Optimised implementation of physics-based strain-rate dependent material models for the improved simulation of the laser shock peening process PDF Download

Author: Dylan Amfield
Publisher:
ISBN:
Category : Laser peening
Languages : en
Pages : 93

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Book Description

Author: K. Ding
Publisher: CRC Press
ISBN: 9780849334443
Category : Technology & Engineering
Languages : en
Pages : 182

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Book Description
Laser shock peening (LSP) is a process for inducing compressive residual stresses using shock waves generated by laser pulses. It is a relatively new surface treatment for metallic materials that can greatly improve their resistance to crack initiation and propagation brought on by cyclic loading and fatigue. This book, the first of its kind, consolidates the scattered knowledge about LSP into one comprehensive volume. It describes the mechanisms of LSP and its substantial role in improving fatigue performance in terms of modification of microstructure, surface morphology, hardness, and strength. In particular, it describes numerical simulation techniques and procedures that can be adopted by engineers and research scientists to design, evaluate, and optimize LSP processes in practical applications.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 80

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Book Description
Laser Shock Peening (LSP) is a relatively new material processing technology to enhance the operating service lives of engineering components. It has been applied to metal parts such as aircraft engine turbine blades, compressor blades and medical implants like human hip joints. In this process shock waves are generated in the material using a high powered laser beam which develops residual stresses in the material. It has been proved experimentally that the life cycle of laser shock peened components are higher than conventionally shot peened components. Although LSP process has been found to be effective, improper control of the process will lead to spallation in the material under certain conditions. The spallation within the material in the form of crack significantly reduces the operating life of the component. Currently there is no systematic modeling approach to predict the material response under LSP. As such, the objective of this thesis is to develop a comprehensive model for the predicting the material response as a result of the LSP process. More specifically a pressure model is first established to obtain the pressure loading based on laser pulse intensity. Using the pressure load as input the spallation response is simulated by developing a strain rate and temperature dependent material model. The material model is implemented along with a nucleation and growth based damage model. The material and dynamic fracture model is solved using a semi-implicit forward tangent modulus algorithm. A user defined subroutine (UDM) is written and combined with the analysis tool LS-DYNA. The new model is compared with reported experimental results and a parametric study is done to understand the influence of various processing parameters. The residual stress obtained from simulation is in good agreement with experimental results. The spallation results have not been verified due to lack of experimental data.

Author: Shikun Zou
Publisher: Springer Nature
ISBN: 9819911176
Category : Science
Languages : en
Pages : 398

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Book Description
This book highlights the fundamentals and latest progresses in the research and applications of laser shock peening (LSP). As a novel technology for surface treatment, LSP greatly improves the resistance of metallic materials to fatigue and corrosion. The book presents the mechanisms, techniques, and applications of LSP in a systematic way. It discusses a series of new progresses in fatigue performance improvement of metal parts with LSP. It also introduces lasers, equipment, and techniques of newly developed industry LSP, with a detailed description of the novel LSP blisk. The book demonstrates in details numerical analysis and simulation techniques and illustrates process stability control, quality control, and analysis determination techniques. It is a valuable reference for scientists, engineers, and students in the fields of laser science, materials science, astronautics, and aeronautics who seek to understand, develop, and optimize LSP processes.

Author: Liucheng Zhou
Publisher: Springer Nature
ISBN: 9811617473
Category : Technology & Engineering
Languages : en
Pages : 241

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Book Description
This book introduces the fundamentals and principles of laser shock peening (LSP) for aeronautical materials. It focuses on the innovation in both theory and method related to LSP-induced gradient structures in titanium alloys and Ni-based alloys which have been commonly used in aircraft industries. The main contents of the book include: the characteristics of laser shock wave, the formation mechanism of gradient structures and the strengthening-toughing mechanism by gradient structures. The research has accumulated a large amount of experimental data, which has proven the significant effectiveness of LSP on the improvement of the fatigue performance of metal parts, and related findings have been successfully applied in aerospace field. This book could be used by the researchers who work in the field of LSP, mechanical strength, machine manufacturing and surface engineering, as well as who major in laser shock wave and materials science.

Author: José Luis Ocaña
Publisher:
ISBN: 9783039367986
Category :
Languages : en
Pages : 208

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Book Description
Laser shock processing (LSP) is a continuously developing effective technology used to improve surface and mechanical properties for metallic alloys. LSP is in direct competition with other established technologies, such as shot peening, both in preventive manufacturing treatments and maintenance/repair operations. The level of LSP maturity has increased in recent years and several thematic international conferences have been organized (i.e., the 7th ICLPRP held in Singapore, June 17-22, 2018) to discuss different developments of a number of key aspects. These aspects include: fundamental laser interaction phenomena; material behavior at high deformation rates/under intense shock waves; laser sources and experimental process implementation; induced microstructural/surface/stress effects; mechanical and surface properties with experimental characterization and testing; numerical process simulation; development and validation of applications; comparison of LSP to competing technologies; and novel related processes. All of these aspects have been recursively treated by well-renowned specialists, providing a firm basis for the further development of the technology in its path to industrial penetration. However, the application of LSP (and related technologies) on different types of materials with different applications (such as the always demanding aeronautical/aerospatial field or the energy generation, automotive, and biomedical fields) still requires extensive effort to elucidate and master different critical aspects. Thus, LSP deserves a great research effort as a necessary step prior to its industrial readiness level. The present Special Issue of Metals in the field of "Laser Shock Processing and Related Phenomena" aims, from its initial launching date, to collect (especially for the use of LSP application developers in different target sectors) a number of high-quality and relevant papers representing state-of-the-art technology that is useful to newcomers in realizing its wide and relevant prospects as a key manufacturing technology. Consequently, in an additional and complementary way, papers were presented at the thematic ICLPRP conferences, and a call was made to authors willing to prepare high-quality and relevant papers to the journal, with the confidence that their work would become part of a fundamental reference collection regarding the present state-of-the-art LSP technology. The Special Issue includes two reviews and nine research papers. Each contribution adds to the reference knowledge of LSP technology and covers the practical totality of open issues, which will lead to present-day research at worldwide universities, research centers, and industrial companies.

Author: Yongkang Zhang
Publisher: Springer Science & Business Media
ISBN: 3642356745
Category : Technology & Engineering
Languages : en
Pages : 200

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Book Description
Laser shock processing (LSP) is a new and promising surface treatment technique for improving the fatigue durability, corrosion, wear resistance and other mechanical properties of metals and alloys. During LSP, the generated shock wave can introduce a deep compressive residual stress into the material, due to its high-pressure (GPa-TPa), ultra-fast (several tens nanoseconds), ultra-high strain-rate and high-energy. The overall properties and behavior of metal materials subjected to LSP were significantly improved because a refined surface layer was successfully obtained. Nevertheless, up to now, a clear scenery between micro-structure and macro-property of the refined surface layer, especially formation of sub-micrometer grains from coarse grains during severe plastic deformation, is still pending. Therefore, the basic studies of the underlying mechanism for grain refinement by ultra-high strain-rate presented in this book becomes more and more crucial.

Author: Chinmay J. Tophkhane
Publisher:
ISBN:
Category :
Languages : en
Pages : 56

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Book Description
This thesis focuses on a physically based strain rate dependent plasticity model known as the Mechanical Threshold Stress (MTS) model proposed by Follansbee and Kocks. The objective is to develop an algorithm based on the tangent modulus method to resolve the constitutive equation represented by the MTS model and use it to analyze the material response under laser shock peening for the Ni alloy INCONEL 718 (IN718). A user defined subroutine has been developed and integrated with commercial software LS-DYNA. A parametric study is carried out to study the influence of various model parameters on the predicted residual stresses. The developed model is then applied in the study of residual stresses imparted on INCONEL 718 induced by laser shock peening (LSP) process. Finite element analysis is performed for the case of plate made of INCONEL 718 and the residual stress predictions are compared with experimental results. The model predictions are found to be in good agreement with the experimental results. To the best of author's knowledge, this is the first time that an MTS model has been developed for IN 718 with an integrated approach.

Author: Hemanth Amarchinta
Publisher:
ISBN:
Category : Laser peening
Languages : en
Pages : 184

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Book Description
Advanced mechanical surface enhancement techniques have been used successfully to increase the fatigue life of metallic components. These techniques impart deep compressive residual stresses into the component to counter potentially damage-inducing tensile stresses generated under service loading. Laser Peening (LP) is an advanced mechanical surface enhancement technique used predominantly in the aircraft industry. To reduce costs and make the technique available on a large-scale basis for industrial applications, simulation of the LP process is required. Accurate simulation of the LP process is a challenging task, because the process has many parameters such as laser spot size, pressure profile, and material model that must be precisely determined. In the LP process material is subjected up to strain rates of 106 per second, which is very high compared to conventional strain rates. The importance of an accurate material model increases because the material behaves significantly different at such high strain rates. One of the objectives of this research is to make advancements in the simulation of residual stresses induced by laser peening. Validation of various material models under investigation that could be used in simulation and design is performed. Inverse optimization-based methodology is developed for simulation of residual stresses for materials such as Inconel718. The procedure involves optimizing the model constants for one load case and using the same constants for other load cases. The second aspect of this research is to develop a framework for uncertainty quantification of the residual stress field induced by the LP process by propagation of regression uncertainty. Development methodology includes identification of regression uncertainty as a source of input uncertainty and using the bootstrap method to verify the multivariate normality assumption of the model constant estimates. The propagation of the input uncertainty is performed using Taylor series expansion and sensitivity analysis. A confidence band for the entire residual stress field is obtained and validated using the Monte Carlo analysis.

Author: Xudong Ren
Publisher: Springer
ISBN: 9783662515020
Category : Technology & Engineering
Languages : en
Pages : 0

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Book Description
The aim of this book is to present foundational research on the nano-crystallization, high-temperature modification, micro-structure evolution and plastic deformation induced by laser shock processing. In this regard, the focus is on heat-resistant steel, aluminum alloy, Ti alloys and Ni-based alloys, offering valuable scientific insights into the industrial applications of laser shock processing (LSP) technology. The book addresses various topics, i.e., the formation mechanism and productivity improvement of nano-crystalline diamond by laser processing, the surface integrity and fatigue lives of heat-resistant steels, Ti alloys and Ni-based alloys after LSP with different processing parameters, tensile properties and fractural morphology after LSP at different temperatures, strain-rates and grain refinement mechanisms based on the micro-structure evolution. Moreover, the effect of heating temperature and exposure time on stress thermal relaxation and the influence of compressive stress on the stress intensity factor of hole-edge cracks by high strain rate laser shock processing are also analyzed. A new type of statistical data model to describe the fatigue cracking growth with limited data is proposed based on the consideration of the effects of fracture growth on the reliability and confidence level. This book is intended for researchers, engineers and postgraduates in the fields of nanotechnology and micro-engineering who are interested in the partial or overall strengthening of materials, especially those with a focus on surface integrity and fatigue life.