effect of aircraft seat belt modeling techniques on the crash dynamics and injury criteria for a hybrid

97 Pages·2009·5.95 MB·English

by  Amit A. Deshpande

EFFECT OF AIRCRAFT SEAT BELT MODELING TECHNIQUES ON THE CRASH
DYNAMICS AND INJURY CRITERIA FOR A HYBRID III 50TH PERCENTILE FAA
DUMMY

A Thesis by
Amit A. Deshpande
Bachelors of Engineering, Pune University, Pune, 2003

Submitted to the Department of Mechanical Engineering
and the faculty of the Graduate School of
Wichita State University
in partial fulfillment of
the requirements for the degree of
Master of Science

December 2006
© Copyright 2006 by Amit Achyut Deshpande

All Rights Reserved

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EFFECT OF AIRCRAFT SEAT BELT MODELING TECHNIQUES ON THE CRASH
DYNAMICS AND INJURY CRITERIA FOR A HYBRID III 50TH PERCENTILE FAA
DUMMY

The following faculty have examined the final copy of this thesis for form and content and
recommend that it be accepted in partial fulfillment of the requirements for the degree of Master
of Science, with a major in Mechanical Engineering.

Dr. Hamid M. Lankarani, Committee Chair

Dr. Babak Minaie, Committee Member

Dr. Bayram Yildirim, Committee Member

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DEDICATION

The work is dedicated to

My Parents and my brother Rohit
For their unconditional support, love and encouragement

My Advisor

Dr. Hamid Lankarani
For supporting me the way my parents do

Dr. Gerardo Olivares
For his irreplaceable coaching

All my dearest friends in Pune, India
All of my Room-mates and friends in Comp-Mech 206 Lab in Wichita

The wind has settled, the blossoms have flourished,
Birds sing, the mountains grow dark;
this is the wondrous power of GOD.
- Rig Veda

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ACKNOWLEDGEMENTS

I would like to thank my advisor, Dr. Hamid Lankarani for his support, inspiration and
encouragement throughout my studies at Wichita State. It is due to his support and timely
guidance. I would also like to thanks to Dr. Gerardo Olivares for his support and coaching which
was irreplaceable in completing this research and are greatly appreciated.
I will also like to extend my gratitude to members of my committee Dr. Bob Minaie and
Dr. Bayram Yildirim for their valuable comments and suggestions in presenting my research
work as a complete these.
I would also like to extend my gratitude to all my colleagues and friends who supported
me through out my master’s degree.

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ABSTRACT

This research attempts to develop and to study the effects of the change in the same type
of belt models on the injury criteria. To study the effects, total of six MADYMO models with
three different belt models are generated. The models consist of MADYMO generated belt
segments, finite element belt, and finite element belt without belt joining buckle. These models
are studied on the basis of the Federal Aviation Regulations FAR Part 25.562 general and
emergency landing conditions. The Hybrid III 50th percentile FAA dummy is used for the study
as it is more compatible than Hybrid III 50th percentile dummy for the aviation purpose.
To create the belts, various types of software and approaches are used and their results
then are compared with the mechanical test or standards written by Federal Aviation
Administration (FAA) or National Highway Traffic Safety Administration (NHTSA). This
research attempts to find out how the belt models affects the injury level of an occupant during
frontal crash impact in aviation accident.
To support the results in validation process, the data of four actual crash lab testing
carried out at National Institute for Aviation Research is used. The validations are carried out on
the basis of the statistical test and comparison of the dummy kinematics of the actual mechanical
tests and simulation. The methods of correlation coefficient and peak value measurement of the
acceleration, forces and moments experienced by the occupant are used to validate the models.
The injury levels obtained by the simulation models are also compared with the critical values
regulated by the Federal Aviation Administration (FAA).

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TABLE OF CONTENTS

Chapter Page

1. INTRODUCTION ...............................................................................................................1

1.1 Motivation ................................................................................................................1
1.2 Objective ..................................................................................................................2
1.3 General Injury Mechanisms In Crash Scenarios ......................................................2
1.3.1 Skull Fracture .................................................................................................2
1.3.2 Focal Brain Injury ..........................................................................................3
1.3.3 Diffuse Brain Injury .......................................................................................3
1.4 General Injury Criterion ...........................................................................................3
1.4.1 Head Injury Criterion .....................................................................................3
1.4.2 Neck Injury Criterion .....................................................................................4
1.4.3 Thoracic Trauma Index ..................................................................................4
1.4.4 Viscous Injury Response (VC) ......................................................................5
1.4.4 Femur Force Criterion....................................................................................6
1.4.6 Chest 3ms Criterion .......................................................................................6
1.4.7 Chest Deflection Criterion .............................................................................6

2. TEST PROCEDURES .........................................................................................................7

2.1 Introduction ..............................................................................................................7
2.2 Pass/Fail Criteria for FAR Part 25.562 ....................................................................7
2.3 Definitions................................................................................................................8
2.4 General Test Procedures ..........................................................................................9
2.5 Dynamic Test Procedures ......................................................................................11
2.5.1 Test Configuration I .....................................................................................11
2.5.2 Test Configuration II ....................................................................................12
2.6 Actual Test Set Up .................................................................................................12
2.6.1 National Institute for Aviation Research (NIAR) Sled Facility ...................12
2.6.2 Comparison and selection of the dummy .....................................................14

3. COMPUTATIONAL TOOLS ...........................................................................................16

3.1 MADYMO .............................................................................................................16
3.2 Systems in MADYMO ..........................................................................................19
3.2.1 Reference/ Inertial Space .............................................................................19
3.2.2 Null System ..................................................................................................19
3.2.3 Multi-body Systems .....................................................................................20
3.3.1 Numerical Integration Methods in MADYMO ...........................................23
3.3 Finite Element Modeling in MADYMO................................................................24
3.4 Dummy Database ...................................................................................................25
3.5 Scaling of Dummies ...............................................................................................27
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TABLE OF CONTENTS (continued)

Chapter Page

3.6 Injury Parameters ...................................................................................................28
3.7 HYPERMESH .......................................................................................................30
3.7.1 Geometry Terminology .................................................................................32

4. METHODOLOGY ............................................................................................................34

4.1 Need For Simulation ..............................................................................................34
4.2 Flow-Chart For Methodology ................................................................................35
4.3 Modeling of Seat ....................................................................................................35
4.4 Simulation Model and Characteristics ...................................................................36
4.4.1 Model 1,2,3 for emergency conditions ........................................................37
4.4.2 Model 1 for general conditions ....................................................................39
4.4.3 Model 2 for general conditions ....................................................................40
4.4.4 Model 3 for general conditions ....................................................................41
4.5 Selection and Positioning of Dummy ....................................................................42
4.6 Head Profile ...........................................................................................................43
4.7 Design and Routing of the Belt ..............................................................................44
4.8 Seat Belt Position ...................................................................................................46
4.9 Sled Pulses .............................................................................................................47
4.9.1 Sled Pulse for Test configuration I ..............................................................47
4.9.2 Sled Pulse for Test configuration II .............................................................48
4.10 Selection of Characteristics for MADYMO Model ...............................................49
4.10.1 Contact Characteristics for Ellipsoid Model ..............................................49
4.10.2 Contact Characteristics for Seat Surfaces ..................................................49
4.10.3 Contact Characteristics for Belt Attachment Buckle .................................50
4.10.4 Contact Characteristics for belt ..................................................................51

5. VALIDATION ...................................................................................................................52

5.1 Introduction ...........................................................................................................52
5.2 Validation Methods ................................................................................................52
5.2.1 Correlation Coefficient ................................................................................53
5.2.2 Injury Parameter...........................................................................................53
5.2.3 Peak Value Validation .................................................................................54
5.2.4 Relation between Average Signals ..............................................................54
5.2.5 Standard Deviation of Residuals ..................................................................55
5.2.6 Maximum Residuals ....................................................................................55

6. RESULTS AND DISCUSSIONS ......................................................................................56

6.1 Introduction ............................................................................................................56
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TABLE OF CONTENTS (continued)

Chapter Page

6.2 Comparison of the signals based on Dummy Kinematics ....................................56
6.3 Comparison of the signals based on Coefficient of Correlation ............................63
6.4 Comparison of the signals based on Peak Value Criteria ......................................64

7. POTENTIAL APPLICATIONS ........................................................................................70

7.1 Applications ...........................................................................................................70

8. CONCLUSIONS AND RECOMMENDATIONS ............................................................72
8.1 Introduction ............................................................................................................72
8.2 Conclusions ............................................................................................................72
8.3 Recommendations ..................................................................................................74
9. LIST OF REFERENCES ...................................................................................................77
APPENDIX A: COMPARISONS OF THE PROFILES
FOR TEST CONFIGURATION I .....................................................................................80
APPENDIX B: COMPARISONS OF THE PROFILES
FOR TEST CONFIGURATION II ....................................................................................83

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LIST OF TABLES

Table Page

1. Test Matrix .........................................................................................................................37
2. Load-deformation Values for the Belt ...............................................................................46
3. Contact Characteristic values for Seat ...............................................................................49
4. Contact Characteristic Belt Attaching Buckle ...................................................................50
5. Comparison based on Coefficient of Correlation ..............................................................63
6. Peak Value measurement for Test configuration I ............................................................66
7. Peak Value validation for Test Configuration I .................................................................67
8. Peak Value measurement for test Configuration II ............................................................68
9. Peak Value validation for Test Configuration II ................................................................69
10. Summary Results and Pass/Fail Criteria Values for FAR 25.562 .....................................72
11. Summary of all the comparisons........................................................................................73

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