Vehicle Simulation to Drive Formula SAE Design Decisions - Steven Webb, 2012

Monash Motorsport Final Year Thesis Collection

The Final Year Thesis, is a technical engineering assignment undertaken by students of Monash University. Monash Motorsport team members often choose to conduct this assignment in conjunction with the team. 

These theses have been the cornerstone for much of the team’s success. The purpose of the team releasing the Monash Motorsport Final Year Thesis Collection is to share knowledge and foster progress in the Formula Student and Formula-SAE community.

We ask that you please do not contact the authors or supervisors directly, instead for any related questions please email info@monashmotorsport.com

Summary:

This report covers the creation of a simple program that approximates lap time and energy for Formula SAE cars. In 2010 it was decided that Monash Motorsport would do a “clean sheet” design, so the simulation was made in order to find the effect each aspect of the car has on the car's total performance. This report also shows how to correctly validate raw test data against the equations used to create the model in order to improve the accuracy and understanding of the model and to calculate suitable performance metrics for the car.

Introduction:

Formula SAE is a student design competition where university students design and build a formula style race car. There are multiple competitions throughout America, Europe, Asia and Australia with over 400 teams worldwide. The Competitions set a strict set of rules that specify car and engine limitations, as well as point allocations and scoring formulas for each event.

Monash University has been competing since the first Australian based competition, in 2000, since then they have created 13 different cars and competed in 16 competitions. They have benefited from recent successes by achieving overall victory at the Australian competition in 2009 and 2010 and an overall 3rd place position at Formula student in the U.K. in 2010. The Monash team is now looking for their first international victory and a number 1 world ranking in order to make themselves the most respected team in the world.

In order to improve their car, a large number of significant design changes will happen throughout the 2011 season, however their resources are limited. In order to allocate resources effectively to gain the most advantage, Monash wants simulations to estimate the gains of each potential design change. Whilst most simulation software used by the team is for structural or flow analysis, they are yet to successfully use software packages to simulate overall vehicle performance.

Formula SAE cars are extremely lightweight, with competitive cars weighing between 130-250kg, this creates problems when using current simulation software designed to simulate much heavier cars. Formula SAE tracks are also much more confined and with more changes in direction than the majority of racetracks so many simulation packages will struggle to accurately simulate a car around a Formula SAE track due to inaccuracies in the transient characteristics (Phersson, 2009). Another problem with using commercial vehicle simulation software for analysing FSAE cars is that Formula SAE is not a race, it is a series of competition challenges that award points for speed, fuel economy, cost, acceleration and handling.

If Monash has a vehicle simulation package that can accurately simulate the performance of their car at a Formula SAE competition, there would be incredible advantages as it would allow them to focus their time and money on areas which would benefit them most. It could also benefit them during each competition as it could potentially help them set up their competition strategy over their closest competitors.

Conclusions:

This new method of justification through simulation has already proved successful in Monash Motorsport's 2011 season. It allowed them to make a big step forward to build a truly unique car, already armed with the knowledge of what to expect in terms of performance. Conservative assumptions were made along the way and the new car has exceeded expectations.