Notes

Outline

BUV DESIGN TEAM Mike Naughton Aaron McKibben Gabe Currier William Ortiz

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

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

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

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

Slide 6

Best result for front suspension MacPherson Strut Has good handling and low vibration It is durable Easy integration

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

Slide 9

Best result for steering 4 Wheeler Simple design Easy to maintain Low cost Easy to handle

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

Slide 12

Best result for brakes Mechanical Spread Lever Simple design Torque ranging from 3500lb.in. to 74000lb.in Applicable to many designs Low cost

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

Slide 15

Best result for rear suspension Swing arm Low cost Simple design Load carrying

Best result for rear suspension Swing arm Honda 4 wheeler

Drive train CVT with chain CVT with FNR gear box Hydrostatic transaxle Manual transaxle Manual gear box with clutch

Slide 19

Best result for drive train CVT with chain Very efficient Light weight Simple design Low cost

Chassis Triangulated space frame Unit body construction Ladder frame

Slide 22

Best result for chassis Triangulated space frame Low material cost Low manufacturing cost High strength Fairly simple design

Preliminary Design

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

Final Chassis Design Sketch

Pro-E Drawing of Final Design

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

Shear Force Diagram

Bending Moment Diagram

Bending-Moments by Parts Simplified by 2-D analysis. (M/EI) diagram is drawn for each load, and the angle θ is obtained by adding algebraically the areas under the various diagrams. (EIθ = 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)

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.

The bending-moment results

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

Loads and Constraints

Slide 36

Maximum Stress Area

Slide 38

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.

BUV Model Scale:                    1 inch = 1 foot The model helped the group make recommendations for improvements.

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

Questions?