by Michael Hill, Ph.D., P.E. | Biomechanics
Biomechanical engineers investigate a wide variety of cases involving injuries and injury claims, including workplace accidents, falling objects, product failures, slip, trip, and falls, in addition to motor vehicle accidents. Whereas civil engineers, industrial and safety experts, premises liability experts, and accident reconstructionists perform inspections to check for compliance with various codes and may investigate the physics of an incident and what may have gone wrong to cause it, biomechanical engineers analyze how the motions and forces involved in an incident resulted in damage to specific body parts.
Biomechanical Engineering Defined
Biomechanical engineering is a part of a larger field of study known as biomedical engineering, which combines the study of living organisms and medicine with the branch of science concerned with devising and creating machines. Biomechanics deals specifically with mechanics, which involves the motions and forces of the machinery. Biomechanical engineers study the mechanical workings of the human body, just as mechanical engineers study the mechanical workings of materials used in designing automobiles, airplanes, assembly lines, etc.
Biomechanics in Industrial Settings
There are a variety of situations at the workplace that result in injuries, which may be reported. These may involve potential trip hazards, interacting with different types of machinery, performing routine tasks, or accidents involving motorized vehicles such as automobiles, forklifts, yard mules, etc. Below are descriptions of a few case studies based on real-world accidents in which a biomechanical engineer was able to assist.
Forklift and Trailer Pinch Point
An employee at a warehouse was nearing the end of his early-morning shift. After a trailer had been unloaded at the dock, the employee was tasked with closing the trailer door. The employee was not able to reach a strap to close the door, so he used a forklift to assist. He reversed the forklift down a ramp to the trailer door, reached up and out of the forklift to grab the strap, moved the forklift forward up the ramp, and then stepped off the forklift to close the door. As he was lowering the trailer door to close it, the forklift moved back down the ramp and pinned the employee against the door. A security camera recorded the incident.
A forensic biomechanical engineer was retained to investigate the case. As part of the investigation, the engineer inspected and 3D-scanned the forklift, the strap, and the site where the incident occurred. By applying the peer-reviewed literature on human size and reach, the biomechanical engineer worked with animators to reconstruct the incident, showing how the employee moved based on his size, the geometry of the site, and on the surveillance footage. The conclusion was that the employee exited the forklift while it was still in motion, resulting in the accident.
Falling Object on a Hard Hat
At an industrial site, an employee was working on a level below another employee, when the former dropped his hard hat onto the hard hat of the latter standing below. A forensic biomechanical engineer was retained and performed testing and literature research to determine the forces and head accelerations that were involved. The engineer concluded that the components of the hard hat, including the suspension and hard outer shell, served their purpose in reducing the head accelerations compared to a no-hard-hat scenario. The biomechanical engineer opined that the resulting accelerations would not be consistent with the reported brain injuries.
Operating a Lift on an Asphalt Surface
A city parks service employee was driving a telescopic forklift along a city-maintained asphalt road between sites. The employee reported that he sustained spinal injuries due to the vibrations induced while driving over rough portions of the road. The forklift and a driver were instrumented with accelerometers and high-speed video cameras, and the forklift was driven along the reported route. Also, the driver’s head and upper torso were recorded by standard and high-speed video equipment from a vehicle following behind. The accelerations were determined to be well within those experienced during typical driving situations. The head and upper body movement were very minimal and definitely within the movements expected during routine activities of daily living. The biomechanical engineer concluded that biomechanical mechanisms for spinal injuries were not present during the reported incident.
Trip and Fall in a Parking Lot
In the parking lot of a chain grocery store in a busy city center, a customer tripped and fell as she exited the grocery store and walked across the parking lot. The customer claimed that the grocery store had poorly maintained the parking lot and that it presented an unreasonably dangerous condition. Low-resolution surveillance video of the accident depicted the trip and fall, but it was not clear precisely in which area the fall occurred. The site was inspected, and a higher-resolution video camera was elevated on a boom to be adjacent to the subject surveillance camera. The high-resolution footage of people walking to and from the parking lot and grocery store was compared to the low-resolution video from the subject surveillance camera to determine the precise location of the fall. It was determined that a car was turning into the parking lot, so the plaintiff increased her speed and fell into an area in which there were no parking stops or potential tripping hazards. A biomechanical engineer concluded that there were no exceptionally dangerous tripping hazards in the area.
Summary
Biomechanical engineers play a crucial role in a range of impactful tasks, including conducting sophisticated forensic analyses for personal injury litigation and pioneering the design of biomedical devices and methodologies that address injuries and diseases. By meticulously examining accident scenarios, forensic biomechanical engineers can identify critical hazards and evaluate whether the reported injuries are consistent with, or logically arise from, the mechanics of the incident. Their work not only enhances our understanding of accidents but also significantly contributes to the advancement of safety standards and injury prevention strategies.
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Michael Hill, Ph.D., P.E., is a Biomechanical Engineer at Quality Forensic Engineering, LLC. His background is in orthopedic and cardiovascular biomechanics, vehicle accident reconstruction, injury consistency analysis, mechanical design, instrumentation, and experimental analysis. Dr. Hill has lectured at universities and his research findings have been published in 17 academic articles. Dr. Hill has presented at over 40 international and national scientific conferences and his work has been extensively cited by others. His primary focus is on motor vehicle accidents and premises liability incidents, for both plaintiff and defense cases.
