SAE MINI BAJA PROJECT Suspension Design Analysis Engineering Technology 493 Mechanical Concentration Instructor: Dr. Koutsougeras Advisor: Dr. Ho-Hoon Lee Senior design project By: Ryan Schech Spring 2014

SAE MINI BAJA COMPETITION Baja SAE® consists of competitions that simulate real-world engineering design projects and their related challenges. Engineering students are tasked to design and build an off-road vehicle that will survive the severe punishment of rough terrain.

Objectives My objectives for this project is to study and analyze the methodologies taken, by former students, in the designing of the front suspension, frame, and steering designs. I will need to modify the front chassis and suspension designs in order for commercially available parts to work on the mini baja.

Constraints to consider Frame Design by Robert Goldmon

Constraints to consider Steering Design by Alfred Showers ‘Rack and Pinion Assembly’

Suspension Design Schematic diagram of the A-arm suspension design using Inventor 2012 software.

‘Shock absorber Values’ Suspension Design From the calculations derived, a suitable option for the front shock assembly is one produced by Fox Racing, the ‘Emulsion 2.0’ shock absorber. ‘Optimal Values’ Static Ride Height – 16.430 in Max Compression -- 13.550 in Range of Motion -- 2.88 in ‘Shock absorber Values’ Stroke of 6.5 in Ext/Col  19.35/12.580 (in.) 5/8 shaft MSRP $230

Suspension Design Selection of the coil over spring will be one objective. Based on the proposed design calculations, ideally I need a spring rate of about 73 lbs/in. This is not a commonly produced spring and would cost too much to purchase a custom spring. I need to modify the design of the front chassis so that the design will work with a commercially available spring rate.

Suspension design Proposed suspension design

Suspension design An example of the A-arm design

Deliverables Theoretical Part (spring semester) Research The methodologies used in designing the front suspension, frame, and steering system by former students. Using differential equations to achieve a comfortable ride at a frequency around 1 Hertz. Application Part (fall semester) Find what spring rates are commercially available Adjust the front chassis design to allocate for the obtainable spring rate. Form an equation to represent the relationship between the change in angles and lengths of the front chassis design. Write a program in C that uses this relationship to determine the values of the variables that form the chassis design. Construct a prototype of front chassis to test the results Perform a cost analysis for the suspension

Timeline Project selection and approval 3/14 Perform the ideal calculations 4/14 Compare results to what is commercially available 4/14 Provide a research report on the design methodologies 5/14 Adjust the design to suit the available spring rate. 6/14 Form an equation representing the relationship between the variables that describe the front chassis and suspension design. 8/14 Construct a program in C that determines the variables 9/14 Obtain the appropriate suspension components 10/14 Perform cost analysis of new commercially available suspension design. 11/14

Questions?