What are the key steps and tools for conducting a forensic failure analysis of a product or component?

Proper handling and storage of failed samples prevent contamination and tempering of evidence which could compromise the accuracy of the failure analysis. Contamination can occur from environmental factors, handling by unauthorized individuals, or improper storage conditions. By preserving evidence in its original state, forensic analysts can accurately identify the root causes of failure as well as it can be confidently presented in legal proceedings as proof of liability or innocence. It provides a solid foundation for expert testimony and strengthens the case's credibility in court.

In my extensive experience, prioritizing evidence collection and preservation is paramount in forensic failure analysis. Advising clients to preserve samples prevents secondary damages that could complicate analysis. Additionally, obtaining a detailed service environment history is crucial. For instance, in an aerospace component investigation, knowing it was stored near a seaside warehouse revealed corrosion issues. Preserving evidence post-analysis, especially in court-related cases, is essential. Proper handling and storage, as highlighted by experts, ensure accurate analysis results and enhance credibility in legal proceedings. Meticulous preservation practices uphold evidence integrity throughout the analysis process.

Visual inspection of failed part involves documenting the as-recieved condition of the failed component through high resolution digital photographs, schematic sketches, or written descriptions of sequence of events. This documentation might serve as valuable evidence for further analysis and could be used to support findings in reports or legal proceedings. Visual inspection allows analysts to assess the material properties (and external factors) of the failed component, such as texture, color, surface finish, improper installation, operational misuse, or environmental conditions as well as presence of surface anomalies. These observations can provide insights into the material's condition, quality, and potential manufacturing defects.

In forensic analysis, visual inspection plays a pivotal role in assessing component condition. Utilizing the naked eye or magnifying glass, inspectors observe macro features like fracture surface smoothness, corrosion appearance, and distortion, providing initial insights into failure causes. This observation guides further investigation. Documenting the component's condition through photographs or descriptions is crucial evidence for analysis and supports findings in reports or legal proceedings. Inspection enables analysts to evaluate material properties, identify defects, and assess external factors, providing a comprehensive understanding of failure mechanisms.

In forensic analysis, non-destructive testing (NDT) is not as frequently utilized as in field inspections where components are in service. However, there are situations where NDT proves essential. For instance, in an industry case, we employed Ultrasonic testing to assess thickness loss in tubes, determining material loss rates and identifying areas of maximum loss. Similarly, Radiography revealed internal cracks in a large welded pipe. Although less common in forensic analysis, expertly applied NDT methods like ultrasonic, radiographic, magnetic, or thermal testing can still provide valuable insights into failure origins, mechanisms, and propagation when required.

Please make sure to do NDT only if it is required. If the damage in the failed part is due to corrosion then I would suggest not to conduct any NDT at the damage area otherwise the elemental chemistry of the deposits and other evidence will be Contaminated and root cause may be compromised.

Destructive testing like mechanical testing of the failed part is primarily done to check if the failed component meets the materials properties as per material specification or grade. If the manufacturing test mill certificate values are not in line with the mechanical test values which failure analyst get on failed part then it is improper material slipped into the assembly. Similarly mechanical properties by destructive testing like hardness values helps to do the structure property corelation in understanding the correctness of the heat treatment of the material.

In forensic analysis, performing destructive testing is a crucial step. DT methods such as tensile, hardness, fatigue, or impact testing provide valuable insights into mechanical properties and failure mechanisms. For instance, mechanical testing like tensile testing helps determine material properties like ductility and strength at the time of failure. This aids in supporting microstructural evidence, especially in cases of embrittlement due to environmental exposure. Additionally, hardness testing offers a quick estimate of material properties. By applying controlled loads, stresses, or strains, DT helps evaluate our hypotheses about failure causes, modes, and mechanisms, contributing to a comprehensive forensic analysis.

Analysis of lab test results aids in identifying the root cause of failure by pinpointing the factors or conditions that contributed to the observed behavior of the failed part. This may involve correlating material properties, design features, manufacturing processes, or external influences with failure outcomes. Analyzing lab test data and test results is a critical step in forensic failure analysis, which provide the empirical basis for understanding failure or damage mechanisms, identifying root causes, and recommending preventive measures.

In forensic failure analysis, analyzing the data and results from tests; destructive, non-destructive, and microscopic is pivotal. These results often appear disparate, requiring meticulous correlation to uncover the precise cause of failure. This analytical process serves as the final stage in determining the root cause. Expertly analyzing lab test data aids in identifying failure origins by correlating material properties, design features, manufacturing processes with observed behavior. This empirical approach forms the foundation for understanding failure mechanisms, pinpointing root causes, and proposing preventive measures.

This being a viral step, it is important to take care of following points; 1)Clearly defined failure statement including background.It should at the least include reference numbers of the failed system (e.g. engine/compressor/excavator/aeroplane/any other equipment), the number of hours of service at the time of failure, scheduled maintenance work carried out on the failed system before failure, date & time of the failure & anything which might be of importance. 2)Observations should be reported in non-conclusive manner backed up with photos. 3)Hypotheses of the failure mode based on interpretations from the observations to be included 4)Conclusion - Most likely failure mode out of all hypotheses. 5)Recommendations,if required.

Writing the report in an easy to understand way is absolutely critical. Usually the person closest to the analysis is so familiar with the material that conclusions may even seem obvious to them so I've had great success asking an uninvolved, non-technical colleague to review information. Always err on the side of assuming your audience doesn't know much about the theories, equipment, or practice. Pictures and information added with SNAGIT software is super helpful. Write a highlight summary and then include pages and pictures of extensive details in an appendix to not "bore" people with details if they trust you!

What this "AI" facilitated article totally missed, and is covered in detailed depth in my new book, is 1) to turn on your brain / mind and 2) learn how to practice turning on and optimizing your visual interpretation and thinking skills. Of course "AI" can't do any of those things. Want to leave the hard "thinking" to a machine? Then follow this advice as given. Want to keep this experiment we call humanity going? Read my book. The actual FA procedure embedded in the book (Chapter 6) is called The Step Zero Method. Get the book. Read it. Practice the exercises. You will experience your expertise grow sooner!