Analysis

Methods for Analysis

The vehicle analyses utilized a variety of methods to create a vehicle suited for RC Baja. One of the primary methods of analysis was the use of Mechanics of Materials to analyze the different forces that are at work on the vehicles suspension system while it is in motion and being exposed to different track stressors. Another primary method of analysis used was Dynamics. This was used to figure the forces acting on the axle to determine the best material for the part. This was important to know as if the axle could not handle the stress it would break. Statics will be utilized to measure the theoretical forces exerted on the vehicle as some of the initial requirements made for the vehicles design were used to benchmark how each part should be made and what material should be used.

Requirements

The analyses made for the vehicle associated with the RC Baja project were based off of a set of requirements which helped give the vehicle design a direction in the initial stages of development. Below this, these requirements are listed.

The RC Baja car must be operational withing a 50-foot circle from the operator’s location.
The RC Baja car must complete a full 180 degree turn within a 2-foot radius from rest.
Wheels must not take up more than 25% of total vehicle weight.
The toe of the wheel should be adjustable by 3/8th inch.
The steering mechanism must have greater than 15 degrees of freedom, both left and right, relative to center.
Suspension must be able to handle force directed to all four wheels when dropped vertically from 2 feet.
Suspension must be capable of accommodating an additional 15-pound load applied to the top of the vehicle.
Suspension & Steering systems must allow vehicle to take turns at full bore while accelerating at least 10 MPH.
Struts in suspension must be able to survive at 10-pound force directed at any one of the vehicles struts.
Struts must have a clearance of 1 inch above and below wheel well.
Deflection in both subframes must not exceed 0.125 inches in any direction.
Bolt diameters in front subframe must be large enough to resist shear force applied to a factor of safety of 1.25.
Spring Rate of front springs must be greater than 5 lb/in.
Suspension must perform perfectly vertical motion to +- 0.015 inches.
Vehicle must be less than or equal to 8 lbs in total weight.
Deflection in control arms must not exceed .05 inches.
Deflection of rear coil stand must not exceed .03 inches.
Bolt diameters in rear subframe must be large enough to resist shear force applied to a factor of safety of 1.25.

Notable Analyses

Notable Analysis 1

This analysis was important to the RC Baja vehicle development as it was vital to determining how many degrees of freedom both left and right are needed for the vehicle to make a 180 degree turn in a two-foot radius. What was determined was that the vehicle needed at least 27.51 degrees of freedom to make its turns one way for a total of at least 55.02 degrees both ways. This analysis was completed using basic Algebra and Geometry

Notable Analysis 2

This analysis was important to the RC Baja vehicle development as it was the basis with which many calculations were made from in the development process. What was found was that if the vehicle was dropped from two feet, had a Factor of Safety of 1.25 and weighed at least eight pounds, then each tire would absorb about 4.99 pounds of force. This analysis was completed using physics-based math namely equations for velocity and energy

Notable Analysis 3

This analysis was important to the RC Baja vehicle development as it determined what materials the front subframe was able to be made from. The outcome of this was found to be that either material proposed, both PLA plastic and 6061 Aluminum would be acceptable with the given requirements. This analysis was completed using statics and mechanics of materials namely Free Body Diagrams for the force analysis and Beam Deflection