ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2025 27 Imagine the consequences of that decision if there had been field failures with personal injury because of failed fasteners that this mechanic had compromised by not being properly trained and those concerns were not presented or investigated. No one would want to be on the receiving end of those hard questions. A TEAM EFFORT IS REQUIRED A properly conducted failure investigation is always a team effort that embraces input from multiple disciplines. As observed in the previous scenario, even the simplest failure investigation requires that the failure analyst have input from at least one other individual making the process a team effort, even just a team of two. The nature of the failure and the evolution of the investigation will determine which areas of expertise and assistance are required. KEY PARTICIPANTS IN THE INVESTIGATION PROCESS There are a few primary groups or departments that are most likely to assist in a failure investigation process, and each has a specific role. These include metallurgical/materials engineering, product engineering, quality assurance and quality engineering, and additional sources. Metallurgical and Materials Engi- neering. The input from the materials engineering/metallurgical department either in house or from an independent lab is always required for a successful failure investigation. This is the group or individual who has the skill set to identify the failure mode that is the starting point of all failure investigations. In addition to identifying the failure mode, the materials engineering department is generally tasked with determining the failed component’s compliance to material and processing specifications. There are many tests and standards utilized to verify a component’s properties and identification of the failure mode. Product Engineering. The product engineering department provides data regarding the initial design requirements of the component(s) in question and is an excellent source to evaluate effects of the design application. There are literally dozens of product engin- eering software tools available to model and verify design and application parameters of products. Including the product engineering department or an independent engineering consultant is an excellent addition to the investi- gative team. Product Engineering Test Lab. In addition to and complementary with product engineering input in the investigation, a product engineering test lab can provide vital information regarding a component’s expected life based on testing to standard parameters and anticipated operational loads. Quality Assurance and Quality Engineering. The quality assurance (QA) group must also be included in the investigative process. The QA group can provide vital information on product specifications, compliance with specifi- cations, product history, product issues and concerns, supplier historical performance and issues, and a host of other product and manufacturing data. The quality engineering group is generally part of the quality assurance COLLAPSE OF SILVER BRIDGE An example of a complex failure can be seen in the collapse of the Silver Bridge, which spanned the Ohio River between Point Pleasant, West Virginia and Gallipolis, Ohio. On December 15, 1967, the bridge collapsed during heavy rush-hour traffic. The tragedy caused 46 deaths. Ten months after the event, a preliminary investigation of the wreckage found the failure of a single eyebar in one of the suspension chains as the primary cause. More time was needed to uncover further evidence and complete a thorough investigation to explain why that eyebar failed. It would be three years before the final report was delivered. The ultimate determination was that a small crack formed through fretting wear at the bearing. Stress corrosion cracking caused the crack to grow. But it was only 0.1 inches (2.5 mm) deep, when the link failed. The collapse led to significant changes in the way bridges in the U.S. are inspected and maintained. Example of a catastrophic failure that was initiated from a relatively small flaw. Courtesy of Wikipedia.
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