Forensic engineering has been defined as "the investigation of failures—ranging from serviceability to catastrophic—which may lead to legal activity, including both civil and criminal"."Editor's preface." i–ii. In:
It includes the investigation of material science, products, or components that fail or do not operate or function as intended, causing personal injury, damage to property or economic loss. The consequences of failure may give rise to action under either criminal or civil law including but not limited to health and safety legislation, the laws of contract and/or product liability and the laws of tort. The field also deals with retracing processes and procedures leading to accidents in operation of vehicles or machinery. Generally, the purpose of a Forensics engineering investigation is to locate cause or causes of failure with a view to improve performance or life of a component, or to assist a court in determining the facts of an accident. It can also involve investigation of intellectual property claims, especially . In the US, forensic engineers require a professional engineering license from each state.
History
Investigation
When investigating a case a forensic engineer will follow a series of standard steps of their investigation process. First thing is when the forensic engineer arrives to the scene is to establish safety, they make sure that all the hazards have been dealt with an are safe to handle and be analyzed. The next step would be to do an initial incident appraisal, this is done before any analysis is done and they take a quick observation of what the solution is at hand. The third step in the investigative process is to plan how to the investigation will go and would resources they will need to obtain to do the analysis accurately. Next would be establishing the terms of reverence, this is when the forensic engineer will consult with the client on what they want done in the investigation. The next step is to create the investigative team, once there is plan on how to investigate they will make a team of the experts in the given field needed to conduct the analysis. lastly would be to start the investigation, and this is where they conduct their analysis.
Analysis
Failure mode and effects analysis (FMEA) and fault tree analysis methods also examine product or process failure in a structured and systematic way, in the general context of safety engineering. However, all such techniques rely on accurate reporting of and precise ID, of the failure modes involved.
There is some common ground between forensic science and forensic engineering, such as scene of crime and scene of accident analysis, integrity of the evidence, and court appearances. Both disciplines make extensive use of optical and scanning electron microscopes, for example. They also share common use of spectroscopy (infrared, ultraviolet, and nuclear magnetic resonance) to examine critical evidence. Radiography using (such as X-ray computed tomography), or is also very useful in examining thick products for their internal defects before destructive examination is attempted. Often, however, a simple Magnifying glass may reveal the cause of a particular problem.
Trace evidence is sometimes an important factor in reconstructing the sequence of events in an accident. For example, tire burn marks on a road surface can enable vehicle speeds to be estimated, when the brakes were applied and so on. Ladder feet often leave a trace of movement of the ladder during a slip and may show how the accident occurred. When a product fails for no obvious reason, SEM and Energy-dispersive X-ray spectroscopy (EDX) performed in the microscope can reveal the presence of aggressive chemicals that have left traces on the fracture or adjacent surfaces. Thus an acetal resin water pipe joint suddenly failed and caused substantial damages to a building in which it was situated. Analysis of the joint showed traces of chlorine, indicating a stress corrosion cracking failure mode. The failed fuel pipe junction mentioned above showed traces of sulfur on the fracture surface from the sulfuric acid, which had initiated the crack.
Extracting physical evidence from digital photography is a major technique used in forensic accident reconstruction. Match moving, photogrammetry, and photo rectification techniques are used to create three-dimensional and top-down views from the two-dimensional photos typically taken at an accident scene. Overlooked or undocumented evidence for accident reconstruction can be retrieved and quantified as long as photographs of such evidence are available. By using photographs of the accident scene including the vehicle, "lost" evidence can be recovered and accurately determined.
Forensic materials engineering involves methods applied to specific materials, such as , , , composites and .
Organizations
Examples
The nylon 6,6 had been attacked by the following reaction, which was catalyzed by the acid:
Diesel fuel is especially hazardous on road surfaces because it forms a thin, oily film that cannot be easily seen by drivers. It is much like black ice in its slipperiness, so skids are common when diesel leaks occur. The insurers of the van driver admitted liability and the injured driver was compensated.
Applications
Failures that occur early in the life of a new product are vital information for the manufacturer to improve the product. New product development aims to eliminate defects by testing in the factory before launch, but some may occur during its early life. Testing products to simulate their behavior in the external environment is a difficult skill, and may involve accelerated life testing for example. The worst kind of defect to occur after launch is a safety-critical defect, a defect that can endanger life or limb. Their discovery usually leads to a product recall or even complete withdrawal of the product from the market. Product defects often follow the bathtub curve, with high initial failures, a lower rate during regular life, followed by another rise due to wear-out. National standards, such as those of ASTM and the BSI Group, and International Standards can help the designer in increasing product integrity.
Historic examples
Although strong in compression, cast iron was known to be brittle in tension or bending. On the day of the accident, the bridge deck was covered with track ballast to prevent the oak beams supporting the track from catching fire, imposing a heavy extra load on the girders supporting the bridge and probably exacerbating the accident. Stephenson took this precaution because of a recent fire on the Great Western Railway at Uxbridge, London, where Isambard Kingdom Brunel's bridge caught fire and collapsed.
One of the first major inquiries conducted by the newly formed Railway Inspectorate was conducted by Captain Simmons of the Royal Engineers, and his report suggested that repeated flexing of the girder weakened it substantially. He examined the broken parts of the main girder, and confirmed that the girder had broken in two places, the first break occurring at the center. He tested the remaining girders by driving a locomotive across them, and found that they deflected by several inches under the moving load. He concluded that the design was flawed, and that the wrought iron trusses fixed to the girders did not reinforce the girders at all, which was a conclusion also reached by the jury at the inquest. Stephenson's design had depended on the wrought iron trusses to strengthen the final structures, but they were anchored on the cast iron girders themselves, and so deformed with any load on the bridge. Others (especially Stephenson) argued that the train had derailed and hit the girder, the impact force causing it to fracture. However, Witness said that they saw the girder break first, and that the locomotive and tender were still on the track at the far side of the bridge.
Publications
The journal Engineering Failure Analysis (), published in affiliation with the European Structural Integrity Society, publishes case studies of a wide range of different products, failing under different circumstances.
A publication dealing with failures of buildings, bridges, and other structures, is the Journal of Performance of Constructed Facilities, which is published by the American Society of Civil Engineers, under the umbrella of its Technical Council on Forensic Engineering.
The Journal of the National Academy of Forensic Engineers is a peer-reviewed open access journal that provides a multi-disciplinary examination of the forensic engineering field. Submission is open to NAFE members and the journal's peer review process includes in-person presentation for live feedback prior to a single-blind technical peer review.
See also
- Failure mode and effects analysis
Further reading
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(2026). 9780203484531 ISBN 9780203484531
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(2026). 9780429248016 ISBN 9780429248016
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(2026). 9781003068877 ISBN 9781003068877
- National Academy of Forensic Engineers
- Introduction to Forensic Engineering. OpenLearn. Open University
- Forensic Engineering by Origin and Cause
- Guidelines for Investigating Process Safety Incidents, CCPS, AIChE, Wiley (3rd edition)
- Journals
- Engineering Failure Analysis
- Journal of the National Academy of Forensic Engineers
- Forensic Engineering. Institution of Civil Engineers
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