The purpose of this article is to assist the reader in understanding the role that an engineering expert witness plays in evaluating incidents related to product liability, so that he or she may become better acquainted with the role that an engineer plays in such litigation. The topics covered are admissibility of expert opinions, how to evaluate data, factual evidence, mandatory and voluntary standards, physical evidence, medical records, scientific literature, design decisions evaluation, environment of use, user's contribution, reports of opposing experts, report of findings, and deposition and trial testimonies.

This article discusses the three legal theories on which a products liability lawsuit is based and the issues of hazard, risk, and danger in the context of liability. It describes manufacturing and design defects of various products. The article explains a design that is analyzed from the human factors viewpoint and details the preventive measures of the defects, with examples. It presents four paramount questions relating to the probability of injury which are asked even when one executes all possible preventive measures carefully and thoroughly.

Failure analysis is the process used to determine the cause of a failure. There is no definitive method for performing a failure analysis, and the method chosen is dependent upon the type of failure, the availability of background information, the tools available to perform the analysis, and the skills of the analyst. The information outlined in this article focuses on the general methodology while allowing for case-specific techniques to be utilized along the way. It covers the causes of failure, why a failure analysis is performed, the failure analysis process, the planning of failure analysis investigation, recommendations to prevent the need for a failure analysis, the implementation of product reviews, and forensic standards.

As a failure investigation progresses, the time arrives when the data and results of the various testing and analyses are compiled, compared, and interpreted. Data interpretation should be relatively straightforward for results that align well. However, interpretation can be challenging when results from various tests seem contradictory or inconclusive. Regardless, conclusions must eventually be drawn from the data. This article discusses the processes involved in reviewing data, formulating conclusions, failure analysis report preparation and writing, and providing recommendations and follow-up with appropriate personnel to prevent future failures.

Mechanical properties of wire ropes, their chemical composition, and the failure analysis process for them are described. The wires are manufactured from high-carbon, plain carbon steel, with high-strength ropes most often manufactured from AISI Grade 1074. During visual failure examination, the rope, strand, and wire diameters should all be measured. Examination should also address the presence or absence of lubricant, corrosion evidence, and gross mechanical damage. Failed wires can exhibit classic cup-and-cone ductile features, flat fatigue features, and various appearances in-between. However, wires are often mechanically damaged after failure. Most nondestructive evaluation (NDE) techniques are not applicable to wire rope failures. Electron microscope fractography of fracture surfaces is essential in failure analysis. Fatigue is the most important fracture mode in wire ropes. Metallographic features of wire ropes that failed because of ductile overload and fatigue are described.

This article provides assistance to a failure analyst in broadening the initial scope of the investigation of a physical engineering failure in order to identify the root cause of a problem. The engineering design process, including task clarification, conceptual design, embodiment design, and detail design, is reviewed. The article discusses the design process at the personal and project levels but takes into consideration the effects of some higher level influences and interfaces often found to contribute to engineering failures.

This article briefly reviews the analysis methods for spalling of striking tools with emphasis on field tests conducted by A.H. Burn and on the laboratory tests of H.O. McIntire and G.K. Manning and of J.W. Lodge. It focuses on the metallography and fractography of spalling. The macrostructure and microstructure of spall cavities are described, along with some aspects of the numerous specifications for striking/struck tools. The article also describes the availability of spall-resistant metals and the safety aspects of striking/struck tools in railway applications.

Reliability-centered maintenance (RCM) is a systematic methodology for preventing failures. This article discusses the history of RCM and describes the key characteristics of an RCM process, which involves asking seven questions. The first four questions comprise a form of failure modes and effects analysis (FMEA), and therefore, the article explains the approach of RCM to FMEA and the failure management policies available under RCM. It reviews the ways that RCM classifies failure effects in terms of consequences and details how RCM uses failure consequences to identify the best failure management policy for each failure mode. The article concludes with a discussion on some practical issues pertaining to RCM that lie outside the scope of SAE JA1011.

Reliability-centered maintenance (RCM) is a systematic methodology for preventing failures. This article begins by discussing the history of RCM and uses Society of Automotive Engineers (SAE) all-industry standard JA1011 as its model to describe the key characteristics of an RCM process. It then expands on questions involved in RCM process, offering definitions when necessary. Next, the article describes the approach of RCM to failure modes and effects analysis (FMEA), the failure management policies available under RCM, and the criteria of RCM for deciding when a specific failure management policy is technically feasible. Then, after discussing the ways that RCM classifies failure effects in terms of consequences, it describes how RCM uses failure consequences to identify the best failure management policy for each failure mode. Next, the building blocks of RCM are put together to create a failure management program. The article ends with a discussion on some practical issues pertaining to RCM that lie outside the scope of SAE JA1011.

This article briefly introduces the concepts of failure analysis, including root-cause analysis (RCA), and the role of failure analysis as a general engineering tool for enhancing product quality and failure prevention. It initially provides definitions of failure on several different levels, followed by a discussion on the role of failure analysis and the appreciation of quality assurance and user expectations. Systematic analysis of equipment failures reveals physical root causes that fall into one of four fundamental categories: design, manufacturing/installation, service, and material, which are discussed in the following sections along with examples. The tools available for failure analysis are then covered. Further, the article describes the categories of mode of failure: distortion or undesired deformation, fracture, corrosion, and wear. It provides information on the processes involved in RCA and the charting methods that may be useful in RCA and ends with a description of various factors associated with failure prevention.

This article briefly introduces the concepts of failure analysis and root cause analysis (RCA), and the role of failure analysis as a general engineering tool for enhancing product quality and failure prevention. It reviews four fundamental categories of physical root causes, namely, design deficiencies, material defects, manufacturing/installation defects, and service life anomalies, with examples. The article describes several common charting methods that may be useful in performing an RCA. It also discusses other failure analysis tools, including review of all sources of input and information, people interviews, laboratory investigations, stress analysis, and fracture mechanics analysis. The article concludes with information on the categories of failure and failure prevention.

This article describes the underlying fundamentals, applications, the relevance and necessity of performing proper stress analysis in conducting a failure analysis. It presents an introduction to the stress analysis of bodies containing crack-like imperfections and the topic of fracture mechanics. The fracture mechanics approach is an important part of stress analysis at the tips of sharp cracks or discontinuities. The article reviews fracture mechanics concepts, including linear elastic fracture mechanics, elastic-plastic fracture mechanics, and subcritical fracture mechanics. It also provides information on the applications of fracture mechanics in failure analysis.

This article describes concepts and tools that can be used by the failure analyst to understand and address deformation, cracking, or fracture after a stress-related failure has occurred. Issues related to the determination and use of stress are detailed. Stress is defined, and a procedure to deal with stress by determining maximum values through stress transformation is described. The article provides the stress analysis equations of typical component geometries and discusses some of the implications of the stress analysis relative to failure in components. It focuses on linear elastic fracture mechanics analysis, with some mention of elastic-plastic fracture mechanics analysis. The article describes the probabilistic aspects of fatigue and fracture. Information on crack-growth simulation of the material is also provided.

On 14 April 1912, at 11:40 p.m., Greenland Time, the Royal Mail Ship Titanic on its maiden voyage was proceeding westward at 21.5 knots (40 km/h) when the lookouts on the foremast sighted a massive iceberg estimated to have weighed between 150,000 to 300,000 tons at a distance of 500 m ahead. Immediately, the ship’s engines were reversed and the ship was turned to port (left) in an attempt to avoid the iceberg. In about 40 sec, the ship struck the iceberg below the waterline on its starboard (right) side near the bow. The iceberg raked the hull of the ship for 100 m, destroying the integrity of the six forward watertight compartments. Within 2 h 40 min the RMS Titanic sank. Metallurgical examination and chemical analysis of the steel taken from the Titanic revealed important clues that allow an understanding of the severity of the damage inflicted on the hull. Although the steel was probably as good as was available at the time the ship was constructed, it was very inferior when compared with modern steel. The notch toughness showed a very low value (4 J) for the steel at the water temperature (-2 deg C) in the North Atlantic at the time of the accident.

This article focuses on the general methods and approaches from the perspective of a reconstruction analyst and includes discussions relevant to materials failure analysts at the incident scene. The elements of accident reconstruction are described. These have conceptual similarity with the principles for failure analysis of material incidents that are less complex than a large-scale accident. The article provides a brief review of some general concepts on the use of modeling which can be a very powerful tool for information pertaining to the reconstruction of an accident where the model can be a physical, mathematical, or logical representation of a physical system or process.

Failure analysis is generally defined as the investigation and analysis of parts or structures that have failed or appeared to have failed to perform their intended duty. Methods of field inspection and initial examination are also critical factors for both reconstruction analysts and materials failure analysts. This article focuses on the general methods and approaches from the perspective of a reconstruction analyst. It describes the elements of accident reconstruction, which have conceptual similarity with the principles for failure analysis of material incidents that are less complex than a large-scale accident. The approach presented is that the analysis and reconstruction is based on the physical evidence. The article provides a brief review of some general concepts on the use and limitations of advanced data acquisition tools and computer modeling. Legal implications of destructive testing are discussed in detail.

This article describes the methodology for performing a failure modes and effects analysis (FMEA). It explains the methodology with the help of a hot water heater and provides a discussion on the role of FMEA in the design process. The article presents the analysis procedures and shows how proper planning, along with functional, interface, and detailed fault analyses, makes FMEA a process that facilitates the design throughout the product development cycle. It also discusses the use of fault equivalence to reduce the amount of labor required by the analysis. The article shows how fault trees are used to unify the analysis of failure modes caused by design errors, manufacturing and maintenance processes, materials, and so on, and to assess the probability of failure mode occurrence. It concludes with information on some of the approaches to automating the FMEA.

There are many reasons why plastic materials should not be considered for an application. It is the responsibility of the design/materials engineer to recognize when the expected demands are outside of what the plastic can provide during the expected life-time of the product. This article reviews the numerous considerations that are equally important to help ensure that part failure does not occur. It provides a quick review of thermoplastic and thermoset plastics. The article focuses primarily on thermoset materials that at room temperature are below their glass transition temperature. It describes the motivation for material selection and the goal of the material selection process. The use of material datasheets for material selection as well as the processes involved in plastic material selection and post material selection is also covered.

This article focuses on the mechanisms of microbiologically influenced corrosion as a basis for discussion on the diagnosis, management, and prevention of biological corrosion failures in piping, tanks, heat exchangers, and cooling towers. It begins with an overview of the scope of microbial activity and the corrosion process. Then, various mechanisms that influence corrosion in microorganisms are discussed. The focus is on the incremental activities needed to assess the role played by microorganisms, if any, in the overall scenario. The article presents a case study that illustrates opportunities to improve operating processes and procedures related to the management of system integrity. Industry experience with corrosion-resistant alloys of steel, copper, and aluminum is reviewed. The article ends with a discussion on monitoring and preventing microbiologically influenced corrosion failures.