The Experts below are selected from a list of 144 Experts worldwide ranked by ideXlab platform
Hamid M Lankarani - One of the best experts on this subject based on the ideXlab platform.
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methods of evaluating es 2 leg flail in dynamic evaluation and certification tests of side facing Aircraft Seats
International Journal of Crashworthiness, 2015Co-Authors: Robert D Huculak, Hamid M LankaraniAbstract:The recent implementation of new federal regulations on injury criteria for occupants in side-facing Seats greatly decreases the risk for these passengers. One of these new requirements limits the amount of leg flail allowed to the occupant. While the limit of rotation is defined at 35°, the method of measurement of this angle is left open to the end user. Photometric analysis and angular rate sensor data are analysed and evaluated, first, on a pendulum fixture to determine any difference between the two and then, second, on an ES-2re anthropomorphic test device (ATD) in a side-facing seat. The leg flail or leg rotation is measured in three different configurations: an unrestrained leg, a rigid block to restrain the leg, and with an airbag deployed to restrain the leg. Various targets are tracked from the high-speed video, and the photometric results for each are compared to the angular rate sensor data during the impact test.
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evaluation of dynamic performance of Aircraft Seats for larger passenger population using finite element analysis
ASME 2012 International Mechanical Engineering Congress and Exposition, 2012Co-Authors: Prasannakumar S Bhonge, Rasoul Moradi, Hamid M LankaraniAbstract:Dynamic Aircraft seat regulations are identified in the Code of Federal Regulations (CFR), 14 CFR Parts § XX.562 for crashworthy evaluation of a seat in dynamic crash environment. The regulations specify full-scale dynamic testing on production Seats. The dynamic tests are designed to demonstrate the structural integrity of the seat to withstand an emergency landing event and occupant safety. These tests are carried out on a 50th percentile Hybrid II Anthropomorphic Test Device (ATD) representing average 50 percent of human population. In this study, the dynamic performance of Seats are evaluated for larger passenger population for both transport and general aviation Seats. For this, Finite Element Analysis (FEA) of an Aircraft seat model is analyzed by utilizing a 50th percentile e-ATD and validated with a 50th percentile ATD sled test results. Then the effect of a 95th percentile standard ATD in an Aircraft passenger seat is investigated using FEA. Comparison of the 50th percentile and the 95th percentile electronic ATD models (e-ATDs) is carried out on the test parameters. This includes the restraint loads, the floor reactions and the head paths. Based on the comparison it is concluded that the seat loads go up in the range of 20 to 30% if designed for larger passenger population.Copyright © 2012 by ASME
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An investigation in crashworthiness evaluation of Aircraft seat cushions at extreme ranges of temperature
Journal of Mechanical Science and Technology, 2010Co-Authors: Hamid Khademhosseini Beheshti, Hamid M LankaraniAbstract:This paper obtains a Mathematical Dynamic Model (MADYMO) for occupant lumbar load evaluation under CFR Part 23 and 25 at extreme ranges of temperature. The validation of results is performed by full scale sled test results. Aircraft industries are using viscoelastic polyurethane foams as seat cushion. Visco-elastic foams bring not only more comfort to the passengers in long term sitting but it also maintains more safety during unpredicted crashes and hard landings. Aircraft seat cushions are exposed to varying temperature ranges during their life time. This fact has motivated Aircraft industries to evaluate the seat cushion dynamic behavior at extreme ranges of temperatures in addition to what is mentioned in Federal Aviation Administration (FAA) Regulations at room temperature. This research provides a methodology based on simulation and modeling to eliminate, or at least, minimize the number of full scale dynamic sled tests defined by regulations for Aircraft Seats at extreme ranges of temperature.
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Computational modeling and performance evaluation of a DAX-foam Aircraft seat cushion utilizing high loading rate dynamic characteristics
Volume 11: New Developments in Simulation Methods and Software for Engineering Applications; Safety Engineering Risk Analysis and Reliability Methods;, 2010Co-Authors: Prasannakumar S Bhonge, Chandrashekhar K. Thorbole, Hamid M LankaraniAbstract:The Aircraft seat dynamic performance standards as per CFR 14 FAR Part 23, and 25 requires the seat to demonstrate crashworthy performance as evaluated using two tests namely Test-I and Test-II conditions. Test-I dynamic test includes a combined vertical and longitudinal dynamic load to demonstrate the compliance of lumbar load requirement for a Hybrid II or an FAA Hybrid III Anthropomorphic Test Device (ATD). The purpose of this test is to evaluate the means by which the lumbar spine of the occupant in an impact landing can be reduced. This test requirement is mandatory with every change in the seat design or the cushion geometry. Experimental full-scale crash testing is expensive and time-consuming event when required to demonstrate the compliance issue. A validated computational technique in contrast provides an opportunity for the cost effective and fast certification process. This study mainly focuses on the characteristics of DAX foams, typically used as Aircraft seat cushions, as obtained both at quasi-static loading rate and at high loading rate. Nonlinear finite element models of the DAX foam are developed based on the experimental test data from laboratory test results conducted at different loading rates. These cushion models are validated against sled test results to demonstrate the validity of the finite element models. The results are compared for these computational sled test simulations with each seat cushion as obtained using quasi-static and high-loading rate characteristics. The result demonstrates a better correlation of the simulation data with the full scale crash test data for the DAX foam when high loading rate data is utilized instead of quasi-static data in the dynamic finite element models. These models can be utilized in the initial design of the Aircraft Seats, and thus reducing the cost and time of a full-scale sled test program.Copyright © 2010 by ASME
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mathematical and hybrid dynamic modeling for sled crash testing on Aircraft Seats
ASM '07 The 16th IASTED International Conference on Applied Simulation and Modelling, 2007Co-Authors: Kh H Beheshti, Hamid M LankaraniAbstract:Occupant lumbar load under CFR Part 23 and 25 is being obtained by using different methodologies including hybrid dynamic modeling and MADYMO analysis. The output of these methods is validated with full scale sled tests results. A crashworthy structure is designed such that in the event of crash, it absorbs impact energy in a controlled manner. The main subsystems of an Aircraft involved in crashworthiness are seat cushion, which is part of seat structure, restraints, fuselage and landing gear. Polyurethane foams are being used as acoustic purposes, as padding in the finished interior panels of the Aircraft, and seat cushions. Their main application is mostly in seating purposes to provide comfort for occupant. All the seat cushions have to pass Federal Aviation Administration (FAA) Regulations before being installed on the Seats. These regulations require a dynamic sled test of the entire seat system for certifying the seat cushions. This traditional dynamic testing is also required for replacing the deteriorated cushions with new buildup cushions which is time consuming and costly. This research provides methodologies based on simulation and modeling to eliminate, or at least, minimize the number of full scale dynamic sled tests defined by regulations for Aircraft Seats.
A De Luca - One of the best experts on this subject based on the ideXlab platform.
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Development of a multibody system for crashworthiness certification of Aircraft seat
Multibody System Dynamics, 2018Co-Authors: Marco Guida, Anna Manzoni, A. Zuppardi, Francesco Marulo, Francesco Caputo, A De LucaAbstract:This work proposes a multibody approach in the simulation of 16-g Aircraft Seats, referred to the front-row of Seats located behind bulkheads compliance with the Head Injury Criteria (HIC) requirement. The multibody model of the seat structure has been developed and analysed by using a home-made algorithm implemented in Matlab® code, as a 2D system of rigid bodies interconnected by springs and joints. The research has been oriented to assess the capability of simulating a 16g frontal impact of a sled equipped with the seat of a regional Aircraft on which an anthropomorphic dummy is arranged. This sled test, for which experimental data were available, has been used as test case; inertial and structural properties of the system have also been experimentally and numerically evaluated in order to make the numerical model compliant with the real one.One of the primary goals of the paper is to provide an intuitive, easily extendable numerical tool to support designers in multibody simulation and to define a tool able to obtain global sled-test results in very short time, especially if compared to the computational time of a detailed finite element simulation. This tool will allow running sensitivity analysis and first level optimisation of key design parameters, integrating itself in the design cycle, not in place of, but as a support to the main simulation tools.
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Mixed FE–MB methodology for the evaluation of passive safety performances of aeronautical Seats
International Journal of Crashworthiness, 2018Co-Authors: F. Di Napoli, Francesco Marulo, Francesco Caputo, A De Luca, Michele Guida, Bonaventura VitoloAbstract:ABSTRACTThe certification of Aircraft Seats involves the investigation of the structural performance of their components under emergency landing conditions. . The paper reports the activities relat...
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Development of a multibody system for crashworthiness certification of Aircraft seat
Multibody System Dynamics, 2018Co-Authors: Michele Guida, Anna Manzoni, A. Zuppardi, Francesco Marulo, Francesco Caputo, A De LucaAbstract:This work proposes a multibody approach in the simulation of 16-g Aircraft Seats, referred to the front-row of Seats located behind bulkheads compliance with the Head Injury Criteria (HIC) requirement. The multibody model of the seat structure has been developed and analysed by using a home-made algorithm implemented in Matlab® code, as a 2D system of rigid bodies interconnected by springs and joints. The research has been oriented to assess the capability of simulating a 16g frontal impact of a sled equipped with the seat of a regional Aircraft on which an anthropomorphic dummy is arranged. This sled test, for which experimental data were available, has been used as test case; inertial and structural properties of the system have also been experimentally and numerically evaluated in order to make the numerical model compliant with the real one.
David H. Laananen - One of the best experts on this subject based on the ideXlab platform.
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prediction of head and neck injury in transport Aircraft Seats as a function of occupant size and seat configuration
International Journal of Crashworthiness, 2001Co-Authors: Aarthi Ayyar, David H. LaananenAbstract:Abstract The safety of civil Aircraft Seats is evaluated by dynamic testing using two sets of impact conditions. For transport category Aircraft Seats, the potential for head injury due to impact on seat backs or bulkheads must be determined. The dynamic tests are conducted with a 50th-percentile Hybrid II dummy, and pass/fail criteria include the Head Injury Criterion (HIC). Computer simulations were performed to investigate the variation of HIC and neck loads with dummy size and type and for a range of seat row pitch. Another variable was the break-over resistance of the forward seat back. As expected, predicted values of HIC were higher for larger dummies at a given seat row pitch. Potentially more significant was the result that the HIC values obtained with the 50th-percentile Hybrid III model were generally much higher than those for the Improved Hybrid II under otherwise identical conditions, indicating the need for further investigation. Finally, for many of the cases that were modelled, neck momen...
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CRASHWORTHINESS ANALYSIS OF COMMUTER Aircraft Seats.
1993Co-Authors: David H. LaananenAbstract:Abstract : During the past several years, the Federal Aviation Regulations (FAR) have been significantly modified with respect to seat/restraint system strength, attachment of Seats to the Aircraft structure, and the means by which they are to be evaluated. Aircraft accident data, human tolerance levels, and Aircraft structural characteristics have been considered in the development of these new standards. Dynamic testing is now required for Seats to be installed in general aviation Aircraft, transport category Aircraft, and rotorcraft. Performance criteria are similar to those specified by the Federal Motor Vehicle Safety Standards for automobiles but also include a limit on pelvic force, in order to prevent spinal injuries which may be caused by the vertical component of impact force. A category of Aircraft that has not as yet been affected by the rule modifications is the commuter type Aircraft, which Seats 10 to 19 passengers. Since this airplane is closer in size to general aviation Aircraft than to large transports, it is also covered by FAR Part 23. The Federal Aviation Administration is currently involved in the conduct of a test program addressing commuter Aircraft occupant crash safety. In support of this effort, a research program the includes full-scale Aircraft drop tests, sled tests of Seats, and computer simulations is being conducted. This report describes the use of the SOM-LA (Seat/Occupant Model - Light Aircraft) program in modeling three commuter Aircraft Seats. The predicted response of the Seats to a potential set of test conditions is described. Crashworthiness, Aircraft Seats, Restraint systems, Computer simulation.
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crashworthiness analysis of commuter Aircraft Seats and restraint systems
Journal of Safety Research, 1991Co-Authors: David H. LaananenAbstract:Abstract During the past five years, the U.S. Federal Aviation Regulations (FARs) have been significantly modified with respect to strength of Seats and restraint systems, their attachments to the Aircraft structure, and the means for their evaluation. Aircraft accident data, human tolerance levels, and Aircraft structural characteristics have been considered in developing the new standards, which require dynamic testing of Seats and restraint systems. FAR Part 23, which deals with small airplanes, was first amended to require dynamic testing of Seats and restraint systems for normal and utility (general aviation) Aircraft with capacity for fewer than 10 passengers. Performance criteria are similar to those specified by the U.S. Federal Motor Vehicle Safety Standards for automobiles, but also include a limit on pelvic force in order to prevent spinal injuries that may be caused by the vertical component of impact force. Similar regulatory actions, although requiring somewhat different dynamic test conditions, have also been implemented for transport Aircraft, which are covered by FAR Part 25, and for helicopters, under FAR Parts 27 and 29. Commuter-type Aircraft have not been affected by the FAR modifications. Commuter types seat 10 to 19 passengers, are closer in size to general aviation Aircraft than to large transports, and are also covered by FAR Part 23. The Federal Aviation Administration (FAA) is currently involved in a research program that includes full-scale Aircraft drop tests, sled tests of Seats, and computer simulations that should lead to a proposal for amendment of the regulations for commuter-type Aircraft. The objectives of this paper are to describe the research program and to document some conclusions that may be drawn from its results concerning seat and restraint system design, dynamic testing, and acceptance criteria.
Kazuo Katayama - One of the best experts on this subject based on the ideXlab platform.
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piled up configuration design of decelerators in drop test for Aircraft Seats
International Journal of Impact Engineering, 2014Co-Authors: Masakatsu Chiba, T Okino, Y Nambu, Hiroshi Yutani, Kazuo KatayamaAbstract:Abstract To ensure the safety of Aircraft Seats, it is mandatory to perform a dynamic test under an acceleration pulse prescribed by the Federal Aviation Administration. This paper proposes a design method for a decelerator. The design involves the piling up of paper sandwich panels for use in a drop test. First, a quasi-static compression test of paper core sandwich panels was conducted to examine the displacement–load curve, from which the absorption energy of the panels was deduced. Then, a piled-up configuration of panels was designed via a method based on the rigid, perfectly plastic, locking model proposed by Reid and Peng—in which the dynamic effect of the panel is considered when the core height is constant or variable—under the assumption that the decelerator crushes in descending order starting with the upper panel. Second, a drop tower test was conducted to determine whether the designed decelerator achieves the required acceleration pulse. The results of the proposed method were compared with those of the decelerator design method by Shoji et al. based on the dynamic absorption energy of the panels. The test results indicate that decelerators designed with the proposed method—based on the absorption energy derived from a simple static compression test and employing the effect of dynamic crushing—can produce identical results to those designed with the method by Shoji et al., which is based on the absorbing energy derived from a complicated dynamic compression test.
David M. Moorcroft - One of the best experts on this subject based on the ideXlab platform.
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Neck injury criteria and certification procedure for side-facing Aircraft Seats
2020Co-Authors: M.m.g.m. Philippens, Patrick A. Forbes, Jac Wismans, Richard L. Deweese, David M. MoorcroftAbstract:This report documents research started in 2002 that identified the potential need for explicit neck injury criteria and tolerances for certification of side-facing Seats in Aircraft. Laboratory sled tests with full-body postmortem human subjects proved that there is a substantial risk for serious (potentially lethal) neck injuries under realistic crash load conditions, simulated by the 16-g, 180-ms crash pulse designated by Title 14 Code of Federal Regulations 25.562. Further research of the loading and injury mechanism were conducted using numerical simulations of advanced rigid-body models of the EuroSID-2 (ES-2) anthropomorphic sideimpact crash dummy, which originated from automotive crash safety research. This research led to proposing an ES-2 upperneck tension force injury assessment reference value of 2100 Newton. Injuries to other body structures were documented and recommended for future research as they compromise the escape capabilities of the Aircraft occupants, e.g., unconsciousness by head angular acceleration, immobilization by fractures to the upper leg, multiple rib fractures from belt loading, or carotid artery tears, which can lead to a fatal stroke months after the accident. The ES-2 was determined to have sufficient biofidelity for use in Aircraft side-facing seat certification requirements. Issues with respect to the ES-2’s neck durability and shoulder-belt interaction are noted.
