Most modern instrumental techniques produce an output or signal that is not absolute. To obtain quantitative information, the raw output from an instrument must be converted into a physical quantity. This is done by standardizing or calibrating the raw response from an instrument and subsequently analyzing the uncertainty from both the calibration process and the measurement process. This article briefly summarizes the most common calibration and uncertainty analysis methods, namely external standard methods, abbreviated external standard methods, internal normalization, internal standard, standard addition, and serial dilution methods. In addition, it includes information on the traceability of true value of a measured quantity.

Probability of detection (POD) assesses the performance of a non-destructive evaluation (NDE)-based inspection, which is a method used to determine the capability of an inspection as a function of defect type and defect size. This article provides an overview of the concept of POD, why it is needed, the history behind the development of POD, how POD assessments are performed, and how modeling and simulation can be integrated into the execution of a POD assessment. It describes the methods by which POD is determined. This includes detail on the experimental process to acquire the needed data, the mathematical methods to obtain a POD curve, and techniques to assess uncertainty in the POD curve as it is obtained from a limited data set. The concept of model-assisted POD (MAPOD) is introduced, with additional details and representative examples of MAPOD.

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.

Neural networks permit the discovery of fundamental relationships and quantitative structure within vast arrays of ill-understood data. This article provides an overview of neural network modeling method, describing its overfitting nature. It discusses the use of neural networks in modeling noise and uncertainties in conducting experiments. The article also presents examples of the application of neural-network modeling to the behavior of metals.

The measurement of thermophysical properties of metal alloys, especially at high temperatures, is difficult because of the reactivity of some alloys. This article reviews the methods available for measurement of thermal and other physical properties for liquid, semi-solid, and solid commercial alloys, including adiabatic calorimetry, modulated calorimetry, Calvet calorimetry, single-pan calorimetry, and drop calorimetry. It describes differential scanning calorimetry and differential temperature analysis for measuring transition temperatures such as phase transformation or glass transition temperatures. The article schematically illustrates the laser flash apparatus for measuring the thermal diffusivity of solids and oscillation viscometer for measurements of the viscosity of metals. A summary of the measurement methods is presented in tables.

This article provides an outline of the issues to consider in performing a probabilistic life assessment. It begins with an historical background and introduces the most common methods. The article then describes those methods covering subjects such as the required random variable definitions, how uncertainty is quantified, and input for the associated random variables, as well as the characterization of the response uncertainty. Next, it focuses on specific and generic uncertainty propagation techniques: first- and second-order reliability methods, the response surface method, and the most frequently used simulation methods, standard Monte Carlo sampling, Latin hypercube sampling, and discrete probability distribution sampling. Further, the article discusses methods developed to analyze the results of probabilistic methods and covers the use of epistemic and aleatory sampling as well as several statistical techniques. Finally, it illustrates some of the techniques with application problems for which probabilistic analysis is an essential element.

This article examines the factors influencing the fatigue behavior of an individual weldment, using extensive experimental data and a computer model, which simulates the fatigue resistance of weldments. It discusses the process of fatigue in weldments. The service conditions, which favor long crack growth and the conditions, which favor crack nucleation are contrasted. The article presents experimental data, which is used to show the effect of weldment geometry on fatigue resistance. Several useful geometry classification systems are compared. The article analyzes a computer model, which is employed to investigate the behavior of two hypothetical weldments, namely, a discontinuity-containing weldment and a discontinuity-free weldment.

This article primarily considers the problem of sampling bulk materials, including minerals, metals, environmentally important substances, and industrial raw materials and waste products. It provides useful information on sample types, sampling plan, optimizing sampling resources, practical aspects of sampling, and how to ensure the quality of sampling.

This article is a detailed account of the principles of electron-excited X-ray microanalysis. It begins by discussing the physical basis of electron-excited X-ray microanalysis and the advantages and limitations of energy dispersive spectrometry (EDS) and wavelength dispersive spectrometry for electron probe microanalysis. Key concepts for performing qualitative analysis and quantitative analysis by electron-excited X-ray spectrometry are then presented. Several sources that lead to measurement uncertainties in the k-ratio/matrix corrections protocol are provided, along with the significance of the raw analytical total. Sections on accuracy of the standards-based k-ratio/matrix corrections protocol with EDS and processes of analysis when severe peak overlap occurs are also included. The article provides information on low-atomic-number elements, iterative qualitative-quantitative analysis for complex compositions, and significance of standardless analysis in the EDS software. It ends with a section on the processes involved in elemental mapping for major and minor constituents.

This article discusses some of the statistical aspects of design from an engineer's perspective. It reviews the commonly used statistical terms and distributions for providing some guidance on the practical engineering applications of these distributions. The article describes the basic statistical procedures that can be used to address variability and uncertainty in an engineering analysis. It contains a table that lists the relevant statistics standards published by the American Society of Testing and Materials.

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.

Hardness characterizes the resistance of the ceramic to deformation, densification, displacement, and fracture. It is usually measured with conventional microindentation hardness machines using the Knoop or the Vickers diamond indenters. This article discusses the metrology issues of the Knoop and the Vickers hardness in ceramics. It explicates how to estimate fracture toughness from Vickers indentation cracking. The article also provides information on instrumented hardness testing and the Meyer law.

The process of optimization involves choosing the best solution from a pool of potential candidate solutions. This article provides a description of some classes of problems and the optimization methods that solve them. These problems include the deterministic single-objective problem, the deterministic multiobjective problem, and the nondeterministic, stochastic optimization problem. The article presents several complementary approaches to solve a wide variety of single-objective and multiobjective mechanical engineering applications. Multiobjective optimization study and stochastic optimization studies are also discussed.

This article provides a schematic illustration of factors that should be considered in component design. It discusses the effect of component geometry on the behavior of materials and groups the main parameters that affect the value of the factor of safety. The article illustrates the estimation of probability of failure with an example. It reviews the designing and selection of materials for static strength and stiffness. The article also describes the causes of failure of engineering components, including design deficiencies, poor selection of materials, and manufacturing defects.

This article focuses on the specific features of carbon steels and alloy steels that are pertinent to heating by induction for warm and hot working processes. It provides a detailed account of the effects of various microstructures on austenitization kinetics for AISI 1045 steels. The article explains the factors to be considered for induction heating of various steel alloys. It describes the temperature and compositional issues that should be considered in the forging of steels that are induction heated.

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.

A phase diagram is a graphical representation of the phase equilibria of materials in terms of temperature, composition, and pressure. This article provides an overview on the background of phase diagram calculation software. It presents an algorithm to calculate binary stable phase equilibria. The article summarizes a rapid method to obtain a thermodynamic description of a multicomponent system. It also provides information on thermodynamically calculated phase diagrams.

This article presents typical problems encountered in the analysis of experimental creep and creep-rupture data and the possible solutions to these drawbacks. It provides information on planning the test and creep strain/time relationships. The exponential creep equation and the rational polynomial creep equation are discussed. The article also describes the dependence of stress and temperature on equation parameters and explains the lot-centered regression analysis.