scholarly journals Development of a Head Injury Criteria-Compliant Aircraft Seat by Design of Experiments

Aerospace ◽  
2019 ◽  
Vol 6 (9) ◽  
pp. 95
Author(s):  
Giuseppe Lamanna ◽  
Amalia Vanacore ◽  
Michele Guida ◽  
Francesco Caputo ◽  
Francesco Marulo ◽  
...  
Keyword(s):  
Head Injury ◽  
Seat Belt ◽  
Numerical Procedure ◽  
Design Solution ◽  
Fe Model ◽  
Accurate Analysis ◽  
Sled Test ◽  
Passenger Seat ◽  
Head Injury Criteria ◽  
The Impact

This paper deals with the redesign of an aircraft passenger seat, placed at the first seat row, which was not compliant with Federal Aviation Regulations FAR 25.562 “Emergency landing dynamic conditions” regulation (due to a high value for the Head Injury Criterion (HIC)) and related guidelines. Starting from an accurate analysis of some results obtained via an experimental seat sled test, a numerical procedure was developed in order to improve the passenger safety with respect to head injury. Specifically, the proposed numerical procedure, using the advantages of a Finite Element (FE) model and a Design of Experiment (DoE) approach for simulation modeling, was aimed at identifying a new design solution to avoid the impact between the passenger’s head and the bulkhead. The redesign of the passenger seat was validated against an experimental test carried out at Geven S.p.A. Company by demonstrating, consequently, the compliance of the modified seat-belt system with the regulations.

Design and Validation of a Component Head Injury Criteria Tester for Aerospace Applications

2005 ◽  
Author(s):  
Hamid M. Lankarani ◽  
C. S. Koshy ◽  
C. K. Thorbole
Keyword(s):  
Head Injury ◽  
Seat Belt ◽  
Impact Angle ◽  
Head Impact ◽  
Aircraft Cabins ◽  
Aerospace Applications ◽  
Injury Criteria ◽  
Test Conditions ◽  
Head Injury Criteria ◽  
Impact Events

The compliance with Head Injury Criteria (HIC) specified in 14 CFR 23.562 [1] and CFR 25.562 [2] poses a significant problem for many segments of the aerospace industry. The airlines and the manufacturers of jet transports have made claims of high costs and significant schedule overruns during the development and certification of 16G seats because of the difficulties encountered in meeting this requirement. The current practice is to conduct Full Scale Sled Tests (FSST) on impact sleds. This approach can be expensive, since a new seat may be needed for each test. Moreover, some consider the HIC sensitive to changes in the test conditions, such as sled pulse, seat belt elongation, etc., resulting in HIC results from FSSTs showing poor repeatability. These difficulties make it desirable to devise a cheaper, faster, and more repeatable alternative to FSSTs. This paper describes an attempt to address these issues by designing a device, the National Institute for Aviation Research (NIAR) HIC Component Tester (NHCT) using various multibody tools. This device was then fabricated and its performance evaluated against FSSTs conducted under similar test conditions for some typical impact events that occur in an aircraft cabins e.g. impact with bulkheads. The factors compared for this evaluation are the head impact angle, head impact velocity, HIC, HIC window, peak head C.G. resultant acceleration, average head C.G. resultant acceleration, and head C.G. resultant acceleration profiles. The results of these evaluations show that the NHCT already produces test results that correlate significantly with FSST results for impact targets such as bulkheads and its target envelope is expected eventually to include objects such as seat backs.

Responses of Hybrid-III 50th and Thor-NT 50th in Sled Tests With Different Seat Belt Pretensioner Configurations

2006 ◽  
Author(s):  
Chang In Paek ◽  
Greg Shaw ◽  
Jeff Crandall ◽  
Yoon Ho Baek ◽  
Ol Suk Ko
Keyword(s):  
Head Injury ◽  
Seat Belt ◽  
Relative Sensitivity ◽  
Forward Movement ◽  
Similar Test ◽  
Injury Criteria ◽  
Hybrid Iii ◽  
Head Injury Criteria ◽  
Test Repeatability

This study quantifies the effectiveness of the various seat belt pretensioner configurations relative to the no pretensioner condition and defines the relative sensitivity of the Hybrid-III 50th and THOR-NT 50th percentile male anthropomorphic test devices to pretensioner effects. The results of this study indicate that pretensioners reduced the chest accelerations and Head Injury Criteria (HIC) of both Hybrid-III and THOR-NT dummies. In addition, the pretensioners reduced the chest forward movement by providing restraint earlier in the event. The dual pretensioners and the retractor pretensioners were more effective than the buckle pretensioner and the no pretensioner conditions. Although the Hybrid-III and THOR-NT were different in construction and sitting depth, the Hybrid-III and THOR-NT's responses to the pretensioner conditions were similar. Test-to-test repeatability was acceptable for both dummies.

Prediction of impact response in construction safety helmet using FEA

2019 ◽  
Vol 18 (3) ◽  
pp. 557-566
Author(s):  
Mohammed Rajik Khan ◽  
Atul Sonawane
Keyword(s):  
Complex Geometry ◽  
Construction Safety ◽  
Impact Response ◽  
Fe Model ◽  
Content Type ◽  
Design Engineers ◽  
Head Injury Criteria ◽  
Clear Idea ◽  
Free Falling ◽  
The Impact

Purpose This paper aims to present 3D finite element (FE) simulations of impact loading on a construction safety helmet over a headform to improve the ventilation slots profile in helmet design. Design/methodology/approach Impact response on headforms in three different studies considering ventilation slots of varied profiles and dimensions in helmets with rectangular elliptical and circular slots is compared and analysed. Head injury criteria (HIC) and safety regulations from past literature have been considered to evaluate the impact responses. Findings Simulation results show that a helmet with rectangular ventilation slots achieves a lowest peak impact force of 5941.3 N for a slot area of 170 mm2 as compared to elliptical and circular slots. Research limitations/implications Ventilation slots of simple geometry (rectangular, elliptical and circular) have been considered in this work. Other/complex geometry slots can also be chosen to predict its effect during impact response on a helmet–headform model. Biofidelic head–neck FE model can be developed to achieve precise results. Practical implications The presented work gives a clear idea to design engineers for the selection of ventilation slot profiles to design a construction safety helmet. Social implications Construction safety (CS) helmets are used to reduce injuries on heads of workers at construction sites in the event of free-falling objects. Rectangular ventilation slots in CS helmets as suggested in the work may reduce the risk of injury. Originality/value Results are found in good agreement with the past numerical simulation of impact response on a construction safety helmet over a validated biofidelic head FE model.

scholarly journals Limiting Performance of Helmets for the Prevention of Head Injury

1999 ◽  
Vol 6 (5-6) ◽  
pp. 299-320 ◽  
Author(s):  
Z.Q. Cheng ◽  
W.D. Pilkey ◽  
J.R. Crandall ◽  
C.R. Bass ◽  
K. Darvish
Keyword(s):  
Head Injury ◽  
Skull Fracture ◽  
Head Acceleration ◽  
Head Injury Criterion ◽  
Bicycle Helmets ◽  
Injury Criteria ◽  
Injury Model ◽  
Head Injury Criteria ◽  
The Impact ◽  
The Brain

This is a study of the theoretical optimal (limiting) performance of helmets for the prevention of head injury. A rigid head injury model and a two-mass translational head injury model are employed. Several head injury criteria are utilized, including head acceleration, the head injury criterion (HIC), the energy imparted to the brain which is related to brain injury, and the power developed in the skull that is associated with skull fracture. A helmeted head hitting a rigid surface and a helmeted head hit by a moving object such as a ball are considered. The optimal characteristics of helmets and the impact responses of the helmeted head are investigated computationally. An experiment is conducted on an ensemble of bicycle helmets. Computational results are compared with the experimental results.

scholarly journals An Investigation to Compare the Numerical Model Between Shell and Solid for Honeycomb Light-Weighted Mirror

2010 ◽  
Vol 36 ◽  
pp. 80-85 ◽  
Author(s):  
Yu Chuan Lin ◽  
Long Jeng Lee ◽  
Shenq Tsong Chang ◽  
Yu Cheng Cheng ◽  
Ting Ming Huang
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Surface Deformation ◽  
Optical Design ◽  
Fe Model ◽  
Accurate Analysis ◽  
Element Analysis ◽  
Element Modeling ◽  
Laser Systems ◽  
The Impact

This article reports an accurate analysis approach of finite element modeling and optical modeling. It has been used for design and analysis of many opto-mechanical systems such as large telescopes and laser systems. The approach is to represent mirror surface deformation derived from finite element analysis (FEA) by Zernike polynomials, such that the impact of deformation on optical system performance can be evaluated by optical design and analysis program. The methodology of shell-based and solid-based finite element modeling and the comparison of their results have been described in this paper. The result shows that the deformation of the light-weighted mirror designed by this approach fulfills the requirements of optical design. The simulation results of shell based FE model are in good agreement with those of solid based FE model.

scholarly journals Numerical-Experimental Assessment of a Hybrid FE-MB Model of an Aircraft Seat Sled Test

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
F. Caputo ◽  
A. De Luca ◽  
F. Marulo ◽  
M. Guida ◽  
B. Vitolo
Keyword(s):  
Hybrid Model ◽  
Computing Time ◽  
Fe Model ◽  
Head Acceleration ◽  
Sled Test ◽  
Average Value ◽  
Head Injury Criterion ◽  
Passenger Seat ◽  
Occupant Injury ◽  
Injury Assessment

This paper deals with the development of an established hybrid finite element multibody (FE-MB) model for the simulation of an experimental sled test of a single row of a double passenger seat placed in front of a fuselage bulkhead, by considering a single anthropomorphic Hybrid II 50th dummy arranged on one of the seat places. The numerical investigation has been carried out by focusing on the passenger passive safety. Specifically, the occupant injury assessment has been quantitatively monitored by means of the head injury criterion (HIC), which, based on the average value of the dummy head acceleration during a crash event, should not exceed, according to the standards, the value of 1000. Numerical results provided by the hybrid model have been compared with the experimental ones provided by the Geven S.p.A. company and with the results carried out by a full FE model. The hybrid model simulates with a good level of accuracy the experimental test and allows reducing significantly the computing time with respect to the full FE one.

Occupant Dynamic Responses for Evaluation of Compliance Characteristics of Aircraft Bulkheads

1992 ◽  
Author(s):  
Hamid M. Lankarani ◽  
Deren Ma ◽  
Rajiv Menon
Keyword(s):  
Head Injury ◽  
Contact Force ◽  
Head Injuries ◽  
Element Model ◽  
Dynamic Responses ◽  
Instrument Panel ◽  
Force Model ◽  
Sled Test ◽  
Contact Force Model ◽  
Head Injury Criteria

Abstract One important aspect of aircraft crashworthiness studies is to reduce head injuries to an aircraft occupant in case of a head contact with its surroundings. In view of the significance of this problem, studies of post-crash dynamic behavior of victims and the compliance characteristics of the aircraft bulkhead are necessary in order to reduce severe head injuries. Crash dynamics program SOM-LA/TA, incorporating a dynamic model of the human body with a finite element model of the seat structure was used. Modifications including development of more accurate contact force models and an occupant/seat envelope were performed in SOM-LA/TA. It was then used as an analytical tool for determination of the occupant response and the compliance characteristics of the bulkhead in various crash environments. Correlated studies of analytical simulations with impact sled test results were accomplished. It was observed that the code reasonably predicted the Head-Injury-Criteria (HIC) for the triangular-shaped pulses. A parametric study of the coefficients in the contact force model was then performed in order to obtain a correlation between the HIC and the coefficients in the contact force model. A measure of optimal values for the bulkhead compliances and displacement requirements was thus achieved in order to keep the possibility of head injury as little as possible. This information could in turn be used in the selection of suitable materials for the bulkhead, instrument panel, or interior walls of an aircraft.

Significant Severity Reduction of Side-Impact Injuries by Using ITS Airbags: FE Simulation and Severity Analysis

2002 ◽  
Author(s):  
Tarek A. Omar ◽  
Nabih E. Bedewi ◽  
Azim Eskandarian
Keyword(s):  
Model Performance ◽  
Side Impact ◽  
Fe Model ◽  
Severe Injuries ◽  
Side Impacts ◽  
Head Protection ◽  
Life Saving ◽  
Head Injury Criteria ◽  
Moving Deformable Barrier ◽  
The Impact

The Inflatable Tubular Structure (ITS) airbag is a potentially life-saving device that has been implemented recently in some luxury vehicles. Its main objective is to provide head protection for the front seat occupants against upper side-interior car components. In a previous research conducted by the authors, a nonlinear Finite Element (FE) model for the ITS-airbag system was successfully developed and tested. In the current research, the developed ITS model is combined with a full-scale FE vehicle model and 50th percentile side-impact dummy (SID) model. The combined model is then used to conduct two series of side-impact simulations. The first series included side impacts with narrow objects, i.e. rigid poles, while the second series included side impacts with a Moving Deformable Barrier (MDB) as a wide and deformable object. The effect of the relative position between the dummy and the rigid pole was considered by conducting variety of simulations for two different rigid pole positions and three different dummy positions. The three dummy positions were considered in the side impacts with the MDB. For both impact series, the effect of the impact velocity was considered by conducting each impact scenario at three different velocities. The ITS model performance, in all FE simulations, was fairly similar to the actual ITS performance. The simulation results indicated a significant reduction in the Head Injury Criteria (HIC) of the dummy head due to the ITS-airbag deployment. The life-threatening severity for occupants is usually measured by the Abbreviated Injury Scale (AIS) that ranges from 1 (minor) to 6 (fatal). The AIS indices are calculated in all side impacts. The results demonstrated a significant reduction/elimination in fatalities and severe injuries due to the ITS-airbag performance. The results clearly indicated the great benefits expected from this promising safety device.

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