Design Process and Goal Design Process and Goal Setting for FSAESetting for FSAE

This presentation will discuss the importance of setting appropriate goals for the competition, and how to go about accomplishing them.

Design LevelsDesign Levels

Before discussing goals, we must establish some background about design

There are three levels of design on which the best teams operate– Level 1: Component Design– Level 2: Vehicle Integration– Level 3:Competition Package Integration

Level 1:Component DesignLevel 1:Component Design

Level 1 is designing individual components, evaluating how to make a single part better.

This can include:– Finite Element Analysis– Component choice– Stress, bending, or vibrational analysis

“Choose the right bolt”

Level 1, ExplainedLevel 1, Explained

“Choose the right bolt”– At this level, we’re looking to optimize

each component for its specific purpose. How strong does the bolt need to be?How long should the shank/ threads be?What type of retention does it require?Could it be lighter?

– Picking the bolt that meets all these criteria is effective Level 1 design.

Level 2: Vehicle IntegrationLevel 2: Vehicle Integration

Level 2 is designing how the various components will fit together into subsystems, and how the subsystems attach to the car– How do the components interface with

each other? Well?– How do we design the suspension to work

with our differential choice? – How to mount the engine for easy

service?

Level 2, ExplainedLevel 2, Explained

At this level, we’re interested in how one component can benefit others– Effective level 2 design is not merely

bolting together well-done pieces from level 1.

– Given the vehicle as a total system, how do the subsystems make the car better?

Level 2, ExampleLevel 2, Example

Objective: Maximize tire performance– The tires perform best when hot, so heat the

tires quickly– A spool differential heats up tires quickly

A spool requires lifting a wheel slightly to reduce under steer. What suspension geometry accomplishes that?

What torque curve suits the power delivery needs for that given set-up?

Good level 2 design balances all these issues

Level 3: Competition LevelLevel 3: Competition Level

Competition covers diverse parameters– “Racing” (vehicle dynamics, lap times) – “Non-racing” (cost, fuel economy)

Each parameter is allotted pointsThe winner is the team who designs

their car to maximize the opportunity for points

Level 3, ExplainedLevel 3, Explained

In order to maximize points:– Score points in all events

Dynamic events = 700/1000 pointsStatic events = 300/1000 points

– Perform better than other teams in each event

Optimize car for competition scenario

Level 3, Further ThinkingLevel 3, Further Thinking

A car with more power is faster, but likely heavier to handle the power– Benefit for acceleration (75 pts)– Benefit for straights of autocross and

endurance (~10% of 450 pts)– Detriment to fuel economy (100 pts)– Detriment to skid pad (50 pts)– Detriment to braking and cornering of

autocross and endurance (~90% of 450 pts)

Level 3, Further ThinkingLevel 3, Further Thinking

The car which has less power, but weighs less has an advantage for the majority of the point distribution

Choosing a design philosophy which maximizes the potential for points is effective level 3 design.

Purpose of GoalsPurpose of Goals

Establish team direction and focusCar is made up of thousands of

decisionsEvery decision should be made in

order to meet at least one of the goals, more is better

Setting Team GoalsSetting Team Goals

Team goals should trickle down from level 3 back to level 1

Setting Team GoalsSetting Team Goals

Max points = compete in each event– Overarching goal is to complete every

event– In order to compete in each event, the

car must be reliable. More than weight, power, suspension tuning, or any other parameter (except safety) the car must run continuously for the entire competition without failure.

Setting Team GoalsSetting Team Goals

– As seen in the power vs. weight example, more power helps a small part of the competition. Reducing weight improves performance across the board. Therefore, the strategy for lowering the car’s weight is a team goal. This goal drives vehicle parametersEngine choiceSuspension strategy

– After choosing high level strategy, the smaller pieces should fall into place

Setting Detail GoalsSetting Detail Goals

– The plan for accomplishing the higher level goals fall to the lower levelsReduce “x” or increase “y” for a given part

(physical parameters: weight, stiffness…)Reduce the compliance of the stack-up of

these partsIncrease manufacturability, reduce cost Improve adjustability or ease of assembly

Food ExampleFood Example

Cooking a meal can be a metaphor for designing the car for the competition. In cooking a meal, a chef has ingredients and methods to prepare them. He can start with fine steak and quality potatoes to prepare a meal. With a goal of creating a wholesome plate of meat & potatoes, the chef has direction and a plan for maximizing the ingredients available. A trip to the grill for a sear on the steak and a mixer to mash the potatoes will deliver a successful final product.

Food Example, continuedFood Example, continued

However, if the chef lacks direction, and instead mashes the steak and sears the potatoes, the meal is ruined. The quality of the individual ingredients doesn’t matter if they are not prepared and assembled well.

But how does this relate to a race car?

Food Example, explainedFood Example, explained

It doesn’t particularly matter that you made steak and potatoes. It doesn’t even matter much if the steak is a bit overdone and the mashed potatoes have a few lumps. What does matter is why you chose to make steak and potatoes (as opposed to say, chocolate cake) and if your strategy to prepare the meal is well founded and works. Why is steak and potatoes the best dish for the competition? Why not cake?

Food Example, explainedFood Example, explained

The team whose car best takes advantage of the available ingredients, and makes the most of them has the best chance to win. The team who sets their goals appropriately, and then accomplishes them, and understands why the processes they used are the correct ones will be the most successful in competition.

ConclusionConclusion

In order to design a successful race car for the Formula SAE competition, the team should evaluate what dish they think would best suit the parameters of the competition as defined by the rules, and set that as the top level goal. Then they should appropriately design their ingredients to work in harmony to maximize their potential, and make the dish more suited to the palate of competition than all the other competitors.