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Y Link Presentation - Senior Design

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Conceptual Design Review for my senior design project

Conceptual Design Review for my senior design project

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  • Introduce our selves, Dr. Soliman and our project with an overview of project (what is fits)
  • This is the outline for the presentation and what topics are coveredProblem statement – what the problem is and what is coversDesign modifications – what we plan on changing and gain in doing this projectTasks – Things to be done in order to determine our successMeasure of performance – Items that will determine if the project was a successPossible solutions – Different ideas that were generated in order to accomplish our goalsJustification of design – Why we chose the solution we didDesign – Our design to accomplish our goalRisk and Mitigation – Things that could be a bump or “show stopper” during the project
  • This is the problem that we are occurring. Due to the relatively short length of the OEM control arms with a lifted Jeep the axle is limited to a relatively short range of motion before binding. Along with its short range of motion the road harshness is transmitted more directly though the LCA due to its angle relative to horizontal.
  • This slide illustrates the problems due to the length of the OEM arms and the height of the vehicle. As you can see from the picture 1 even with the weight of the vehicle on the springs the angle of the control arms are relatively steep, creating binding in the suspension and steering. Figure 1 illustrates that with a longer arm the amount of suspension travel due to horizontal distance is greatly increased over the OEM control arm. Figure 1 also shows an indicated force from the road and its relative resultant forces that are transmitted directly into the chassis.
  • This is what the proposed design will accomplish. A measureable increase in axle articulation, droop and improved ride quality. While the system will be easily integrated with a bolt-on design with the ability to be adjusted for alignment of axle location but caster angle.
  • Here are the tasks that will have to be achieved in order to measure our products worth and that it is acceptable. The systems’ simulated stresses will be assessed by Ansys and stress analysis. Also to evaluate the systems articulation it will be post measured using a Ramp Travel Index RTI for short, along with re-analysis of accelerometer data used to measure ride quality.

Y Link Presentation - Senior Design Y Link Presentation - Senior Design Presentation Transcript

  • A New Design for Improving Suspension Performance
    Y-Link Control Arm and Cross Member Project
    Jesse Parnell
    Matthew Etter
    Advisor: Dr. Ahmed Soliman
    University of North Carolina at Charlotte
    1
  • Outline
    Problem Statement
    Design Goals
    Techniques to Measure Success
    Measures of Performance
    Articulation
    Ride Quality
    Possible Solutions
    Justification of Design
    Design
    Risk and Mitigation
    Conclusion
    2
  • The Problem
    The Original Equipment Manufacturer (OEM) suspension design on the 84-01 Jeep Cherokee features a limited suspension travel due to short Lower Control Arm (LCA) design
    This design causes the LCA to limit axle movement
    As a result there exists binding in the suspension and steering linkage
    Due to the wide angle of rotation the force components that are reflected on the chassis are high
    3
  • The Problem
    Picture 1: Illustrates OEM style upper and lower control arms
    http://www.off-road.com/jeep/cherokee/2001/10_oct/longarm/Stock_Arms.jpg
    Figure 1: Created in Visio to compare OEM arc radius to long arm arc radius
    4
  • Design Goals
    Increase articulation and suspension travel
    A quantifiable increase in articulation
    Improve ride quality
    Reduce the road roughness felt by vehicle occupants
    Increase strength over OEM
    Adjustable for alignment
    The system must include a means for adjustment
    Increased ground clearance
    Compare measurements of factory design to improved design
    Completely bolt-on design with simple integration
    This design modification should be easily integrated
    5
  • Techniques to Measure Success
    Evaluate Articulation
    Ramp Travel Index (RTI)
    Measure Ride Quality
    Accelerometer
    Simulate stresses
    Ansys
    Stress Analysis
    6
  • Articulation Measurement
    Ramp Travel Index (RTI)
    Ability to measure vehicles axle articulation
    Typical 20 degree ramp standard
    Current RTI score for Jeep Cherokee with 4.5” lift is 647
    Figure 2: How to calculate RTI score using 20 degree ramp
    Picture 2: Measuring Jeep Cherokee with 4.5” lift on RTI
    7
  • Measuring Ride Quality
    • Magnitude of 3 axis Accelerometer readings were used to measure ride quality
    • Using the magnitude eliminates any need for directional calibration
    • Standardized “bumps”
    • 2x4 lumber (1.5” high)
    • One and two wheel impacts
    • 25 mph set speed
    • 35 psi tire pressure
    • Sampling rate was set to 20 Hz
    • iPhone secured in place
    • iPhone Accelerometer Specifications**:
    • STMicroelectronicsLIS331DL
    • 3 axis data collection
    • ± 2g range
    • Embedded high pass filter eliminates gravitational readings
    • Data will be collected in similar fashion to compare ride quality after build
    Figure 3: Screen Shot of iPhone accelerometer application
    8
  • Accelerometer data
    Plot 1: Accelerometer impact data of standardized bumps using iPhone application
    9
  • Possible solutions
    Drop brackets
    Longer upper and lower control arms
    Straight Longer lower control arms with a cross member
    • Longer bent style control arm with a Y-link and cross member
    Picture 3: Drop brackets disadvantage is the decrease in ground clearance http://store.4wheelingplus.com/images/jeep-xj-Control-arm-drop-brackets2.jpg
    10
  • Justification
    Simplified single arm design
    Increased ground clearance
    Enhanced protection
    Improved ride comfort
    Extended articulation
    11
  • Proposed Design
    Figure 4: Proposed Y-link Control Arm modeled in Solidworks
    Dual function of Y-link control arm as upper and lower control arm
    Increased ground clearance
    Adjustable for alignment purposes
    Longer than factory LCA, increasing articulation
    12
  • Risk and Mitigation
    Bent style introduces stresses
    Simulate stresses using Ansys
    Vehicle stability
    Factory sway bar will provide stability
    Coil spring float
    Retaining straps to maintain spring position
    13
  • References
    **http://www.st.com/stonline/products/literature/ds/13951.pdf
    http://www.off-road.com/jeep/cherokee/2001/10_oct/longarm/Stock_Arms.jpg
    http://store.4wheelingplus.com/images/jeep-xj-Control-arm-drop-brackets2.jpg
    http://www.jeeps-offroad.com/reader-rigs/albums/album83/fullsizeflex2.sized.jpg
    14
    Suggestions?
    Picture 4: Illustrating the desired results
    http://www.jeeps-offroad.com/reader-rigs/albums/album83/fullsizeflex2.sized.jpg