Journal of the National Academy of Forensic Engineers

FE Evaluation of Hillside Excavation for a Construction Contract Dispute

Rune Storesund — 2020-08-18

This paper presents a forensic evaluation of an earthwork grading dispute between a grading contractor (plaintiff) and property owner (defendant) associated with construction of an approach driveway and hill-side cut for a new residential property. The plaintiff’s allegations were that “changed conditions” had been encountered through the presence of a landslide and/or geologic fault. These conditions resulted in schedule delays and increased costs. Finally, the plaintiff alleged breach of contract after being terminated. The allega-tions were investigated through both on-site field reconnaissance and desktop studies. The forensic analyses found no basis for the changed conditions claims. The case was tried in Napa County California Superior Courts via bench trial. The judge’s decision mirrored the findings of the forensic analyses.

Forensic Engineering Analysis of Common Failures and Inspection Procedures for Residential and Commercial Chairs

Anthony Sasso — 2020-08-18

Chairs have been designed, manufactured, and used by humans for thousands of years. Eventually, all chairs wear out and fail. When someone is injured due to this failure, costly litigation can ensue. Forensic engineers are consulted to investigate the root cause of failure, and whether the mechanism of failure could have been detected prior to the accident to avoid injury. Materials used in chair manufacturing and several examples of failures are discussed in this paper. Industry safety standards and manufacturers’ guidelines are used as a basis for a proposed inspection and maintenance program for chair owners.

Dynamic Motion Simulation: Applications in Forensic Engineering

Mark Webster — 2020-08-18

A worker was injured when a large sculpture overturned while it was being transferred on a wheeled cart from a delivery truck onto a dock lift. This paper introduces the use of dynamic motion simulation (DMS) soft-ware as a forensic engineering tool for analyzing and simulating motion/contact between multiple interacting physical objects. Important inputs to the software include the mass properties of the objects — in this case, a very irregularly shaped sculpture. For simple shapes, the distribution of mass can easily be approximated by manually discretizing the object into several smaller, simpler shapes. Accurate determination of the mass dis-tribution of an irregular shape (such as a sculpture) can be aided by measurement methods such as the laser scanning process used in this case. The resulting scan data was used to create a 3-D computer model that was processed using conventional mechanical computer-aided design (CAD) and DMS software to determine the mass properties and ultimately to simulate the dynamic motion.

Forensic Engineering Investigation into Factors Contributing to Explosion of a Consumer-Grade Tabletop Torch

Jahan Rasty — 2020-08-18

In early 2013, approximately 3,500 consumer-grade tabletop torches, designed for use with citronella oil to ward off insects, were sold by a retailer. Within six months of their debut, 22 of these products experi-enced sudden explosions, resulting in one fatality and 21 severe burn injuries to consumers. The author was retained as an expert in the fatal explosion case to determine the root cause(s) that led to these explosions. This paper will describe the detailed, experimental-based investigation that was carried out to reveal design, manufacturing, and marketing defects for which the designer of the torch, the manufacturer of the fuel, and the retailer of the final product were responsible. It was determined that the explosions occurred as a result of a “perfect storm” scenario that involved defective product design, defective marketing of the product through the sale of incompatible fuel by the retailer, and deficient warning instructions by the manufacturer.

Forensic Engineering Analysis of Upper Extremity Nerve Entrapment Injury Mechanisms as Related to Rear-End Collisions

William Lee — 2020-08-18

Nerve entrapments of the median nerve, i.e., carpal tunnel syndrome (CTS) and the ulnar nerve, i.e., cu-bital syndrome (CT) are relatively common, reflecting traumatic and atraumatic mechanisms. Claims of such injuries in relation to rear-end collisions (particularly low-velocity or < 10 mph collisions) are often contested by the defense, acknowledging that there is no obvious relationship between the collision and the claimed inju-ries. Of the collision types (frontal, side, rear-end), it is the least clear how a rear-end collision can establish mechanisms for such injuries. Direct blunt trauma to the carpal tunnel region or the cubital tunnel region are unlikely in a rear-end collision. Also, “stretch” injuries due to hypermotion of either the wrist or elbow are unlikely, reflecting occupant kinematics, vehicle interior geometry, and other factors. A case study involving CTS and CT claims as a result of a low-velocity rear-end collision will be presented.

Forensic Engineering Investigation of a Furnace Oil Supply Line Fitting Leak

Daniel P Couture — 2020-08-18

A basement oil leak was reported to a service company, which immediately replaced a supply line SAE 37° fitting body while leaving the flared copper lines in place. An environmental remediation claim was later made against this service company, alleging improper installation of new supply lines within the prior year. Fuel delivery records and heating degree day records were analyzed, revealing a consumption rate discrep-ancy versus the homeowner’s narrative. An experimental apparatus was designed to evaluate leak rates for flared fittings in tightened and partially loosened states. The modeled expected consumption rate results inferred tampering with the fittings several days prior to the leak report. The experimental technique and consumption rate analysis withstood a Daubert challenge for relevance at the mediation conference.

Forensic Engineering Analysis of the Alleged Failure of an Emergency Vehicle Traffic Light Preemption System

Robert Peruzzi — 2020-08-18

This case involved a fatal collision between a police vehicle (operated by a police officer) and a non-police vehicle (operated by a civilian). With lights and sirens activated, the officer in pursuit ran a red light and crashed into the civilian’s vehicle in an intersection whose traffic light controller included an emergency vehicle preemption system. The civilian driver was mortally injured, and died the next day. The estate of the deceased driver sued the police officer, municipal police department, and manufacturer of the emergency vehicle preemption system. The author was retained by counsel for the estate of the deceased to assist in the case against the manufacturer of the emergency vehicle preemption system and municipality. The evidence showed that the preemption system was working properly, but that the system’s confirmation lights had been improperly programmed. A maximum speed was calculated at which a preempted green light for emergency drivers would be assured. Event logs in the police vehicle showed that the police officer was driving too fast for the traffic light controller to cycle through its sequence before the officer reached the intersection.