| Popis: |
Investigations of passenger train accidents have revealed serious safety hazards associated with the thin, rigid tops of workstation tables, which are common fixtures aboard rail cars. Thoracic and abdominal injuries caused by occupant impact with workstation tables have been cited as the likely cause of two fatalities during a 2002 accident in Placentia, CA [1]. Additionally, workstation tables have been cited as the cause of injury in reports on accidents in Intercession City, FL [2], and Burbank, CA [3]. Currently there are no regulations or safety standards governing the crashworthiness of tables in passenger trains beyond attachment strength requirements. However, research sponsored by the Federal Railroad Administration (FRA) and in collaboration with the American Public Transportation Association (APTA) Passenger Rail Equipment Safety Standards (PRESS) Construction & Structural working group is underway to develop a mandatory industry safety standard for tables to ensure that they will be designed to provide a minimum level of safety during a train accident. FRA’s Equipment Safety Research Program has already developed and tested a prototype table design to demonstrate the improved occupant protection provided by an energy-absorbing table. The prototype table design was tested using a THOR [4] and an H3RS [5], which are advanced anthropomorphic test devices (ATDs), onboard a 35 mph full-scale train-to-train impact test of rail cars modified to incorporate crash energy management (CEM) [6]. Test results demonstrated that the Injury Assessment Reference Values (IARVs) measured by the instrumented ATDs were within human tolerance levels established by the National Highway Traffic Safety Administration (NHTSA) for automotive crashworthiness for the head, neck, chest, abdomen, and femur. Having demonstrated the effectiveness of an energy-absorbing table, the next step is developing a performance-based safety standard for tables that ensures a minimum level of crashworthiness. The safety standard would employ the use of an 8G dynamic sled test with instrumented ATDs to evaluate occupant injury and structural integrity of the table, similar to the seat test requirements in APTA-SS-C&S-016-99 [7], which is the industry safety standard for passenger seats in rail cars. Normally, advanced ATDs like the THOR would be required to measure abdominal and thoracic loads caused by the table impact during the sled test. However, use of these experimental ATDs for table qualification testing is not feasible due to their limited availability. Therefore, alternative test methods must be developed to evaluate the crashworthiness of workstation tables. This paper evaluates several potential methods to measure table crashworthiness, including quasi-static crush testing, pendulum impact testing, drop tower testing, and sled testing with standard Hybrid III 50th percentile ATDs. The pros and cons of these tests are also described. After evaluating the various testing methods, test conditions for two separate tests are proposed for an industry table standard. A companion paper [8] describes analysis results used to establish performance requirements proposed for evaluating table crashworthiness for the safety standard, in accordance with the test conditions proposed in this paper. |
