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The Development of Two Composite Energy Absorbers for Use in a Transport Rotorcraft Airframe Crash Testbed (TRACT 2) Full-Scale Crash TestTwo composite energy absorbers were developed and evaluated at NASA Langley Research Center through multi-level testing and simulation performed under the Transport Rotorcraft Airframe Crash Testbed (TRACT) research program. A conical-shaped energy absorber, designated the conusoid, was evaluated that consisted of four layers of hybrid carbon-Kevlar plain weave fabric oriented at [+45deg/-45deg/-45deg/+45deg] with respect to the vertical direction. A sinusoidal-shaped energy absorber, designated the sinusoid, was developed that consisted of hybrid carbon-Kevlar plain weave fabric face sheets, two layers for each face sheet oriented at +/-45deg with respect to the vertical direction, and a closed-cell ELFOAM P200 polyisocyanurate (2.0-lb/cu ft) foam core. The design goal for the energy absorbers was to achieve average floor-level accelerations of between 25- and 40-g during the full-scale crash test of a retrofitted CH-46E helicopter airframe, designated TRACT 2. Variations in both designs were assessed through dynamic crush testing of component specimens. Once the designs were finalized, subfloor beams of each configuration were fabricated and retrofitted into a barrel section of a CH-46E helicopter. A vertical drop test of the barrel section was conducted onto concrete to evaluate the performance of the energy absorbers prior to retrofit into TRACT 2. The retrofitted airframe was crash tested under combined forward and vertical velocity conditions onto soft soil. Finite element models were developed of all test articles and simulations were performed using LS-DYNA, a commercial nonlinear explicit transient dynamic finite element code. Test-analysis results are presented for each energy absorber as comparisons of time-history responses, as well as predicted and experimental structural deformations and progressive damage under impact loading for each evaluation level.
Document ID
Acquisition Source
Langley Research Center
Document Type
Conference Paper
Littell, Justin D.
(NASA Langley Research Center Hampton, VA, United States)
Jackson, Karen E.
(NASA Langley Research Center Hampton, VA, United States)
Annett, Martin S.
(NASA Langley Research Center Hampton, VA, United States)
Seal, Michael D.
(Analytical Mechanics Associates, Inc. Hampton, VA, United States)
Fasanella, Edwin L.
(National Inst. of Aerospace Hampton, VA, United States)
Date Acquired
May 9, 2016
Publication Date
May 5, 2015
Subject Category
Aircraft Design, Testing And Performance
Report/Patent Number
Meeting Information
Meeting: AHS International Annual Forum and Technology Display
Location: Virginia Beach, VA
Country: United States
Start Date: May 5, 2015
End Date: May 7, 2015
Sponsors: American Helicopter Society, Inc.
Funding Number(s)
WBS: WBS 664817.
Distribution Limits
Public Use Permitted.
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