Development of an Advanced Energy Absorber
Abstract
The attenuation of vertical impact forces in helicopter mishaps is one of the prime factors in determining survivability. Within the cockpit, energy-absorbing crewseats have made significant improvements in helicopter crash survival. The first crashworthy crewseats used fixed-load energy absorbers (EA's) to limit the load on the occupant's spine. These EA's were not adjustable and stroked at a factory-established, constant load through their entire operating range. Energy absorbers (also known as energy attenuators or load limiters) were then developed with a provision for manually adjusting the load so that a wide range of occupants would have equal protection in a crash. An EA load is selected that is proportional to the occupant's weight so that each occupant will experience similar acceleration and use similar stroking space in a crash. This technology was applied in programs to retrofit new seats into the U.S. Navy's CH-53 Sea Stallion and SH-3 Sea King aircraft. Work is currently underway to produce the next-generation energy absorber. The improved EA must be able to perform several functions. It must exhibit a load-deflection curve that produces the most efficient operation within the limits of human tolerance and within the limited vertical space available in military helicopters. It must also provide equal protection for the entire aircrew population, from the smallest female to the largest male. The efforts to date have produced very promising results. This paper summarizes the development of the advanced energy absorber stroking profile and the seat dynamic test results.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 21, 1999
- Accession Number
- ADA375734
Entities
People
- Marvin K. Richards
- Roger Podob
Organizations
- Naval Air Warfare Center