This article provides guidelines for the assessment of model quality in materials science and engineering. It discusses the fundamentals of model quality assessment and the calibration of mechanistic material models. The article reviews the considerations for the model verification during software implementation planning to identify suitable programs, software components, and programming languages. It describes the validity tests used in model validation, including boundary-value tests, degenerate problem tests, sensitivity tests, and benchmarking. The article also presents an example of model calibration, verification, and validation for the prediction of martensite start temperature of steels.

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.

Modeling will help reduce machining problems and thereby enable more rapid introduction of high-performance materials and components. This article discusses the technical needs of aircraft engine and airframe structural components and modeling of heat-treat-induced residual stress by finite-element residual-stress analysis. It describes the two-dimensional (2-D) and three-dimensional (3-D) procedures involved in finite-element residual-stress analysis. The article deals with the 2-D and 3-D machining distortion validation on engine-disk-type components. It describes methods for obtaining machining-induced residual stresses, including detailed finite-element analysis of the cutting process, the simple fast-acting mechanistic model, and the semi-empirical linear stress model. The article concludes with information on the modeling benefits and implementation of modeling in a production environment.

Fusion welding processes involve four phase changes, namely, solid-solid state, solid-liquid, liquid-vapor, and vapor-plasma. Each has its own thermal, momentum, and stress history. This article discusses some important techniques to validate temperature, momentum, stress, and residual strain history observed in the heat-affected zone of fusion welded materials.

This article provides a detailed overview of the thermomechanical modeling of additive manufacturing (AM) process. It begins with information on a basic understanding of the formation of residual stress during AM processing followed by a discussion on models commonly applied in AM modeling, such as heat-input models, material models, and material activation models. Information on experimental setup for validation and simulation of directed-energy deposition model is then included. The article also provides information on moving-source and part-scale analyses to simulate the laser powder-bed fusion AM process.

This article focuses on the necessary basics for thermomechanical fusion welding simulations and provides an overview of the specific aspects to be considered for a simulation project. These aspects include the required material properties, experimental data needed for validation of the simulation results, simplifications and assumptions as a prerequisite for modeling, and thermomechanical simulation. The article concludes with information on the sensitivity of the material properties data with respect to the simulation results. It also provides hints on the central challenge of having the right material properties at hand for a specific simulation task.

This article provides information on the boundary conditions that must be applied to model the heat-transfer coefficient (HTC) in a component being cooled. It describes the historical perspective of various experiments to determine the HTCs. Computational fluid dynamics codes have also been used to predict the HTCs around a part. The article provides information on the various modeling studies used to predict cooling rates in a component. The prediction of residual stresses by validation and optimization of residual stress models is also discussed. Several techniques, such as models neglecting and incorporating material transformation effects, used to predict residual stresses are reviewed. The article also explains the various aspects of models used to prevent cracking during heating and quenching.

The misorientation of a boundary of a growing grain is defined not only by its crystallography but also by the crystallography of the grain into which it is growing. This article focuses on the Monte Carlo Potts model that is typically used to model grain growth, Zener-Smith pinning, abnormal grain growth, and recrystallization. It introduces the basics of the model, providing details of the dynamics, simulation variables, boundary energy, boundary mobility, pinning systems, and stored energy. The article explains how to incorporate experimental parameters and how to validate the model by comparing the observed behavior quantitatively with theory. The industrial applications of the model are also discussed. The article also provides a wide selection of the algorithms for implementing the Potts model, such as boundary-site models, n -fold way models, and parallel models, which are needed to simulate large-scale industrial applications.

Modeling of gas evolution during sand mold castings is one of the most important technical and environmental issues facing the metal casting industry. This article focuses on describing the capability of numerically predicting gas evolution for the furan binder/silica sand system. It illustrates numerical modeling to study the gas evolution from furan binder/silica sand mold aggregate for aluminum, cast iron, and steel alloy cast components. The article discusses simulation results and experimental validation for aluminum alloys, cast iron castings, and steel alloys, as well as a parametric study that investigated the effects of various variables. It concludes with information on the application of 3-D modeling methodology to investigate gas emissions in furan binder/silica sand castings for steel 4140 and aluminum A356 alloys.

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.

Mathematical models have been used for over five decades in industrial heat-treating operations. Most of these modeling efforts have emanated from academia or research institutes, with the primary approach of mathematically capturing heat-treating processes and validating quality predictions. In this article, a contrarian but more realistic scenario is considered, where two industrial problem descriptions become the starting point. The technical complexity of the industry problem has been elaborated for a deeper understanding of the issue along with elaboration of the approach and potential methods for determining a solution. Then, quantitative analyses of practical industrial problems are demonstrated. Finally, the potential shift in these approaches with the advent of Industry 4.0 is outlined.

This article describes the types of closure mechanisms, including plasticity-induced, roughness-induced, oxide-induced, and fretting-debris-induced. It discusses test techniques used to establish a valid threshold value for aluminum alloy crack growth thresholds, steel crack growth thresholds, and titanium alloy crack growth thresholds. The near-threshold behavior of nickel-base superalloys is described. The article briefly reviews the threshold results for fiber-reinforced, whisker-reinforced, and particulate-re-inforced metal-matrix alloys. It explains the near-threshold fatigue crack propagation in welded joints and the fundamental considerations for modeling threshold behavior. The article concludes with a discussion on the effects of thresholds in the engineering design process.

The objective of dimensional management is to create a design and process that absorbs as much variation as possible without affecting the function of the product. This article describes the steps followed by the dimensional management process. These include defining product dimensional requirements, determining process and product requirements, ensuring accurate documentation, developing a measurement plan that validates product requirements, establishing manufacturing capabilities versus design intent, and establishing production-to-design feedback loop. The article discusses the simulation model in terms of a functional feature product model, component part variation, assembly method variation, measurement schemes, and assembly sequences.

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.

This article provides information on the classification of various composites manufacturing processes based on similar transport processes. The composites manufacturing processes can be grouped into three categories: short-fiber suspension methods, squeeze flow methods, and porous media methods. The article presents an overview of the modeling philosophy and approach that is useful in describing composite manufacturing processes.