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The MiniBaja Project

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SAE Specifications for the Mini-Baja ... Perform simulation on all Mini-Baja models. Analyze and Evaluate the stress distributions. ... Model Used: Full ... – PowerPoint PPT presentation

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Title: The MiniBaja Project


1
The Mini-Baja Project
  • Patrick Chittchang
  • Pratik Desai
  • Rehan Kazmi
  • Brian Mok

ENME 471, Dr. Panos Charalambides
2
Outline
  • Project Objectives
  • Design Methodology
  • Boundary Conditions
  • Mini-Baja Frames
  • Results
  • Conclusions
  • Questions

3
Project Objectives
  • To develop a frame that conforms to the SAE
    standards
  • To develop a frame that is streamlined,
    low-weight and safe for the driver and other
    competitors.
  • Optimize the Stress-Weight tradeoff.
  • Cost effectiveness.

4
SAE Specifications for the Mini-Baja
  • The roll cage must satisfy SAE requirements for
    space and strength (minimum size 1-inch ODx0.083
    thickness DOM steel tubing).
  • Side bars with a height of 8-inches (min.) above
    the lowest point of the seat of the pants of
    the driver.
  • Maximum time for a driver to exit the vehicle is
    five seconds.
  • Transportable via standard pickup trucks with
    eight foot beds.
  • Consider the aesthetics of the frame as well as
    the strength and size requirements.

5
Design Tasks
  • Perform simulation on all Mini-Baja models.
  • Analyze and Evaluate the stress distributions.
  • Drivers safety First
  • Optimize Stress Vs Weight relationship.
  • Modify and finalize the model

6
Model Development
  • Pre-Processing
  • Element Linear Isotropic 1 D Beam Element with
    Circular Cross-Section
  • Material 1020 DOM Steel (Driven Over Mandrel)
  • Apply Boundary Conditions
  • Symmetry/
  • Anti-Symmetry
  • Processing
  • Meshing
  • Solve the model using I-DEAS
  • Post Processing
  • Data Analysis
  • Make informed choices to meet the design objective

7
Loading Cases
  • Six loading conditions
  • Rollover
  • Front Bump
  • Rear Bump
  • Frontal Collision
  • Heave
  • Twist Ditch

8
Frontal Collision Test
Test Frontal Collision Model used Half
model Condition Symmetry Loading a uniformly
distributed 1680 lb force in X-direction at the
front of the vehicle Boundary Condition Rear
cornerTrans XYZ0 Opp.Rear cornerTrans
XY0 Front cornerTrans Y0 Opp.Front corner
Trans YZ0
9
Heave Loading
  • Test Heave Loading
  • Model used Half model
  • Loading Engine and Driver load (100 210)3
    630 lbs
  • Boundary Conditions
  • One rear corner X,Y Z 0
  • Opposite rear corner X Y 0
  • One Front Corner Y 0

10
Rollover Test
Test Rollover Model Used Full Loading Rollover
loading considered is 9.42G acting on one of the
top front joints of the frame Vertical load
4200lbs Fore Aft load 3080lbs Lateral load
840lbs
11
One Front Wheel Bump Test
  • Test Front Bump
  • Model used Full model
  • Loading a point force of 1680
  • lbs in the Y-direction
  • of the front corner node
  • Boundary Conditions
  • Rear cornerTrans XYZ0
  • Opp.Rear cornerTrans XY0
  • Opp.Front corner Trans YZ0
  • Other corner Simulate the force equal to 3 X
    Total Vehicle Weight 1680 lbs

12
One Rear Wheel Bump Test
  • Test Rear Bump
  • Model used Full model
  • Loading 1680 lbs in Y-direction
  • of the rear corner node
  • Boundary Conditions
  • Front cornerTrans XYZ0
  • Opposite Front corner
  • Trans XY0
  • Rear corner Trans YZ0
  • Other corner Simulate the force equal to 3 X
    Total Vehicle Weight 1680 lbs

13
Twist Ditch Test
  • Test Twist Ditch
  • Model used Half model (Anti-Symmetric)
  • Loading Engine and Driver load (100 210)3
    630 lbs
  • Boundary Conditions
  • One rear corner X,Y Z 0
  • Opposite rear corner X Y 0
  • One Front Corner Y 0

14
Designed Frames
  • Model 1- Bubble
  • This is the base model given to us by the
    problem definition
  • Model 2-Buttercup
  • An over-designed version in order to first pass
    the model successfully through the six severe
    loading conditions
  • Model 3-Blossom
  • Getting the right mix between stress reduction
    and weight optimization paradigm

15
Model 1 - Bubble
  • Model 1 (the original frame)
  • Elements are all 1 x 0.083 inch tubing
  • Six loading tests

16
Nodes and Elements-Bubble
Elements are 1 x 0.083 tubing throughout the frame
17
Bubble Results
  • Passed
  • Frontal Collision
  • Heave
  • Twist Ditch
  • Failed
  • Rollover 34 elements
  • Front Bump 16 elements
  • Rear Bump 25 elements

18
Rollover Test
Real Time Model Displacement
Von-Mises Stress
Green Pass Red Failed
19
Model 1 test results and observations
  • Roll over and Bump tests were the most severe
  • Von Mises Stress is used as a critical design
    parameter
  • The model needs to be beefed up in the drivers
    compartment
  • Decide viable way to increase the stiffness of
    the overall structure
  • Essentially the major goal for the next step was
    to pass the model
  • Minimization of overall weight

20
Modeling Tasks for Model 2
  • Reconfigure the roll cage.
  • Making sure the frame passes rollover and bump
    tests.
  • Add cross members to the top of the drivers
    compartment and back windshield in order to
    triangulate the stresses
  • Separate the drivers compartment from the engine
    compartment by adding a beam.
  • Add members to the side of the drivers carriage
    (below).
  • Resist the temptation to add a cross member that
    would block the drivers access in and out of the
    Mini-Baja.

21
Model 2- Buttercup
Tube Sizes Induces Drastic Weight Changes
22
Test results and Observation
  • Buttercup passed all the tests
  • Weight 128 lbs
  • 5 types of different Tubes

23
Modeling Tasks for Model 3
  • Design Reform
  • Experiment with curve beam
  • Difficulties
  • Solutions
  • Point Load
  • Distributed Load

24
Model 3
Curvature
Curve makes everything Beautiful
25
Rollover Test Distributed Load
26
Rollover Test Point Load
27
Blossom Test Results
  • Strength Weight and Aesthetic
  • The weight 120lbs
  • 4 different Types of Tube
  • Passed all the six loading cases
  • Aerodynamic shape

28
Comparison
29
Conclusions
  • Bubble was the lightest but it failed miserably
    under most of the loading conditions
  • The second model-Buttercup was developed by
    modifying the first model making changes in the
    tube X-section and adding more elements. It
    passed all the loading conditions but was really
    heavy to be used as our final design
  • Blossom Great Looks with Excellent Performance

30
Questions?
31
Credits
We extend our sincere thanks to all the people
who made this project possible
Our special thanks to Dr. Panos Charalambides for
providing the opportunity to gain an insight into
the finite elements intricacies
We also would like to thank UMBC for providing us
with the facilities required to complete the
project AND FINALLY
We wish all the best to our classmates who are
graduating this semester . -GOOD LUCK GUYS
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