BUV DESIGN TEAM

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BUV DESIGN TEAM

• Mike Naughton
• Aaron McKibben
• Gabe Currier
• William Ortiz

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Introduction

• Task To design and build a Basic Utility Vehicle
  (BUV) prototype
• Vehicle to be used in developing countries in
  rural areas
• Use many existing components
• Bottom line Low cost High durability

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Customer Requirements

• Cost as a kit 900 (less engine)
• Payload of 1000 lbs
• Top speed of 20mph
• Range of 100 miles
• Width 4.4ft
• Ground clearance 8in
• Full safety equipment

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Performance Requirements

• Climb 10 slope at 6mph (full loaded)
• Engine dry in 3ft of water
• Brakes lock two or more wheels
• Tow 385lb trailer w/ 50lb tongue wt
• Access to brake when pushing in reverse

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Front Suspension

• Double A-arm
• Leaf/solid
• Coil/solid
• MacPherson Strut
• Transverse leaf
• None

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Best result for front suspension

• MacPherson Strut
• Has good handling and low vibration
• It is durable
• Easy integration

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Steering

• Rack and Pinion
• Go-kart
• 4 Wheeler
• Recirculating-ball

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Best result for steering

• 4 Wheeler
• Simple design
• Easy to maintain
• Low cost
• Easy to handle

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Brakes

• Mechanical Cam Brake
• Mechanical Spread Lever
• Mechanical Disc Brake
• Hydraulic Servo
• Hydraulic Simplex
• Hydraulic Disc Brake

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Best result for brakes

• Mechanical Spread Lever
• Simple design
• Torque ranging from 3500lb.in. to 74000lb.in
• Applicable to many designs
• Low cost

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Rear Suspension

• MacPherson Strut
• Double A-arm
• Swing arm
• Two leaf over solid axle
• Solid axle with trailing arm and coil over shocks
• None

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Best result for rear suspension

• Swing arm
• Low cost
• Simple design
• Load carrying

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Best result for rear suspension

• Swing arm
• Honda 4 wheeler

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Drive train

• CVT with chain
• CVT with FNR gear box
• Hydrostatic transaxle
• Manual transaxle
• Manual gear box with clutch

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Best result for drive train

• CVT with chain
• Very efficient
• Light weight
• Simple design
• Low cost

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Chassis

• Triangulated space frame
• Unit body construction
• Ladder frame

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Best result for chassis

• Triangulated space frame
• Low material cost
• Low manufacturing cost
• High strength
• Fairly simple design

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Preliminary Design
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Begin Final Design Process

• Decided on final chassis design
• Material selection
• Conducted preliminary chassis analysis by hand
• Conducted advanced chassis analysis using ANSYS
• Constructed model
• Complied all data

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Final Chassis Design Sketch
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Pro-E Drawing of Final Design
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Shear Moment Analysis

• Chassis modeled as simple beam
• External forces modeled as distributed loads
  across beam
• Reaction forces found at shock locations
• Shear force and bending moment diagrams plotted

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Shear Force Diagram
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Bending Moment Diagram
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Bending-Moments by Parts

• Simplified by 2-D analysis.
• (M/EI) diagram is drawn for each load, and the
  angle ? is obtained by adding algebraically the
  areas under the various diagrams. (EI? A1 A2
  A3)
• (M/EI) diagram is drawn for each load, the
  tangential deviation t is obtained by adding the
  first moments of these areas about a vertical
  axis. (EIt c1A1 c2A2 c3A3)

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Areas and centroids of common shapes

• When a bending-moment or (M/EI) diagram is drawn
  by parts, the various areas defined by the
  diagram consist of simple geometric shapes, such
  as rectangles, triangles, and parabolic spandrels.

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The bending-moment results
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ANSYS Analysis Steps

• Model in Pro-Engineer
• Import to ANSYS
• Add constraints
• Add loads
• Run solution
• Analyze results

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Loads and Constraints
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Maximum Stress Area
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Comparison of the two analysis

• Analytically we obtained a bending-moment of
  341.27 lbs-ft at the cargo area inner weld
  joints, considering point loads and 2-D analysis.
  
• ANSYS we obtained a stress of 3111 psi at the
  seating area weld joints, considering distributed
  loads and 3-D analysis.

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BUV Model

• Scale 1 inch 1 foot
• The model helped the group make recommendations
  for improvements.

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Recommendations

• Add 1 foot to the cargo area
• Add additional support under seating area
• Changes to front of chassis to accommodate
  steering linkages

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Questions?