Dynamic and Quasi-Static Grade Crossing Collision Tests

Abstract

To support the development of a proposed rule [1], a fullscale dynamic test and two full-scale quasi-static tests have been performed on the posts of a state-of-the-art (SOA) end frame. These tests were designed to evaluate the dynamic and quasi-static methods for demonstrating energy absorption of the collision and corner posts. The tests focused on the collision and corner posts individually because of their critical positions in protecting the operator and passengers in a collision where only the superstructure, not the underframe, is loaded. There are many examples of collisions where only the superstructure is loaded.For the dynamic test, a 14,000-lb cart impacted a standing cab car at a speed of 18.7 mph. The cart had a rigid striking surface in the shape of a coil mounted on the leading end that concentrated the impact load on the collision post. During the dynamic test the collision post deformed approximately 7.5 inches, and absorbed approximately 137,000 ft-lbs of energy. The SOA collision post was successful in preserving space for the operators and the passengers.For the quasi-static test of the collision post, the collision post was loaded in the same location and with the same fixture as the dynamic test. The post absorbed approximately 110,000 ft-lb of energy in 10 inches of permanent, longitudinal deformation. For the quasi-static test of the corner post, the post was loaded at the same height as the collision post, with the same fixture. The corner post absorbed 136,000 ft-lb of energy in 10 inches of permanent, longitudinal deformation.The series of tests was designed to compare the dynamic and quasi-static methods for measuring collision energy absorption during structural deformation as a measure of crashworthiness. When properly implemented, either a dynamic or quasi-static test can demonstrate the crashworthiness of an end frame. INTRODUCTIONThree tests were designed to demonstrate test methods and to measure the crashworthiness of the Federal Railroad Administration (FRA) prototype end frame design. The prototype design, referred to as the state-of-the-art (SOA) design, has enhanced loading capabilities. A proposed rule allows for either quasi-static or dynamic evaluation scenarios for the two major end frame components: the collision and corner posts. By requiring energy absorption capabilities for new end frames, the rule aims to improve survivability for operators and passengers at higher collision speeds. This paper covers work done to support a proposed rule: a dynamic test of a collision post, a quasi-static test of a collision post, and a quasi-static test of a corner post. The work is used both to support the development of the rule and to assist the government and industry in building and evaluating structures built to the standards of the proposed rule.

Fuel Tank Integrity Research: Fuel Tank Analyses and Test Plans

“…These two indenters are currently mounted to a modified railcar, which was used as a ram car in a set of tank car impact tests conducted at TTC [7,8]. A second possible impact vehicle for the fuel tank testing program is a cart that was used for a set of end frame impact tests, also conducted at TTC [5]. The ram cart from the endframe test is shown in Figure 23.…”

“…The 14-kip mass is the mass of a test cart that was used in dynamic tests of passenger car end frame structures [5] conducted to support the development of 49CFR238 Appendix F [3]. The 100-kip mass is the approximate mass of a passenger car.…”

Results of a Diesel Multiple Unit Fuel Tank Blunt Impact Test

“…The deformable cart was adapted from a model originally assembled for a previous impact testing program [6]. The pre-test FE model also featured deformable rubber bushings and bolts to represent the mounting of the tank to the C-channels.…”

Conventional Fuel Tank Blunt Impact Tests: Test and Analysis Results

“…A model of a deformable cart was incorporated into post-test models to evaluate the effect of lumping the cart mass into a rigid impactor versus distributing the mass through the cart and allowing the cart to deform in response to the impact. This model was based upon FE models of this cart developed during a previous research program [5].…”