bluuebunny/crossref_metadata_2025 huggingface dataset:
Contact Fatigue of Hardened Steels
Authors: Hyde R. Scott
Published: December 2018

The mechanism of contact fatigue can be understood in terms of several sources of stress concentration, or stress raisers, within the macroscopic Hertzian stress field. This article focuses primarily on rolling contact fatigue of hardened bearing steels. It discusses Hertzian shear stresses at and below the contact surfaces and briefly summarizes bearings and gear characteristics. The article provides an overview of the key types of gear and bearing steels. It analyzes two types of macropitting that result from the subsurface growth of fatigue cracks, namely, subsurface-origin macropitting and surface-origin macropitting. The article describes the factors influencing contact fatigue life of hardened steel bearings and gears, including hardness, inclusions, carbides, and residual stresses.
Overview of the Design Process
Authors: Dixon John R.
Published: December 2018

This article presents an overview of an engineering design process. Though the process is extremely complex, distinct stages of design activities are identified and described. The article illustrates guided iteration methodology that helps in problem solving in design. It describes the engineering conceptual design and configuration design of special-purpose parts. It discusses the parametric design methods of the parts and best practices that are used by successful firms to achieve the goals of quality, cost, time-to-market, and marketing flexibility.
Cross-Functional Design Teams
Authors: Smith Preston G.
Published: December 2018

The most effective design teams generally involve a clearly delineated group of individuals who work full time on the specified project from its beginning until market introduction. This article focuses on issues arising in using teams in a product design process. It provides special coverage on alternative roles for specialists, such as materials engineers or scientists, whose expertise is essential to the success of the project. The article discusses the types of teams exhibiting certain characteristics in the sales, accounting, and research departments and from the factory floor to the executive suite. The special characteristics of cross-functional development teams are discussed. The article reviews the staffing of a development team, including team leader, team members, and suppliers on the team. It describes the considerations for organizing a development team, and the role of development team specialists on balancing team needs.
Designing to Codes and Standards
Authors: Hunter Thomas A.
Published: December 2018

This article discusses the need, purposes, and objectives of codes and standards. It describes several types of codes, such as safety and trade codes, and the different types of standards, namely, industry consensus standards, product definition standards, and commercial standards. The article provides information on organizations that prepare codes and standards. It tabulates sponsoring organizations for the standards published by the American National Standards Institute and concludes with a discussion on a designer's responsibilities.
Safety in Design
Authors: Smith Charles O.
Published: December 2018

Any threat to personal safety should be regarded as a hazard and treated as such. This article discusses threats from several sources, such as kinematic/mechanical hazards, electrical hazards, energy hazards, human factors/ergonomic hazards, and environmental hazards. It describes hazard analysis in terms of failure modes and effects analysis, failure modes and criticality analysis, fault tree analysis, fault hazard analysis, and operating hazards analysis. The article examines fail-safe designs, such as fail-passive designs, fail-active designs, and fail-operational designs. It also provides information on various types of warnings, such as visual warning, auditory warnings, olfactory warnings, tactile warnings, and tastable warnings.
Finite Element Analysis
Authors: Dewhirst Donald L.
Published: December 2018

Finite element analysis is a computer-based numerical method for solving engineering problems in bodies of user-defined geometry. This article introduces the important issues of finite elements (especially accuracy and efficiency) in a nonacademic manner. It describes the Rayleigh-Ritz procedure for solving structural problems based on the principle of virtual work. The article discusses continuum elements, such as hexahedra, pentahedra, tetrahedra, quadrilaterals, and triangles, commonly used in three- or two-dimensional domains. It considers structural elements such as beam element, plate element, shell element, and elbow element. The article presents three examples to illustrate the types of problems that can be addressed and the decisions that must be made when using finite element analysis.
Design Optimization
Authors: Smith Douglas E.
Published: December 2018

This article discusses tools that are used for the systematic optimization of engineering designs. It focuses on the practical application of optimization technology in a computer-aided engineering environment. The article presents numerical optimization algorithms and provides some background on how these algorithms make decisions when searching for the optimal design. It also provides information on structural optimization, topology optimization, materials processing optimization, multidisciplinary optimization, and global optimization.
Rapid Prototyping
Authors: Thomas Charles L.
Published: December 2018

Rapid prototyping (RP) is a field in manufacturing involving techniques/devices that produce prototype parts directly from computer-aided design models in a fraction of time. This article discusses the principles of RP and three major commercial processes, based on their layer creation method. These include selective cure layered processes, extrusion/droplet deposition processes, and sheet form fabricators. The article provides information on the three classes of RP, namely, voxel sequential volume addition, periphery cutting, and area sequential volume addition. It presents equations that represent build times for each of the three classes.
Effects of Composition, Processing, and Structure on Properties of Composites
Authors: Laramee R.
Published: December 2018

This article describes the interaction of composition, manufacturing process, and composite properties of composites. The manufacturing process includes resin-matrix, metal-matrix, and carbon/carbon matrix processing. The article discusses various mechanical properties of composites. It explores how variations in the composition, manufacturing, shop process instructions, and loading/environmental conditions can affect the use of a composite product in a performance/service life operation.
Design for Fatigue Resistance
Authors: Krempl Erhard
Published: December 2018

The design of components against fatigue failure may involve several considerations of irregular loading, variable temperature, and environment. This article focuses on design considerations against fatigue related to material performance under mechanical loading at constant temperature. It reviews the traditional methods of fatigue design on smooth and notched components. The article discusses high-cycle fatigue in terms of fatigue strength and tensile strength, mean stress effects, stress concentration, and multiaxial fatigue. It describes low-cycle fatigue in terms of deformation behavior and concludes with a discussion on lifetime analysis based on a strain approach.
Design for Corrosion Resistance
Authors: Ford F. Peter , Andresen Peter L. , Elliott Peter
Published: December 2018

This article discusses the principles of corrosion and the basis of the various prevention measures that can be taken for different corrosion modes. It describes aqueous corrosion phenomena in terms of the electrochemical reactions that occur at the metal-environment interface. The article explains the specific forms of corrosion, including general corrosion, localized attack, and environmentally assisted cracking. It provides a discussion on the engineering aspects of design that can, without due care and attention, precipitate unexpected premature failure. The article reviews ways to improve corrosion awareness and prevent corrosion/degradation. It describes a life prediction method with an example of environmental degradation in light-water nuclear reactors. The article concludes with a discussion on the validation of life-prediction algorithms and their applications.
Design for Wear Resistance
Authors: Bayer Raymond G.
Published: December 2018

Wear is the damage to a solid surface as a result of relative motion between it and another surface or substance. This article discusses the four general ways by which a material can wear, namely, adhesive wear, abrasive wear, fatigue or fatigue-like wear, and corrosive wear. It tabulates the operational classification of wear situations and describes the relationship between wear or wear rate and design parameters. The article reviews the effect of lubrication on wear behavior and the types of lubricants. It illustrates some fundamental criteria that can be applied in the selection of a material for wear applications. The article explains four elements of wear design, such as system analysis, modeling, data gathering, and verification. It concludes with a discussion on the design approach for low-wear computer peripherals.
Design with Plastics
Authors: Trantina G.G.
Published: December 2018

The key to any successful part development is the proper choice of material, process, and design matched to the part performance requirements. Understanding the true effects of time, temperature, and rate of loading on material performance can make the difference between a successful application and catastrophic failure. This article provides examples of reliable material performance indicators and common practices to avoid failure. Simple tools and techniques for predicting part mechanical performance integrated with manufacturing concerns, such as flow length and cycle time, are demonstrated. The article describes the prediction of mechanical part performance for stiffness, strength/impact, creep/stress relaxation, and fatigue.
Manufacturing Cost Estimating
Authors: Hoult David P. , Meador C. Lawrence
Published: December 2018

This article focuses on products defined by dimensions and tolerances and fabricated by some manufacturing process. It describes the general concepts associated with cost estimation. These include domain limitation, database commonality, cost allocation, and elements of cost. The article discusses three methods of cost estimation, namely, parametric methods, empirical methods, and complexity theory, with examples. It concludes with recommendations for cost estimation.
Design for Machining
Authors: Stephenson D.A.
Published: December 2018

Machining or material removal processes are secondary manufacturing operations that are used to achieve precise tolerances or to impart controlled surface finishes to a part. This article summarizes rules for designing parts to improve machined part quality and reduce machining costs in mass and batch production environments. It discusses the factors affecting the total cost of a machining operation, including raw material costs, labor costs, and equipment costs. The article describes three types of machining systems, namely, general-purpose machine tools, production machining systems, and computer numerically controlled (CNC) machining systems. It reviews general design-for-machining rules that are applicable to all parts, regardless of the type of equipment used to produce them. Special considerations for production machining systems and CNC machining systems are discussed. The article describes the structure and typical uses of computer-aided process planning and design-for-manufacturing programs.
Control of Residual Stresses
Authors: Chandra U.
Published: December 2018

This article introduces the fundamental sources of residual stresses common to most manufacturing processes. It explains the effect of material removal on residual stresses and distortions in a part. The article assists the reader in making a choice between trial-and-error and computer-simulation approaches for the control of residual stresses. It provides a summary of the commonly used techniques of measuring residual stresses. The article also describes the finite element method for predicting residual stresses caused by various manufacturing processes. It concludes with a discussion on the operations involved in thermal and mechanical stress-relief methods.
Bio-Based Resins and Natural Fibers
Authors: Wool Richard P. , Khot Shrikant N.
Published: December 2018

This article describes the synthesis, manufacturing, and properties of both the neat soy-based resins and the glass, flax, and hemp composites. A tabulation of the fatty-acid distribution in various plant oils is provided. The article discusses synthetic pathways for triglyceride-based monomers and provides a discussion on acrylated epoxidized soybean oils (AESO), maleinized soyoil monoglyceride (SOMG/MA), and maleinized hydroxylated oil (HO/MA). The polymer properties of the AESO, SOMG/MA, and HO/MA are also discussed. The article explains the ballistic impact resistance of soy resin composites and concludes with a discussion on biodegradable composites.
Cyanate Ester Resins
Authors: Robitaille Susan
Published: December 2018

Cyanate ester resins are a family of high-temperature thermosetting resins that bridge the gap in thermal performance between engineering epoxy and high-temperature polyimides. This article discusses the chemistry, properties and characteristics of the cyanate ester resins. It describes the processing procedures for the cyanate ester resins and provides information on properties for selected applications, such as space applications, radomes, and printed circuit boards.
Thermoplastic Resins
Authors: McKague Lee
Published: December 2018

This article provides information on the thermoplastic resins used as matrix materials for continuous fiber reinforced composites. It focuses on the materials that are suitable for fabrication of structural laminates and used for aerospace applications. The article provides a discussion on the background, categories, characteristics, product forms, properties, cost benefits, and processing techniques of thermoplastic resins. Strategies that have been advanced to deal with impregnation difficulties are also discussed.
Fatigue and Life Prediction
Authors: Schaff Jeffrey R.
Published: December 2018

In the design of composite structures for durability and damage tolerance, the primary concerns are out-of-plane failures, such as delamination, material degradation associated with environment, stability under compression loading, large degree of scatter in fatigue life, and bearing failure of joints. This article presents an introductory discussion on the fatigue damage process, methodologies assessing fatigue behavior, and life prediction models. It describes the damage mechanisms introduced for a quasi-isotropic laminate under tension-compression fatigue loading. Delamination is a critical issue in fatigue and generally results from high interlaminar normal and shear stresses. The article schematically illustrates the structural elements in which high interlaminar stresses are common. It concludes with a discussion on the classification of fatigue models such as mechanistic or phenomenological, for composite materials under cyclic loading.
Damage Tolerance
Authors: Woodward Mike R. , Stover Rich
Published: December 2018

This article addresses the issue of the implementation of composite damage tolerance requirements as it relates to military aircraft. It presents a brief introduction on the durability impact threat, damage tolerance impact threat, and other damage tolerance damage threats. The article summarizes damage tolerance criteria and durability criteria for military aircraft. It discusses the damage tolerance design philosophy for metallic structures and composite structures of the aircraft. The article describes the implementation of a damage tolerance analysis methodology in terms of the mechanics based model, the regression algorithm, and the semi-empirical analysis.
Computer Programs
Authors: Berenberg Barry J.
Published: December 2018

This article begins with a discussion on the criteria for evaluating computer programs for composites structural analysis, including database capabilities, types of engineering calculations supported, interface and operating systems, and technical support. It describes the capabilities of programs, such as CompositePro, ESAComp, and V-Lab that provide a graphical interface, built-in databases, and integrated modules for the different types of analyses. The article reviews the modules of other programs used for composite analysis. The programs include ASCA, CADEC, CoDA, COMPASS, ESDU, LAP, PROMAL, and SACL. The article concludes with information on on-line programs and recourses.
Compression Molding
Authors: Peterson Charles W. , Ehnert G. , Liebold R. , Hörsting K. , Kühfusz R.
Published: December 2018

Compression molding is the single largest primary manufacturing process used for automotive composite applications. This article provides an overview of the compression molding process. It describes the basic design, materials, and processing equipment of three main groups of composite materials, namely, glass-fiber-mat-reinforced thermoplastics, long-fiber-reinforced thermoplastics, and sheet molding compounds. The article also presents information on the application examples and market volume of compression molding.
Introduction to Post-Processing and Assembly
Authors: Campbell Flake C.
Published: December 2018

This article provides a summary of the concepts discussed in the articles under the Section “Post-Processing and Assembly” ASM Handbook, Volume 21: Composites.
Processing and Joining of Thermoplastic Composites
Authors: McCarville Douglas A. , Schaefer Henry A.
Published: December 2018

Advanced thermoplastic composites possess impact resistance, fracture toughness, and elevated temperature endurance properties due to their melt-fusible nature. This article presents the material options available for thermoplastic composites such as pseudothermoplastics, post-impregnated thermoplastics, and true thermoplastics. It describes the processing methods of thermoplastic composites, including weaving, seaming, autoclaving, preconsolidation, roll consolidation, roll forming/pultruding, thermoforming, press forming, hydroforming, and diaphragm forming. The article provides information on different types of joints, namely, fastened, adhesive bonded, dual polymer bonded, co-consolidated, and welded joints. It explains the joining methods of thermoplastic composites, such as press forming, diaphragm forming, autoclaving, ultrasonic welding, resistance welding, and induction welding.
Extrusion of Particle-Reinforced Aluminum Composites
Authors: Harrigan William C.
Published: December 2018

This article discusses the dies, such as shear-face dies, conical-feed dies, and bridge dies, that are used in extrusion of particle-reinforced aluminum composites. It provides an overview of the effects of reinforcements on the properties of aluminum composites.
Introduction to Quality Assurance
Authors: Henson Grover Aaron
Published: December 2018

This article presents the importance of progressing from post-manufacturing inspection/verification to in-process inspection/verification methods. It lists the various quality assurance factors considered for typical composite laminate lay-up process. The article provides information on composite cure tooling that is fabricated from steel, aluminum, or high-temperature composite materials. The quality assurance for commercial applications is reviewed. The article concludes with a discussion on data fusion systems designed to provide nondestructive analysis data from fabrication and assembly processes for each individual composite part.
Lamina and Laminate Mechanical Testing
Authors: Wishart Rod
Published: December 2018

This article provides the general mechanical testing guidelines for the characterization of lamina and laminate properties. Guidelines are provided for tensile property, compressive property, shear property, flexure property, fracture toughness, and fatigue property test methods. The article also tabulates selected standards for lamina and laminate mechanical testing.
Element and Subcomponent Testing
Authors: Gintert Lawrence A.
Published: December 2018

This article explores why structural element and subcomponent testing are conducted. It discusses the different types of failure modes in composites, and provides information on the testing methodology, fixturing, instrumentation, and data reporting. The article reviews various standard elements used to characterize composite materials for the various failure modes. Simple structural-element testing under in-plane unidirectional, multidirectional, and combined loading, as well as out-of-plane loading are discussed. Simple bolted and bonded joints, as well as data correlation are reviewed with analytical predictions. The article also provides a list of the ASTM testing standards applicable at the element level of testing for both polymer-matrix composites and metal-matrix composites. It concludes with a discussion on durability and damage tolerance testing.
Rehabilitation of Reinforced Concrete Structures Using Fiber-Reinforced Polymer Composites
Authors: Zureick A. , Kahn L.
Published: December 2018

Rehabilitation is the process of repairing or modifying reinforced concrete structures to a desired useful condition. This article describes the operational steps for the structural assessment of reinforced concrete structures. It discusses the classification of composite materials reinforcing systems for strengthening reinforced concrete structures, such as shop-manufactured and field-manufactured structures. The article reviews the materials property requirements for designing reinforcing systems to strengthen the reinforced concrete structures. It discusses the fiber-reinforced polymer (FRP)-reinforced concrete behavior that depends on flexural, shear, or axial failures. Surface preparation procedures for rehabilitation techniques of reinforced concrete structures using bonded FRP materials are also discussed. The article provides information on the applications of rehabilitation of concrete structures. It explains data recording and acceptance criteria for rehabilitation of concrete structures with composite materials.
Introduction to Failure Analysis
Authors: Stumpff Patricia L.
Published: December 2018

This article provides a summary of the concepts discussed in the articles under the Section “Failure Analysis” in ASM Handbook, Volume 21: Composites. Most of the information in this Section is geared toward organic-matrix composites, although there is some information on failure analysis and fractography of ceramic- and metal-matrix composites.
Failure Causes
Authors: Moalli John E.
Published: December 2018

As with most engineering materials, the failure of composite materials, no matter how complex, can be divided into three discrete arenas: improper design, improper manufacturing, and improper use of the end product. This article reviews the failure causes from a broad perspective, so that the composites designer, manufacturer, and user can readily see some of the more common issues associated with unique materials. It discusses the three discrete arenas of failure of composite materials: improper design, improper manufacturing, and improper use of the end product.
Failure Analysis Procedures
Authors: Stumpff Patricia L.
Published: December 2018

This article describes the failure analysis procedures for composites and the techniques to be used in these analyses. These procedures include a review of the available in-service records, materials and processing methods, print requirements, and manufacturing records; visual analysis and nondestructive part evaluation; and verification of materials and processing methods. The article discusses the determination of fiber, matrix, and void volume fractions and verification of ply lay-up and orientation. A review of composites processing parameters; fractography and surface analysis; and mechanical testing and stress analysis is also presented.
Microscopy
Authors: Hayes Brian S. , Gammon Luther M.
Published: December 2018

Microscopy is a valuable tool in materials investigations related to problem solving, failure analysis, advanced materials development, and quality control. This article describes the sample preparation techniques of composite materials. These techniques include mounting, rough grinding, and polishing. The preparation techniques of ultrathin sections are also summarized. The article explains the illumination methods used by reflected light microscopy to view a specimen. These consist of epi-bright-field illumination, epi-dark-field illumination, epi-polarized light, and epi-fluorescence. The article also provides information on transmitted light microscopy.
Case Histories
Authors: Stumpff Patricia L.
Published: December 2018

This article describes the results of several case history studies of the failure of polymer-matrix composite components to provide not only some representative types of failures that can encounter, but also to provide some insight into the investigative process. These case histories deal mainly with structures that exhibit an initial material and/or manufacturing defect or failures that are most prevalent and most easily solved. The components include helicopter rotor blade, composite wing spar, and aircraft rudder.
Automotive Applications
Authors: Gianaris Nicholas J.
Published: December 2018

This article discusses the advantages of polymer matrix composite for automotive application in terms of design drivers, noise, vibration, harshness efficiency, process materials property constraints, safety and reliability, design optimization, structural and appearance requirements, recyclability, and processability. It describes the properties of high-volume composites used in automotive industries. The article provides a discussion on state-of-the-art and developing technologies in automotive field.
Introduction to Applications for Advanced Composites
Authors: Tolle Tia Benson , Hunt Warren H.
Published: December 2018

This article highlights the selected applications of advanced polymer-matrix composites, metal-matrix composites, and ceramic matrix composites.
Crystal-Plasticity Fundamentals
Authors: Piehler Henry R.
Published: December 2018

This article presents the Schmid's law that describes the response of crystal structures to loading. It describes the Taylor model to calculate the uniaxial yield stress of an isotropic face-centered cubic aggregate in terms of critical resolved shear stress. The article discusses the stress-based approach of the Bishop and Hill procedure to directly find stress states that could simultaneously operate at least five independent slip systems. It presents ways to find isostress or lower-bound yield loci for sheets having single-crystal orientation.
Modeling of Microstructure Evolution during Solidification Processing
Authors: Gandin Ch.-A. , Steinbach I.
Published: December 2018

This article focuses on the intermediate length scales, where transport phenomena govern the spatial and temporal evolution of a structure. It presents the cellular automaton (CA) and phase field (PF) methods that represent the state of the art for modeling macrostructure and microstructure. The article describes the principles of the PF method and provides information on the applications of the PF method. The CA model is introduced as a computationally efficient method to predict grain structures in castings using the mesoscopic scale of individual grains. The article discusses the coupling of the CA to macroscopic calculation of heat, flow, and mass transfers in castings and applications to realistic casting conditions.
Modeling of Microstructure Evolution during the Thermomechanical Processing of Titanium Alloys
Authors: Semiatin S.L. , Furrer D.U.
Published: December 2018

This article focuses on the modeling of microstructure evolution during thermomechanical processing in the two-phase field for alpha/beta and beta titanium alloys. It also discusses the mechanisms of spheroidization, the coarsening, particle growth, and phase decomposition in titanium alloys, with their corresponding equations.
Modeling of Nucleation Processes
Authors: Clouet Emmanuel
Published: December 2018

This article describes the results obtained by Volmer, Weber, Farkas, Becker, and Doring, which constitute the classical nucleation theory. These results are the predictions of the precipitate size distribution, steady-state nucleation rate, and incubation time. The article reviews a nucleating system as a homogeneous phase using the classical nucleation theory, along with heterophase fluctuations that led to the formation of precipitates. It discusses the gas cluster dynamics using the kinetic approach to describe nucleation. The article presents key parameters, such as cluster condensation and evaporation rates, to describe the time evolution of the system. The predictions and extensions of the classical nucleation theory are discussed. The article also provides the limitations of classical nucleation theories in cluster dynamics.
Phase-Field Microstructure Modeling
Authors: Shen Chen , Wang Yunzhi
Published: December 2018

This article discusses the fundamental aspects of phase-field microstructure modeling. It describes the evolution of microstructure modeling, including nucleation, growth, and coarsening. The article reviews two approaches used in the modeling nucleation of microstructure: the Langevin force approach and explicit nucleation algorithm. Calculation of activation energy and critical nucleus configuration is discussed. The article presents the deterministic phase-field kinetic equations for modeling growth and coarsening of microstructure. It also describes the material-specific model inputs, chemical free energy and kinetic coefficients, for phase-field microstructure modeling. The article provides four examples that illustrate some aspects of phase-field modeling.
Self-Consistent Modeling of Texture Evolution
Authors: Dye David
Published: December 2018

Self-consistent models are a particular class of models in continuum micromechanics, that is, the field concerned with making predictions of the properties and evolution of aggregates whose single-crystal deformation behavior is known. This article provides information on the measurement and representation of textures as well as prediction of texture evolution in single-phase materials and two-phase aggregates.
Modeling and Simulation of Cavitation during Hot Working
Authors: Nicolaou P.D. , Ghosh A.K. , Semiatin S.L.
Published: December 2018

This article focuses on the modeling and simulation of cavitation phenomena. It summarizes the experimental observations of cavitation and reviews the modeling of cavity nucleation and growth. The article discusses the modeling of the cavity growth based on mesoscale and microscale under uniaxial versus multiaxial tensile-stress conditions. Mesoscale models incorporate the influence of local microstructure and texture on cavitation. The article outlines the descriptions of cavity coalescence and shrinkage. It also describes the simulation of the tension test to predict tensile ductility and to construct failure-mechanism maps.
Crystal-Scale Simulations Using Finite-Element Formulations
Authors: Dawson P.R. , Boyce D.E.
Published: December 2018

This article provides an explanation on how crystal plasticity is implemented within finite element formulations by the use of physical length scales: crystal scale and continuum scale. It provides theoretical formulations for kinematic framework for deforming crystals and polycrystals, elastic and plastic behaviors of single crystals, refinements to the single-crystal constitutive, and crystal-scale finite-element. The article also presents examples that illustrate the capabilities of the formulations at the length scales.
Introduction to Fundamentals of Modeling for Metals Processing
Authors: Furrer D.U. , Semiatin S. L.
Published: December 2018

This article provides a brief historical perspective, a classification of metallurgical processes, basic model development efforts, and an overview of the potential future directions for the modeling of metals processing. It describes the classification of material behavior models, which can be grouped broadly into three classes: statistical, phenomenological, and mechanistic models. The article also presents an overview of the potential directions for the modeling of metals processing.
Integrated Computational Materials Engineering
Authors: Allison John E. , Li Mei , Su XuMing
Published: December 2018

Integrated computational materials engineering refers to the use of computer simulations that integrate mathematical models of complex metallurgical processes with computer models used in component and process design. This article outlines an example of a computer-aided engineering tool, such as virtual aluminum castings (VAC), developed and implemented for quickly developing durable cast aluminum power train components. It describes the procedures for the model development of the VAC system. These procedures include linking the manufacturing process to microstructure, linking microstructures to mechanical properties, linking material properties to performance prediction, and model validation and integration into the engineering process. The article discusses the benefits of the VAC system in process selection, process optimization, and improving the component design criteria.
Transport Phenomena during Solidification
Authors: Dantzig Jonathan A.
Published: December 2018

This article presents the governing equations for moving a solidification front, based on the balance of mass, momentum, energy, and solute. It reviews how material properties and geometry can be analyzed in the context of the governing equations. The article provides several example problems that illustrate how the hierarchy of time and length scales associated with transport leads to the important features of cast microstructures. It includes equations for estimating microsegregation in cast alloys.
Modeling Diffusion in Binary and Multicomponent Alloys
Authors: Morral John , Meisenkothen Frederick
Published: December 2018

This article presents various equations that are essential for the modeling of both single-phase and multiphase profiles. It includes the fundamental laws of diffusion, along with its equations and solutions. The article provides information on the series of applications that illustrate how various diffusional processes can be modeled.
Models for Fracture during Deformation Processing
Authors: Kuhn Howard
Published: December 2018

This article discusses physical analysis, including slab method and upper-bound method and slip-line field analysis, for calculating stress states in plastic deformation processes. It presents various validation standards and models for evaluating the criterion of fracture for use in finite-element analyses of deformation processing. The article reviews the Cockcroft-Latham criterion of fracture and its reformulated extension for analysing the fracture locus for compression. It concludes with information on fundamental fracture models.
Modeling and Simulation of Metal Powder Injection Molding
Authors: Ahn Seokyoung , Chung Seong-Taek , Park Seong Jin , German Randall M.
Published: December 2018

This article focuses on the axisymmetric 2.5-dimensional approach used in metal powder injection molding (PIM) simulations. It describes three stages of PIM simulations: filling, packing, and cooling. The article discusses the process features of numerical simulation of PIM, such as filling and packing analysis, cooling analysis, and coupled analysis between filling, packing, and cooling stages. It explains the experimental material properties and verification for filling, packing, and cooling stages in the PIM simulations. The article presents simulation results from some of the 2.5-dimensional examples to demonstrate the usefulness of the computer-aided engineering analysis and optimization capability of the PIM process.
Grain-Boundary Energy and Mobility
Authors: Gottstein G. , Molodov D.A. , Shvindlerman L.S.
Published: December 2018

Grain boundaries are interfaces between crystallites of the same phase but different crystallographic orientation. They can be characterized as being low angle or high angle. This article discusses the measurements of grain-boundary energy with a brief summary of different schemes for measuring grain-boundary surface tension. The atomistic simulations of grain-boundary energy, measurement of grain-boundary migration and the techniques used to monitor grain-boundary migration are reviewed. Several considerations and effects influencing the computation of grain-boundary mobility are also discussed.
Measurement and Interpretation of Flow Stress Data for the Simulation of Metal-Forming Processes
Authors: Semiatin S.L. , Altan T.
Published: December 2018

This article describes the most commonly used test methods for determining flow stress in metal-forming processes. The methods include tension, ring, uniform compression, plane-strain compression, torsion, split-Hopkinson bar, and indentation tests. The article discusses the effect of deformation heating on flow stress. It provides metallurgical considerations at hot working temperatures and presents flow curves at conventional metalworking strain rates. The article describes the effect of microstructural scale, crystallographic texture, and equiaxed phases on flow stress at hot working temperatures. It tabulates a summary of certain values describing the flow stress-strain rate relation for steels, aluminum alloys, copper alloys, titanium alloys, and other metals at various temperatures.
Modeling of Hot Isostatic Pressing
Authors: Samarov Victor , Goloveshkin Vassily
Published: December 2018

This article discusses the two major applications of hot isostatic pressing (HIP), such as healing of inherent internal defects in castings and welds, and consolidation of powder materials. It describes the design principles of the HIP tooling, as well as the problems associated with mathematical modeling of HIP. The article presents an example for the modeling process of the HIP. It reviews the numerical modeling and tooling design of a casing component demonstration.
Commercial Alloy Phase Diagrams and Their Industrial Applications
Authors: Zhang F. , Yang Y. , Cao W.S. , Chen S.L. , Wu K.S. , Chang Y.A.
Published: December 2018

This article focuses on the industrial applications of phase diagrams. It presents examples to illustrate how a multicomponent phase diagram calculation can be readily useful for industrial applications. The article demonstrates how the integration of a phase diagram calculation with kinetic and microstructural evolution models greatly enhances the power of the CALPHAD approach in materials design and processing development. It also discusses the limitations of the CALPHAD approach.
Modeling of Diffusion Bonding
Authors: Bampton C.C.
Published: December 2018

The goals of modeling diffusion bonding can be regarded as twofold: to optimize the selection of the process variables for a given material and to provide an understanding of the mechanisms by which bonding is achieved. This article describes the existing models of diffusion bonding with an assumption that the surfaces to be joined are free of contaminants and oxide, that bonding occurs between similar materials, and that the materials are single-phase metals. It discusses the mechanisms considered for diffusion bonding and limitations of existing models.
Simulation of Induction Heating Prior to Hot Working and Coating
Authors: Rudnev Valery
Published: December 2018

The most popular metal hot working processes for which induction heating is applied are forging, forming, extrusion, and rolling. This article focuses on estimation techniques to determine basic induction heating process parameters, including coil power, length of heating line, and frequency selection. It discusses three modes of heat transfer: conduction, convection, and radiation, in induction heating. The article describes the factors affected by a distortion of the magnetic field at the coil end through a schematic illustration of distribution of three magnetic force components experienced by the turns of the coil. It concludes with information on some case studies of numerical simulation.
Modeling and Simulation of Machining
Authors: Fischer Christian E.
Published: December 2018

This article begins with information on the fundamentals of chip formation process and general considerations for the modeling and simulation of machining processes. It focuses on smaller-scale models that seek to characterize the workpiece/tool/chip interface and behaviors closely associated with that. The article describes the advantages and disadvantages of various finite-element modeling approaches, namely, transient models, continuous cutting model, steady-state model, hybrid model, two-dimensional models, and three-dimensional models. It discusses flow stress measurements using constitutive and inverse testing methods and reviews tool design for chip removal. The article explains the effect of tool geometry on burr formation and the effect of coatings on tool temperatures. It concludes with information on tool wear, which is an unavoidable effect of metal cutting.
Modeling Sheet Shearing Processes for Process Design
Authors: Ghosh Somnath , Li Ming
Published: December 2018

This article discusses a set of experimental and computational studies aimed at understanding the effect of various processing parameters on the extent of burr and other defect formation during sheet edge-shearing and slitting processes. It describes the development of experimentally validated finite-element models for analyzing the classes of shearing processes. The article also discusses the use of microstructural characterization with stereology to render three-dimensional volumetric parameters. It concludes with information on the numerical simulation of an edge-shearing process, along with sensitivity studies with respect to process and tool parameters.
Heating and Heat-Flow Simulation
Authors: Wang Gang , Rong Yiming , Sisson Richard D.
Published: December 2018

This article provides information on the heat-source model, conduction heat-transfer model of parts and fixtures, and the radiation heat-transfer and convection heat-transfer models in a furnace. It describes the two types of furnaces used for heat treating: batch furnaces and continuous furnaces. The heating methods, such as direct-fired heating, radiant-tube heating, and electrical heating, are also discussed. Furnace temperature control is essential to ensure quality heat treatment. The article explains the operating procedure of the automatic temperature controllers used in most furnace operations. Heating simulations can be validated by comparison with measured results in full-scale furnaces. The article also presents several case studies to illustrate the use of the simulations.
Modeling of Powder Metallurgy Processes
Authors: Kuhn Howard
Published: December 2018

Power metallurgy (PM) is a process of shaping metal powders into near-net or net shape parts combined with densification or consolidation processes for the development of final material and design properties. This article introduces the general considerations, models, and applications in the modeling of PM processes. It describes the PM process in terms of powder compaction and sintering. The article schematically illustrates powder injection molding for the production of plastic parts and describes PM process models such as discrete-element model (DEM), linear continuum model, and nonlinear continuum model. It concludes with information on the application of press and sinter modeling to practical problems in PM.
Texture Measurement and Analysis
Authors: Rollett A.D.
Published: December 2018

This article discusses the central aspect of anisotropy modeling, namely, texture measurement and analysis. It provides an overview of the methods available for characterizing crystallographic preferred orientation, or texture, in polycrystalline materials. These methods include pole figure measurement and electron backscatter diffraction (EBSD). The article describes the process considerations for pole figure measurement, including X-ray diffraction, neutron diffraction, stereographic projection, equal area projection, graphing pole figures, typical textures, and orientation distribution. It also deals with the limitations and challenges associated with the EBSD, and applications of the diffraction.
Uncertainty Management in Materials Design and Analysis
Authors: Allen Janet K.
Published: December 2018

This article presents an approach to manage the uncertainty present in materials design. It describes inductive and deductive approaches to deal with uncertainty. The article focuses on providing an understanding of the opportunities for managing uncertainty and the decisions that influence the accuracy of the results. A design of experiments (DOE) represents a sequence of experiments to be performed, expressed in terms of factors set at specified levels. The article discusses the two types of DOEs: the full factorial design and the fractional factorial design. It explains the factors to be considered when selecting a procedure for propagating uncertainty. The article lists the categories of the popular types of uncertainty propagation methods, including simulation-based methods, local expansion methods, and numerical integration-based methods.
Introduction to Metals Process Simulation
Authors: Furrer D.U. , Semiatin S.L.
Published: December 2018

This article discusses process simulation applications such as casting, powder metallurgy, machining, surface engineering, heat treatment, and joining. The implementation of modeling and simulation tools requires accurate descriptions of material properties and process boundary conditions. The article describes the role of input data and boundary conditions for process simulations. It provides information on the critical enablers of computational materials engineering, such as the computational speed, computational materials engineering software/hardware supply chain, and cost structure for virtual versus physical manufacturing and analysis.
Applications of Medical Implant Materials
Authors: Drummond Colin K. , Hdeib Alia , Khan Fahd R.
Published: December 2018

The biocompatibility of a material relates to its immunological response, toxicity profile, and ability to integrate with surrounding tissue without undesirable local or systemic effects on a patient. This article underscores the transformation of the medical device design ecosystem engaged as an integral part of the device ecosystem. It discusses the applications of biomaterials, including orthopedic, cardiovascular, ophthalmic, and dental applications. The article describes four major categories of biomaterials such as metals, polymers, glass and ceramics, and composites. A discussion on natural materials, nanomaterials, and stem cells is also provided. The article concludes with examples of biomaterials applications, such as endovascular devices, knee implants, and neurostimulation.
Noble and Precious Metal Applications in Biomaterials with Emphasis on Dentistry
Authors: Roach Michael D. , Williamson Randall S. , Thomas Joseph A.
Published: December 2018

This article focuses on the use of noble and precious metals for biomedical applications. These include gold, platinum, palladium, ruthenium, rhodium, iridium, and osmium. The physical and mechanical properties of noble and precious metals are presented in tables. A brief discussion on the ancient history of noble and precious metal use in dentistry is provided. The article discusses the use of direct gold dental filling materials, direct silver dental filling materials, traditional amalgam alloys, high-copper amalgam alloys, and gallium alloys in biomedical applications. It also provides information on gold coatings and iridium oxide coatings for stents.