evaluation of radioss human model (humos ii) for aircraft side facing seats applications
DESCRIPTION
The Federal Aviation Administration (FAA) has defined the requirements for aircraft seat certification concerning the emergency landing dynamic conditions for different categories of airplanes and rotorcrafts. This regulation is primarily focused on backward and forward facing seats. In order to make the certification tests, the aircraft manufacturers use Anthropomorphic Test Devices (ATD), representative of the human body. Numerical modelling tools such as finite elements models are now used to facilitate the evaluation of aircrafts seating systems (AC 20-146 2003). In that case, numerical ATD are used. However, they are not as biofidelic as human numerical model. The benefits of human body models in term of realistic behavior, injuries prediction or specific organs studies are important. In 2006, the European Commission, with many partners from the automotive industry, sponsored the creation of the Human Model for Safety 2 (HUMOS 2), a human finite element model. This model has been then adapted to be used in aircraft crash scenario (Njilie 2012), leading to the HUMOS2 AERO model. It has been validated in FAA fontal and vertical load cases conditions. However, in the field of business jets, side-facing seats are quite popular. The risk of injury is totally different between side facing and forward facing seats (Philippens 2011). As a consequence, there is need to understand more precisely the human behavior in these specific conditions of impact during survivable emergency landing. The purpose of this study was to adapt and improve the HUMOS2 AERO model to side facing tests conditions and to investigate the injury mechanism. The other objective was to compare the response of the human model to the ES2-re model, a side impact ATD.TRANSCRIPT
Innovation Intelligence®
Evaluation of RADIOSS Human Model
(HUMOS II) for Aircraft Side Facing Seats
applications
Anaïs GARO, PhD ; Franck NJILIE, PhD ; Martin Poupeney
Altair Development France
Copyright © 2012 Altair Engineering. Inc. Proprietary and Confidential. All rights reserved.
Introduction : Context
• Federal Aviation Administration (FAA) regulations
primarily focus on injury mitigation in frontal and
vertical ”survivable” impacts (Title 14 of the CFR
parts 25.562, 23.562, 27.562, 29.562)
• Necessity to provide similar protection to passenger
in side facing seat
• A Project was conducted by the FAA Civil Aerospace
Medical Institute (CAMI) to evaluate the suitability of
a side impact dummy, the ES2, in assessing injury
risk in a typical side facing seat configuration
• The purpose on this work was to evaluate RADIOSS
Human body model in similar test conditions
• HUMOS II might further be used to investigate injury
mechanism and develop adequate injury criteria for
aircraft side facing crash scenarios
Copyright © 2012 Altair Engineering. Inc. Proprietary and Confidential. All rights reserved.
RADIOSS HUMOS II (HUman MOdel for Safety) : Created for
automotive crash applications
Adaptation of the model seating posture for aerospace applications
RADIOSS HUMOS II AERO model
RADIOSS HUMOS II model
Sitting height
(mm)
Standing height
(mm)
Weight
(kg)
HUMOS subject 920 1730 77
50th Percentile
European male 915 1750 75.5
BCS
Rotate
Center of
rotation
Copyright © 2012 Altair Engineering. Inc. Proprietary and Confidential. All rights reserved.
RADIOSS HUMOS II model
Accelerometers : head, pelvis, upper and the lower spine
Rib deflection transducers
Force: lumbar and pubic
L4
L5
Joint
Disc
Copyright © 2012 Altair Engineering. Inc. Proprietary and Confidential. All rights reserved.
Load cases based on CAMI (Civil Aerospace Medical Institute) work
• Restraint system : Conventional three point belt
• 16 g, 44 ft/s, horizontal impact specified in 14 CFR part 25.562 (without yaw)
• Seats covered with foam cushion
Load cases : typical aircraft side facing scenarios
Close wall test Arm-rest test
Assessment of injury potential in aircraft side-facing seats using the ES2 anthropomorphic test dummy, DeWeese R. and Moorcroft D., 2007, FAA
Copyright © 2012 Altair Engineering. Inc. Proprietary and Confidential. All rights reserved.
Results and discussion : close wall
Kinematics and Accelerations
Copyright © 2012 Altair Engineering. Inc. Proprietary and Confidential. All rights reserved.
Fractures
Results and discussion : close wall
Copyright © 2012 Altair Engineering. Inc. Proprietary and Confidential. All rights reserved.
Results and discussion : close wall
Forces
Pubic Resultant force
Lower lumbar Fy
Copyright © 2012 Altair Engineering. Inc. Proprietary and Confidential. All rights reserved.
Rib deflection
→ Rib cage modeling
Results and discussion : close wall
Copyright © 2012 Altair Engineering. Inc. Proprietary and Confidential. All rights reserved.
Kinematics
Results and discussion : Arm rest
Copyright © 2012 Altair Engineering. Inc. Proprietary and Confidential. All rights reserved.
Acceleration
Forces
Results and discussion : Arm rest
Copyright © 2012 Altair Engineering. Inc. Proprietary and Confidential. All rights reserved.
Rib deflection
→ Kinematics differences
Results and discussion : Arm rest
Copyright © 2012 Altair Engineering. Inc. Proprietary and Confidential. All rights reserved.
Conclusion
RADIOSS HUMOS II aerospace model is updated and successfully
evaluated within aerospace context : forward and side facing test
configuration
The updated HUMOS II model allows to capture and predict potential
injuries ATDs such as ES 2 cannot highlight due to their stiffness
However, further validations are required using PMHS test data in
aerospace load cases