Study of Heavy Commercial Vehicle Crash Reconstruction
Total Page:16
File Type:pdf, Size:1020Kb
STUDY OF HEAVY COMMERCIAL VEHICLE CRASH RECONSTRUCTION WITH COMPARATIVE ANALYSIS OF PASSENGER VEHICLES A Thesis Presented to the faculty of the Department of Mechanical Engineering California State University, Sacramento Submitted in partial satisfaction of the requirements for the degree of MASTER OF SCIENCE in Mechanical Engineering by Dhanashri Patel SPRING 2020 © 2020 Dhanashri Patel ALL RIGHTS RESERVED ii STUDY OF HEAVY COMMERCIAL VEHICLE CRASH RECONSTRUCTION WITH COMPARATIVE ANALYSIS OF PASSENGER VEHICLES A Thesis by Dhanashri Patel Approved by: __________________________________, Committee Chair Jose Granda __________________________________, Second Reader Troy D. Topping ____________________________ Date iii Student: Dhanashri Patel I certify that this student has met the requirements for format contained in the University format manual, and that this thesis is suitable for electronic submission to the Library, and credit is to be awarded for the thesis. _________________, Graduate Coordinator ___________________ Troy D. Topping Date Department of Mechanical Engineering iv Abstract of STUDY OF HEAVY COMMERCIAL VEHICLE CRASH RECONSTRUCTION WITH COMPARATIVE ANALYSIS OF PASSENGER VEHICLES by Dhanashri Patel Commercial motor vehicles crash investigation and reconstruction technology is a great interest to vehicle design engineers. It is of interest to identify the cause behind heavy vehicle crashes for safer designs. Regulatory agencies like the Commercial Vehicle Safety Alliance (CVSA) is concerned with the public safety. To this aim, this thesis seeks to research this area using state of the art technology and analysis methods based on experimental results and applicable to commercial vehicle crashes for reconstruction purposes. Northwestern University Public Safety department has been a leader in developing the theory in vehicle crashes for passenger cars and the field of heavy vehicles. Heavy vehicles field is still in need of further development. Also, The National Highway Transportation Safety Administration, NHTSA, a government agency has been conducting tests of vehicles of several manufacturers and models to determine crash factors and determine heavy commercial vehicle behavior under collisions. CVSA (Commercial Vehicle Safety Alliance) is another entity, which is a non-profit organization. It is establishing safety v standards for motor vehicles, drivers by providing necessary education and training programs. For this reason, already existing methods and data allows a base structure for developing new methods. Important factors for reconstruction of heavy commercial vehicles have been identified and studied. With the use of already available data, a detailed approach of analysis for important crash factors has been developed. _______________________, Committee Chair Jose Granda _______________________ Date vi ACKNOWLEDGMENTS I would like to thank Professor Jose Granda for his interest in the topic I selected for this thesis. I would also like to express my sincere gratitude to him for his continuous support during my time at California State University, Sacramento. Next, I would like to thank Professor Troy Topping for his guidance. Finally, I would like to thank my husband and parents, whose support and understanding have made me what I am today. vii TABLE OF CONTENTS Page Acknowledgments............................................................................................................. vii List of Tables ..................................................................................................................... xi List of Figures ................................................................................................................... xii Chapter 1. INTRODUCTION ......................................................................................................... 1 1.1 Purpose .............................................................................................................. 1 1.2 Problem Statement ............................................................................................ 2 2. HEAVY-DUTY VEHICLE LAYOUT AND CLASSIFICATION ............................... 3 2.1 Heavy-Duty Vehicle layouts ............................................................................. 3 2.2 Vehicle Classification ....................................................................................... 6 3. BRAKE SYSTEM ....................................................................................................... 10 3.1 Hydraulic Barking System .............................................................................. 10 3.2 Air Braking System......................................................................................... 10 3.3 Reason to Use Air Braking System in Heavy-Duty Vehicles......................... 11 3.4 Brake System in Heavy-Duty Vehicles .......................................................... 11 4. POST-CRASH INSPECTION ..................................................................................... 17 4.1 Commercial Vehicle Safety Alliance .............................................................. 18 4.2 Brake System .................................................................................................. 20 4.2.1 Brake Adjustment Limits ................................................................. 21 viii 4.3 Measure Applied Push-Rod Stroke ................................................................. 24 4.4 Axle Weight Measurement ............................................................................. 26 4.4.1. Dimensional Measurement ............................................................. 28 5. CENTER OF MASS LOCATION ............................................................................... 30 5.1 Center of Mass Lateral Location..................................................................... 34 5.2 Center of Mass Vertical Location ................................................................... 35 6. BRAKING DISTANCE AND SPEED ........................................................................ 37 6.1 Single Adjusted Drag Factor Method ............................................................. 38 6.2 Resultant Drag Factor Method ........................................................................ 39 7. ENERGY ANALYSIS FOR COMMERCIAL VEHICLES ....................................... 45 7.1 Law of Conservation of Energy ...................................................................... 45 7.2 Conservation of Energy in Vehicles ............................................................... 45 8. GENERAL ANALYSIS FOR CONSERVATION OF MOMENTUM ...................... 48 8.1 Momentum ...................................................................................................... 48 8.2 PDOF and ∆ .................................................................................................. 52 9. MOMENTUM ANALYSIS FOR COMMERCIAL VEHICLE .................................. 58 9.1 Velocity/ Speed Factor for Commercial Vehicles .......................................... 58 9.2 PDOF Factor for Commercial Vehicles .......................................................... 59 9.3 Case Study ...................................................................................................... 61 9.3.1 Rear End Collision Case 1 ............................................................... 61 9.3.2 Rear End Collision Case 2 ............................................................... 67 ix 9.3.3 Rear End Collision Case 3 ............................................................... 71 9.3.4 Side Collision Case 4 ....................................................................... 76 9.3.5 Side Collision Case 5 ....................................................................... 81 9.3.6 Side Collision Case 6 ....................................................................... 86 10. CONCLUSIONS......................................................................................................... 92 References ......................................................................................................................... 93 x LIST OF TABLES Tables Page 1. Types of Articulated Vehicles ................................................................................ 5 2. Vehicle Classification System as Per Weight Rating Value ................................... 7 3. Vehicle Classification System as Per Number of Axles ......................................... 9 4. Brake Adjustment Limits for Clamp Type Brake Chamber ................................. 23 5. ECM Report from Freightliner Truck Tractor ...................................................... 62 xi LIST OF FIGURES Figures Page 1. Heavy Duty Truck Tractor with Semitrailer ........................................................... 2 2. Single Unit Truck .................................................................................................... 3 3. Conventional Truck Tractor .................................................................................... 3 4. Cab-Over- Engine Truck Tractor ............................................................................ 4 5. Single Axle Dolly Converter .................................................................................. 6 6. Typical Truck Tractor Semitrailer Braking System.............................................. 12 7. Typical Truck Tractor Air Supply System...........................................................