A detailed design of a sleeved-column energy absorber was developed and fabricated for dynamic testing. The sleeve is a rectangular, hollow, mild steel member with a length of nearly 8 ft. Rectangular structural members are more commonly used in rail vehicle construction than shapes with circular cross sections. A single core element was fabricated from a solid, high-strength, low-alloy steel piece.
Tests indicated that the design crush load is reached at the first stage of crush and then increases by a factor of two for the second stage crush, resulting in a desirable stepped load-crush response distributing energy absorption to other vehicles. Tests were performed and results reviewed by the project panel.