Airbag system for hip-fracture protection due to falls: mechanical system design and development.

Chan Cheung Shing.Thesis (M.Phil.)--Chinese University of Hong Kong, 2007.Includes bibliographical references (leaves 88-90).Abstracts in English and Chinese.Abstract --- p.iiAcknowledgements --- p.ivTable of Contents --- p.vList of Figures --- p.viiiList of Tables --- p.xiiAbbreviations and Notations --- p.xiiiChapter Chapter 1 --- Introduction --- p.1Chapter 1.1 --- Background and Objective --- p.1Chapter 1.2 --- Contribution --- p.4Chapter 1.3 --- Thesis Outline --- p.5Chapter Chapter 2 --- System Architecture --- p.6Chapter 2.1 --- Conceptual Design --- p.6Chapter 2.2 --- Sensing Device and Fall-Detection Algorithm --- p.7Chapter 2.3 --- Mechanical Part --- p.10Chapter Chapter 3 --- Mechanical Design --- p.11Chapter 3.1 --- Similar Products --- p.11Chapter 3.1.1 --- Airbag Restraining Systems in Automobiles --- p.11Chapter 3.1.2 --- Airbag Jackets for Motorcycle and House Riders --- p.12Chapter 3.2 --- Mechanism adopted --- p.12Chapter 3.2.1 --- Time Requirement of Inflator --- p.12Chapter 3.2.2 --- Mechanism and Design --- p.13Chapter 3.2.3 --- Actuator --- p.14Chapter 3.2.4 --- Punch --- p.15Chapter 3.2.5 --- Airbags --- p.18Chapter 3.2.6 --- Other Mechanisms Tried --- p.19Chapter 3.3 --- Prototype --- p.21Chapter 3.3.1 --- Implementation --- p.21Chapter 3.3.2 --- Demonstration --- p.23Chapter Chapter 4 --- Inflation Estimation --- p.25Chapter 4.1 --- Theory and Model --- p.25Chapter 4.2 --- Validation of Model --- p.28Chapter 4.2.1 --- Testing Equipment --- p.28Chapter 4.2.2 --- Preprocessing of Pressure Sensor Outputs --- p.28Chapter 4.2.3 --- Validation for Basic Equations --- p.29Chapter 4.2.4 --- Adjustment of Discharge Coefficients --- p.36Chapter 4.2.5 --- Validation for Discharging to a Fixed Volume --- p.40Chapter 4.2.6 --- Estimation of the Size of Airbag's Leakage Hole --- p.45Chapter 4.2.7 --- Validation for Discharging to an Airbag --- p.47Chapter 4.2.8 --- Time Delay due to Addition of a Pipe --- p.52Chapter 4.3 --- Summary of Experiments --- p.53Chapter 4.4 --- Limitation of Model --- p.54Chapter 4.5 --- Prediction of Inflation Time and Airbag Pressure --- p.55Chapter 4.5.1 --- Effects of Orifice Size and Vent Size on Airbag Pressure and Volume --- p.55Chapter Chapter 5 --- Force Attenuation Estimation --- p.58Chapter 5.1 --- Theory and Model --- p.58Chapter 5.1.1 --- Kelvin-Voigt Model --- p.59Chapter 5.1.2 --- Standard Linear Solid Support Model --- p.59Chapter 5.2 --- Simple Testing for Validation --- p.61Chapter 5.3 --- Summary of Experiment --- p.64Chapter 5.4 --- Estimation --- p.64Chapter 5.4.1 --- Force Attenuation Ability of Prototype --- p.64Chapter 5.4.2 --- Minimum Airbag Volume and Pressure Required to Reduce the Force --- p.65Chapter Chapter 6 --- Future Work --- p.66Chapter 6.1 --- Impact Test for Airbag System --- p.66Chapter 6.2 --- The Effective Mass of the Target User --- p.67Chapter 6.3 --- The Motion Data Collection --- p.68Chapter 6.4 --- Modification in the Inflator --- p.69Chapter Chapter 7 --- Conclusion --- p.70Appendix A Review of Basic Thermodynamics and Fluid Dynamics --- p.72Chapter A.1 --- Thermodynamics --- p.72Chapter A.2 --- Fluid Mechanics: Incompressible and Compressible Flow --- p.75Appendix B Derivation of Equations --- p.77Chapter B.1 --- Mass Flow Rate Equations --- p.77Chapter B.2 --- Relationship between Rate of Changes of Airbag Pressure and Volume --- p.80Chapter B.3 --- Pressure Change of Compressed Gas Cylinder --- p.82Chapter B.4 --- Dominating Factors in the Mass Flow Rate Equation --- p.83Appendix C Dimensions of Inflator --- p.85Appendix D Experimental Data --- p.8