gained by the preceding advancements in boundary condition handling, the focus was shifted towards capturing the material solidification and ensuing microstructure with the FE model. To this end, single track depositions were performed using 4 sets of laser power and scan speed, for both Inconel® 625625 and Ti-6Al -4V. Type K thermocouples were used for far-field validation of the thermal model while high temperature Type C thermocouples were threaded through the underside of the substrate, to lay flush with the surface. This allowed for the in situ measurement of melt pool temperatures during deposition. Post process, the plates were sectioned and the melt depth was measured. Two modeling techniques were used to improve the accuracy for attaining both of these measured phenomenon: altering the melt temperature specific heat to account for changes in liquid density and altering the melt temperature thermal conductivity to approximate convection within the melt pool. This method reduced the simulated melt depth error to under 10% for 5 of the cases and the simulated melt temperature error under 25% for all 8 cases. It being concluded the model can accurately predict melt pool behavior, a model for predicting the material properties of laser clad Inconel® 625 was developed. Empirical correlations have been produced from Inconel® 625 hardness, yield strength, and microstructure measurements from published works from a variety of AM processes. Using the preceding single track study it was shown that using similar processing parameters the model could approximate the solidification time. It is the solidification time which controls the microstructure of Inconel® 625. The thermo-property model was calibrated against microstructure and hardness measurements from the laser clad. Experimental measurements of microstructure, hardness, and yield strength from 3 Inconel® 625 wall builds were used to validate the semiempirical model.This work yields a pathway from the process parameters to the material properties of laser clad Inconel® 625 which can be used to estimate or design the mechanical properties of DED Inconel® 625 components.