This article describes the historical background, uncertainties in structural parameters, classifications, and application areas of probabilistic analysis. It provides a discussion on the basic definition of random variables, some common distribution functions used in engineering, selection of a probability distribution, the failure model definition, and a definition of the probability of failure. The article also explains the solution techniques for special cases and general solution techniques, such as first-second-order reliability methods, the advanced mean value method, the response surface method, and Monte Carlo sampling. A brief introduction to importance sampling, time-variant reliability, system reliability, and risk analysis and target reliabilities is also provided. The article examines the various application problems for which probabilistic analysis is an essential element. Examples of the use of probabilistic analysis are presented. The article concludes with an overview of some of the commercially available software programs for performing probabilistic analysis.

This article provides a brief introduction to neutron diffraction as well as its state-of-the-art capabilities. The discussion covers the general principles of the neutron, neutron-scattering theory, generation of neutrons, types of incident radiation, and purposes of single-crystal neutron diffraction, powder diffraction, and pair distribution function analysis. The relationship between detector space and reciprocal space are presented. Various factors involved in sample preparation, calibration, and techniques used for analyzing diffraction data are described. The article also presents application examples and possible future developments in neutron diffraction.

This article discusses pressure vessels, piping, and associated pressure-boundary items of the types used in nuclear and conventional power plants, refineries, and chemical-processing plants. It begins by explaining the necessity of conducting a failure analysis, followed by the objectives of a failure analysis. Then, the article discusses the processes involved in failure analysis, including codes and standards. Next, fabrication flaws that can develop into failures of in-service pressure vessels and piping are covered. This is followed by sections discussing in-service mechanical and metallurgical failures, environment-assisted cracking failures, and other damage mechanisms that induce cracking failures. Finally, the article provides information on inspection practices.

This article discusses corrosion fatigue, its effects on the damage tolerance of aircraft, and its predictive modeling. A conceptual framework is presented that incorporates two distinctive cyclic-based life-prediction philosophies and expands them both to include the time domain in order to consider the effects of corrosion. These philosophies include crack initiation used for safe-life design and crack growth used for damage tolerance. The article presents the methodology for computing the effects of real-time age degradation on an aircraft structure for two different corrosion types: crevice and pitting corrosion. It describes the rationale and techniques needed to apply the age-based structural integrity processes to in-service structures in order to realize the benefits throughout the full structural life cycle.

Supercritical water oxidation (SCWO) is an effective process for the destruction of military and industrial wastes including wastewater sludge. This article discusses the unique properties of supercritical water and lists the main technological advantages of SCWO. For many waste streams, corrosion continues to be one of the central challenges to the full development of the SCWO technology. The article presents a summary of selected materials exposed to various environments as well as the observed form of corrosion in a table. It also illustrates the necessity to adopt a synergistic approach incorporating feed chemistry control, reactor design modifications, and intelligent materials selection, for mitigating degradation of SCWO systems.

This article provides information on life assessment strategies and conceptually illustrates the interplay of nondestructive evaluation (NDE) and fracture mechanics in the damage tolerant approach. It presents information on probability of detection (POD) and probability of false alarm (PFA). The article describes the damage tolerance approach to life management of cyclic-limited engine components and lists the commonly used nondestructive evaluation methods. It concludes with an illustration on the role of NDE, as quantified by POD, in fully probabilistic life management.

This article presents a discussion on the U.S army's position on corrosion control for wheeled tactical vehicles. It addresses the army requirement for corrosion control. The U.S. Army Tank-automotive and Armaments Command (TACOM) defines the corrosion prevention and control requirements in the procurement document. The article summarizes requirements from a procurement document. As required by the procurement contract, corrosion-control technologies used in a vehicle system need to be evaluated to determine their benefit. The article provides information on testing systems, which help to meet the army's needs. It includes information on supplemental corrosion protection, which improves the corrosion resistance of a material.

Microwave and guided wave (GW) nondestructive evaluation (NDE) techniques are capable of detecting corrosion damage, cracks, and other defect types in inaccessible areas. This article describes the operation principles of the techniques and provides information on hidden corrosion detection and the applications of microwave NDE devices and GW ultrasonic NDE devices.

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 discusses the definitions, classifications, structural features, vapor pressure values, corrosion inhibition mechanisms, and methods of evaluation of vapor-phase-corrosion inhibitors or volatile corrosion inhibitors (VCIs). Practical methods of using VCIs for corrosion protection of aluminum, ferrous, and nonferrous alloys are discussed with specific examples. The article contains tables that summarize the applications of different VCIs used for protecting ferrous metals, copper and its alloys, and silver.

Selective plating, also known as brush plating, differs from traditional tank or bath plating in that the workpiece is not immersed in a plating solution (electrolyte). Instead, the electrolyte is brought to the part and applied by a handheld anode or stylus, which incorporates an absorbent wrapping for applying the solution to the workpiece (cathode). This article focuses on the selective plating systems that include a power pack, plating tools, anode covers, specially formulated plating solutions, and any auxiliary equipment required for the particular application. It provides a detailed account of the applications of selective plating, with examples. The article describes the advantages, limitations, key process elements, and health and safety considerations of selective plating. It also includes the most important industrial, government, and military specifications.

This article focuses on alternatives to chromium in both hard chromium plating and chromate conversion coating. These include electroless nickel plating, nickel-tungsten composite electroplating, spray coating applications, and cobalt/molybdenum-base conversion coating. The article discusses the material and process substitutions that can be used to eliminate the use or emissions of chromium in industrial processes. It describes the physical characteristics of each coating, economics, environmental impacts, advantages, and disadvantages of alternative processes.

From the standpoint of corrosion protection of iron and steel, metallic coatings can be classified into two types: noble coatings and sacrificial coatings. This article focuses on hotdipped zinc, aluminum, zinc-aluminum alloy and aluminum-zinc alloy coatings. It discusses the Sendzimir process and the Cook-Norteman process, which are the two commercial processes that are used for almost all hot-dip galvanized sheet steel in the United States. The article provides a discussion on the aqueous corrosion and atmospheric corrosion of galvanized steel and aluminized steel, as well as the intergranular corrosion of galvanized steel.

The success of a reliable non-destructive evaluation (NDE) application depends greatly on the expertise and thoroughness of the NDE engineering that is performed. This article discusses the general considerations of NDE in terms of NDE response and NDE system management and schedule. It describes the NDE engineering and NDE process control, along with some case studies related to the applications of NDE. The article reviews various models for predicting NDE reliability, such as ultrasonic inspection model, eddy current inspection model, and radiographic inspection model. It concludes with an example that illustrates the integration of an ultrasonic reliability model with a CAD system.

This article discusses the effects of brazing temperature and thermal treatment on structure and mechanical behavior of different classes of titanium base metals such as commercially pure (CP) titanium, alpha or near-alpha alloys, alpha-beta alloys, and beta alloys. The classification, properties, and potential heat treatment of titanium base alloys are presented in tables. The article provides information on brazed joints of titanium with carbon steels, as well as ceramics and graphite. It discusses the risks involved in titanium brazing, including erosion of base metal, brittle intermetallics, and low ductility. The article reviews induction and torch brazing, infrared brazing, diffusion brazing, and brazing by heating with ion bombardment. It concludes by describing the design criteria and limitations of brazing.

Crevice corrosion involves three fundamental types of processes such as electrochemical reactions, homogeneous chemical reactions, and mass transport. This article describes the critical factors of crevice corrosion, including crevice geometry, material, environment, crevice corrosion stifling, and pitting relationships. It explains the crevice corrosion of stainless steel, nickel alloys, aluminum alloys, and titanium alloys with examples. The article reviews the types of testing methods that have been developed for differentiating and ranking the resistance of alloys toward crevice corrosion. It also presents the strategies for the prevention of crevice corrosion or lessening its effects, such as design awareness, use of inhibitors, and electrochemical control methods.

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.

A detailed fracture mechanics evaluation is the most accurate and reliable prediction of process equipment susceptibility to brittle fracture. This article provides an overview and discussion on brittle fracture. The discussion covers the reasons to evaluate brittle fracture, provides a brief summary of historical failures that were found to be a result of brittle fracture, and describes key components that drive susceptibility to a brittle fracture failure, namely stress, material toughness, and cracklike defect. It also presents industry codes and standards that assess susceptibility to brittle fracture. Additionally, a series of case study examples are presented that demonstrate assessment procedures used to mitigate the risk of brittle fracture in process equipment.

Tungsten, molybdenum, and cemented carbide parts can be produced using several additive manufacturing technologies. This article classifies the most relevant technologies into two groups based on the raw materials used: powder-bed methods, such as selective laser melting, electron beam melting, and binder jet three-dimensional (3-D) printing, and feedstock methods, such as fused-filament fabrication and thermoplastic 3-D printing. It discusses the characteristics, processing steps, properties, advantages, limitations, and applications of these technologies.

This article focuses on the use of electron beam (EB) for near-net shape processing based on the wire feed material-delivery method. EB deposition processes start with a 3-D model designed in a computer-aided design (CAD) environment, where the deposition path and process parameters are generated. The article provides a description of the electron beam direct manufacturing (EBDM) system used for manufacturing of target parts with the aid of a case study. The control of the essential variables of dynamic beam deflection is also reviewed. The article also includes information on the applications of high-frequency multibeam processes, namely, selective surface treatment, multiple-pool welding, and pre- and post-heat treating.