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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1983

Crash tests of three identical low-wing single-engine airplane

Three identical four place, low wing single engine airplane specimens with nominal masses of 1043 kg were crash tested under controlled free flight conditions. The tests were conducted at the same nominal velocity of 25 m/sec along the flight path. Two airplanes were crashed on a concrete surface (at 10 and 30 deg pitch angles), and one was crashed on soil (at a -30 deg pitch angle). The three tests revealed that the specimen in the -30 deg test on soil sustained massive structural damage in the engine compartment and fire wall. Also, the highest longitudinal cabin floor accelerations occurred in this test. Severe damage, but of lesser magnitude, occurred in the -30 deg test on concrete. The highest normal cabin floor accelerations occurred in this test. The least structural damage and lowest accelerations occurred in the 10 deg test on concrete.

Castle, C. B.↗
NASA NTRS1993

Instrumentation and data acquisition for full-scale aircraft crash testing

The Landing and Impact Dynamics Branch of the NASA Langley Research Center has been conducting full-scale aircraft crash tests since the 1970s. Using a pendulum method, aircraft are suspended by cables from a 240-ft high gantry and swung into the impact surface at various attitudes and velocities. Instrumentation for these tests include on-board high-speed cameras, strain gages, load cells, displacement transducers, and accelerometers. Transducers in the aircraft are hard-wired through a long umbilical cable to the data acquisition room. Up to 96 channels of data can be collected at a typical rate of 4000 samples per second. Data acquisition using an FM multiplexed analog system and a high-speed personal computer based digital system is described.

Jones, Lisa E.↗
NASA NTRSDate not supplied

An Overview of the NASA Lift+Cruise eVTOL Crash Test

Introduction – NASA RVLT Project Impact Dynamics / Crash Safety Task - Task Objective: “To improve the crashworthiness and impact safety of Urban Air Mobility (UAM) vehicle and provide data to simplify the certification process. Efforts will include development of validated computational models of these vehicles, as well as other impacting bodies such as birds and drones. Efforts will also focus on developing and evaluating energy absorbing and crush properties of emerging and non-traditional composite materials and processes. Finally, occupant protection will be addressed using computational models and physical assets as it pertains to all rotorcraft environments.” - Problem Statement: “There currently is a lack of data for requirements regarding the crashworthy performance of UAM vehicles and impact loads generated by a bird strike. To address this technology gap, NASA will develop test guidelines, adopt modeling methodologies demonstrating capability for ‘certification by analysis’, acquire vehicle and occupant data on full-scale representative vehicles, and provide data/guidance to consensus standards organizations and the UAM community.” - 4 Main focus points - The investigation of occupant injury using physical and computational assets - The development of energy absorbing technology - The generation of data from sub- and full-scale crash test data - The execution of advanced finite element modelling techniques

evtol↗
NASA NTRS2008

The Use of a Vehicle Acceleration Exposure Limit Model and a Finite Element Crash Test Dummy Model to Evaluate the Risk of Injuries During Orion Crew Module Landings

A review of astronaut whole body impact tolerance is discussed for land or water landings of the next generation manned space capsule named Orion. LS-DYNA simulations of Orion capsule landings are performed to produce a low, moderate, and high probability of injury. The paper evaluates finite element (FE) seat and occupant simulations for assessing injury risk for the Orion crew and compares these simulations to whole body injury models commonly referred to as the Brinkley criteria. The FE seat and crash dummy models allow for varying the occupant restraint systems, cushion materials, side constraints, flailing of limbs, and detailed seat/occupant interactions to minimize landing injuries to the crew. The FE crash test dummies used in conjunction with the Brinkley criteria provides a useful set of tools for predicting potential crew injuries during vehicle landings.

Lawrence, Charles↗
NASA NTRS1981

Evaluation of Emergency-Locator-Transmitter performance in real and simulated crash tests

Emergency locator transmitter (ELT) activation problems were investigated by testing a sampling of ELT units in actual crashes and in a special test apparatus which simulated longitudinal crash pulses with superimposed local structural resonances. The probable causes of excessive false alarms and nonactivation of ELT's during crash situations were determined. Solutions to operational and technical problems were also examined as well as the sensitivity of ELT impact switches to orientation and to local structural vibrations.

Carden, H. D.↗
NASA NTRS1981

Evaluation of emergency-locator-transmitter performance in real and simulated crash tests

Emergency locator transmitter (ELT) activation problems were investigated by testing a sampling of ELT units in actual airplane crashes and in a special test apparatus which simulated longitudinal crash pulses with superimposed local structural resonances. Probable causes of excessive false alarms and nonactivations of ELT's during crash situations were determined and solutions to the current operational and technical problems were obtained. The results, which considered placement, mounting, and activation of ELT's under simulated crash impacts, and an evaluation of the sensitivity of ELT impact switches to orientation and to local structural vibrations are discussed.

Carden, H. D.↗
NASA NTRS2004

Crash Testing of Helicopter Airframe Fittings

As part of the Rotary Wing Structures Technology Demonstration (RWSTD) program, a surrogate RAH-66 seat attachment fitting was dynamically tested to assess its response to transient, crash impact loads. The dynamic response of this composite material fitting was compared to the performance of an identical fitting subjected to quasi-static loads of similar magnitude. Static and dynamic tests were conducted of both smaller bench level and larger full-scale test articles. At the bench level, the seat fitting was supported in a steel fixture, and in the full-scale tests, the fitting was integrated into a surrogate RAH-66 forward fuselage. Based upon the lessons learned, an improved method to design, analyze, and test similar composite material fittings is proposed.

Clarke, Charles W.↗
NASA NTRS1976

Crash test of a liquid hydrogen automobile

Details of the conversion of a U.S. Postal Service mail truck to hydrogen-fueled operation are given. Specific reference is made to design safety considerations. A traffic accident is described that caused the mail truck (mounted on a trailer) to turn on its side at approximately 20 mph and to finally slide to a stop and turn upside down. No one was injured, and there was essentially no damage to the liquid hydrogen fuel system. The mail truck was driven away from the scene of the accident. Suggestions to insure the safety of hydrogen-fueled experimental vehicles are made.

Finegold, J. G.↗
NASA NTRS1993

Development and use of computational techniques in Army Aviation research and development programs for crash resistant helicopter technology

During the 1960's over 30 full-scale aircraft crash tests were conducted by the Flight Safety Foundation under contract to the Aviation Applied Technology Directorate (AATD) of the U.S. Army Aviation Systems Command (AVSCOM). The purpose of these tests were to conduct crash injury investigations that would provide a basis for the formulation of sound crash resistance design criteria for light fixed-wing and rotary wing aircraft. This resulted in the Crash Survival Design Criteria Designer's Guide which was first published in 1967 and has been revised numerous times, the last being in 1989. Full-scale aircraft crash testing is an expensive way to investigate structural deformations of occupied spaces and to determine the decelerative loadings experienced by occupants in a crash. This gave initial impetus to the U.S. Army to develop analytical methods to predict the dynamic response of aircraft structures in a crash. It was believed that such analytical tools could be very useful in the preliminary design stage of a new helicopter system which is required to demonstrate a level of crash resistance and had to be more cost effective than full-scale crash tests or numerous component design support tests. From an economic point of view, it is more efficient to optimize for the incorporation of crash resistance features early in the design stage. However, during preliminary design it is doubtful if sufficient design details, which influence the exact plastic deformation shape of structural elements, will be available. The availability of simple procedures to predict energy absorption and load-deformation characteristics will allow the designer to initiate valuable cost, weight, and geometry tradeoff studies. The development of these procedures will require some testing of typical specimens. This testing should, as a minimum, verify the validity of proposed procedures for providing pertinent nonlinear load-deformation data. It was hoped that through the use of these analytical models, the designer could optimize aircraft design for crash resistance from both a weight and cost increment standpoint, thus enhancing the acceptance of the design criteria for crash resistance.

Burrows, Leroy T.↗
NASA NTRS2012

Development and Calibration of a System-Integrated Rotorcraft Finite Element Model for Impact Scenarios

Two full-scale crash tests of an MD-500 helicopter were conducted in 2009 and 2010 at NASA Langley's Landing and Impact Research Facility in support of NASA s Subsonic Rotary Wing Crashworthiness Project. The first crash test was conducted to evaluate the performance of an externally mounted composite deployable energy absorber (DEA) under combined impact conditions. In the second crash test, the energy absorber was removed to establish baseline loads that are regarded as severe but survivable. The presence of this energy absorbing device reduced the peak impact acceleration levels by a factor of three. Accelerations and kinematic data collected from the crash tests were compared to a system-integrated finite element model of the test article developed in parallel with the test program. In preparation for the full-scale crash test, a series of sub-scale and MD-500 mass simulator tests were conducted to evaluate the impact performances of various components and subsystems, including new crush tubes and the DEA blocks. Parameters defined for the system-integrated finite element model were determined from these tests. Results from 19 accelerometers placed throughout the airframe were compared to finite element model responses. The model developed for the purposes of predicting acceleration responses from the first crash test was inadequate when evaluating more severe conditions seen in the second crash test. A newly developed model calibration approach that includes uncertainty estimation, parameter sensitivity, impact shape orthogonality, and numerical optimization was used to calibrate model results for the full-scale crash test without the DEA. This combination of heuristic and quantitative methods identified modeling deficiencies, evaluated parameter importance, and proposed required model changes. The multidimensional calibration techniques presented here are particularly effective in identifying model adequacy. Acceleration results for the calibrated model were compared to test results and the original model results. There was a noticeable improvement in the pilot and copilot region, a slight improvement in the occupant model response, and an over-stiffening effect in the passenger region. One lesson learned was that this approach should be adopted early on, in combination with the building-block approaches that are customarily used, for model development and pretest predictions. Complete crash simulations with validated finite element models can be used to satisfy crash certification requirements, potentially reducing overall development costs.

Annett, Martin S.↗
NASA NTRSDate not supplied

Test and Simulation of a Fokker F28 Crash Landing

Test and Simulation of a Fokker F28 Crash Landing – Jacob B. Putnam 1, Justin D. Littell 1, Karen E. Jackson 2; 1 NASA Langley Research Center, Hampton, VA, 2 National Institute of Aerospace, Hampton, VA. In June of 2019, the National Aeronautics and Space Administration (NASA) Langley Research Center (LaRC) conducted a full-scale crash test of a Fokker F28 MK1000 aircraft. Aircraft crash-worthiness is typically evaluated through component level tests (i.e. vertical drops of fuselage subsections or isolated seat tests). Finite Element Models (FEMs) are also used to bridge the gap between component testing and full-scale crash prediction. The full-scale crash test performed in conjunction with previous subsection testing of a Fokker F28 fuselage provided the opportunity to evaluate differences in crash-worthiness predictions between full- and sub-scale testing and to quantify the predictive capability of FEMs in the aerospace crash environment. In this study vehicle crash-worthiness was quantified through anthropometric test devices (ATDs) included in both the full-scale crash test as well as fuselage section drop tests previously performed at NASA LaRC. A FEM of the Fokker F28 aircraft was developed and simulated within the tested environment. Vehicle and ATD response predictions were compared between test and simulation. The International Organization for Standardization ISO/TR 16250 curve comparison methodology was used to provide a quantitative assessment of predictive accuracy for both the vehicle and ATD FEMs. Determination of aircraft crash-worthiness made between the three evaluations methodologies (full-vehicle crash test, component test, and FEM simulation) were then compared. Structural differences as well as the more complex loading environment achieved within the full-vehicle test resulted in increased injury risk compared to that predicted within the component level tests. The FEM simulations were found to produce a more realistic prediction of injury risk within the full-vehicle crash environment than the component level testing. Limitations of both component testing and FEM simulation within aerospace crash environment were identified.

impact testing↗