Bus Crash Analysis

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Study of Frontal Impact of a Passenger Bus

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Bus Crash Analysis

  1. 1. Final Project Presentation Study of Frontal Impact of a Passenger Bus Manjunath Rao T S BBB0906034 M. Sc. (Engg.) in Automotive Engineering Academic Guide : Mr. Madan J Project Manager, SASTECH, Bangalore
  2. 2. Aim and Objectives of the Project Aim : To study frontal impact of a passenger bus and to recommend methods to improve safety Objectives : <ul><li>To review the literature on effects of impact on passenger buses </li></ul><ul><li>To study relevant analytical models that are available in the literature </li></ul><ul><li>To simulate the frontal impact behavior of the passenger bus </li></ul><ul><li>To analyze and interpret the results with the experimental data available in literatures </li></ul><ul><li>To suggest some design changes in order to improve structure safety </li></ul>
  3. 3. Methodology <ul><li>Literature review on Crashworthiness of bus will be carried out by referring reviewed journals, books and related documents </li></ul><ul><li>Geometric modeling of bus structure will be carried out using CATIA V5 R16 / Pro-E 2001 </li></ul><ul><li>FE model generation for all the parts will be carried out using Hypermesh 7.0 </li></ul><ul><li>Input deck for simulation will be created using Hypermesh 7.0 </li></ul><ul><li>Frontal impact simulation will be carried out using LS-DYNA and post processing will be carried out using LS-POST </li></ul><ul><li>Investigation of the analysis results in order to improve the crashworthiness </li></ul>
  4. 4. Introduction <ul><li>Among all the accidents that take place, frontal impact has got a major share of 40%. Again in these conditions the injury caused to drivers or the front passenger is extremely high. </li></ul><ul><li>In automotive domain more emphasis has been given to the safety of passenger cars, but seldom the importance is given to passenger bus. </li></ul><ul><li>Though the damage due to frontal impact of the bus is lesser when compared to other vehicles, the consequences of such impact on drivers are fatal. </li></ul><ul><li>According to the study during frontal impact of bus more than 80% of drivers die than any other members of the bus. </li></ul><ul><li>In frontal impact scenario more significance should be given on structural integrity, and hence this project work is carried out in this direction. </li></ul>
  5. 5. Design Bus Specifications: 500 Engine & subsystems 400 Powertrain 300 Drivetrain 160 litres Fuel Tank Capacity 10160 Permissible R.A.W. 5080 Permissible F.A.W. 12500 Max. G.V.W 4010 Bare chassis kerb weight   Weights (kg.)   53 Max. Seating capacity 240-275 Min. ground clearance in mm 2050 Track rear 1930 Track front 2375 Max. width 10309 Overall length 3200 Rear overhang 1775 Front overhang 5334 Wheel base Dimension (mm) (as per IS 9435) LPO 1510/55
  6. 6. Construction
  7. 7. Material : Structural steel Std. : IS 2062 Design
  8. 8. Geometric modeling has been carried out using Pro-E 2001 software. All the geometric datas were collected from “KMS Coach Builders Pvt. Ltd.” (Official partners of KSRTC for coach building). All the structural details were as per the 2D drawings provided. Various views of modeled bus is shown in following sections: Geometric Modeling: Design
  9. 9. <ul><li>Parts which are not directly related to the frontal impact or which have no significant effect on the final output have not been considered. </li></ul><ul><li>All the sub-systems that were discarded in design process have been considered as lumped mass at appropriate locations. </li></ul><ul><li>All structural designs are as per the documents obtained from KSRTC. </li></ul>Assumptions: Design
  10. 10. Meshed bus with shell elements and 1-D Beam Elements FE Model 2963 1D Elements 105 Total Parts 260779 Shell Elements 264139 Total Elements
  11. 11. Mass Elements Rigid Elements FE Model Parts replaced with Mass Element
  12. 12. Boundary Conditions Contact interface is done by defining the box and providing *CONTACT_AUTOMATIC_SINGLE_SURFACE
  13. 13. Friction between tyres and rigid plane Boundary Conditions
  14. 14. Simulation Inputs Material Properties assigned Simulation Inputs 0.2 secs Simulation time 30 km/hr Velocity 7.85e-6 3.55e-6 7.85e-6 Density Kg/mm3 210 210 210 Young’s modulus GPa 0.3 0.3 0.3 Poisson’s Ration 350 MAT_PIECEWISE_LINEAR_PLASTICITY MAT_24 MAT_RIGID MAT_ELASTIC MAT_1 Yield Stress MPa Material
  15. 15. Simulation & Results
  16. 16. Simulation & Results (contd.)
  17. 18. Simulation & Results (contd.)
  18. 19. Simulation & Results (contd.)
  19. 20. Simulation & Results (contd.)
  20. 21. Simulation & Results (contd.)
  21. 22. Design Improvement Comparison of various crush initiators
  22. 23. Design Improvement Comparison of bead type crush initiators
  23. 24. Simulation & Results (contd.)
  24. 25. Simulation & Results (contd.)
  25. 26. Simulation & Results (contd.) Comparison of Load pattern with both designs
  26. 27. Conclusion <ul><li>It has been understood that the load distribution on the structures are not uniform, which lays down the road to improvement in buckling characteristics of the structures. </li></ul><ul><li>By having crush initiators, the peak load can be reduced. This has been achieved by implementing such designs to some of the structural members, which is around 4% reduction in peak load. </li></ul><ul><li>The design improvement that has been achieved is just for few structural elements, if this approach is followed for many other key structural members then the design could be far superior. </li></ul><ul><li>The floor deceleration is around 12g, which is well in agreement with ECE R80 regulation that specifies the floor deceleration to be around 8-12g at 30km/hr. </li></ul>
  27. 28. Future Work <ul><li>In today’s automotive body engineering advancements there are various systems that improves the crashworthiness of the vehicle significantly. Many such systems can be implemented in order improve the structural safety. </li></ul><ul><li>Simulation of the frontal impact behavior of the passenger bus can be carried out by considering various subsystems of the vehicle like engines, transmission, steering system etc.. </li></ul><ul><li>Positioning of dummy in the driver’s seat helps in finding the injury parameters. </li></ul><ul><li>Seat belt concept in passenger bus is an alien concept in India, efforts can be made in developing such a concept. </li></ul><ul><li>More understanding is required in order to improve the structural behavior of chassis, which can be detrimental in overall design. </li></ul>
  28. 29. References <ul><ul><li>[1] VINCZE-PAP Sándor, CSISZÁR András, “ Real and Simulated Crashworthiness Tests on Buses ” ESV 19th Conference, NHTSA, Paper Number 05-023, 2005 </li></ul></ul><ul><ul><li>[2] Jeffrey C. Elias, Lisa K. Sullivan, Linda B. McCray, “ Large School Bus Safety Restraint Evaluation ” NHTSA, Paper No. 345, 2001 </li></ul></ul><ul><ul><li>[3] Yoshiriro Sukegawa, Fujio Matsukawa, Takeshi Kuboike, Motomu Oki, “ Heavy Duty Vehicle Crash Test Method in Japan ”, NHTSA, Paper number 98-S4-O-13, 1998 </li></ul></ul><ul><ul><li>[4] Mátyás Matolcsy, “ Technical Questions Of Bus Safety Bumpers ”, NHTSA, Paper number 05-0161, 2005 </li></ul></ul><ul><ul><li>[5] Willibrordus J. Witteman “ Improved Vehicle Crashworthiness Design by Control of the Energy Absorption for Different Collision Situations” </li></ul></ul>
  29. 30. Thank You

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