A new free vehicle dynamics resource - Dan's Vehicle Dynamics Corner

[ChassisSim]

Hey Guys,

Just a quick one for you today. A question I often get asked, particular by a lot students and FSAE team members is where do I start with simulation and what is the work flow? The following will address this,

http://www.chassissim.com/blog/chass...etting-started

Enjoy

All the Best

Danny Nowlan
Director
ChassisSim Technologies

[ChassisSim]

Hey Guys,

I have a real treat for you today. Here's a short video on the dynamics of Front Wheel Drive,

http://www.chassissim.com/blog/chass...ing-chassissim

Enjoy

Danny Nowlan
Director
ChassisSim Technologies

[ChassisSim]

Hey Guys,

For those of you who will be in Europe in November we are running a workshop at the PMW Expo on Nov 9 2016,

http://www.chassissim.com/blog/chass...op-at-pmw-2016

Also we still have a few slots remaining for the bootcamp,

http://www.chassissim.com/blog/chass...-back-for-2016

Hurry though - the bootcamps are filling up.

All the Best

Danny Nowlan
Director
ChassisSim Technologies

[ChassisSim]

Hey Guys,

I have a real treat for you today. A couple of weeks ago I engineered a car at World Time Attack Challenge at Eastern Creek. Here is what happened,

http://www.chassissim.com/blog/chass...tion-wtac-2016

While you won't be dealing with the aero freedoms you enjoy in Time attack the following is a great case study where simulation fits in to the design and engineering process. There are also some tips here in how to approach your craft when you are not restricted by oppressive regulation. Enjoy

All the Best

Danny Nowlan
Director
ChassisSim Technologies

[Flight909]

Danny, congratulations on the good results, I enjoyed the video. Can you explain how you know the change in downforce from the dive planes? You do wind tunnel testing to learn this values?

[JT A.]

I was wondering the same thing. And then as a follow up question, if you already knew the change in downforce from adding dive planes, why was ChassisSim required to make the decision to add them to the car? You said multiple times that ChassisSim was crucial in making the decision, and you couldn't have gotten the results you did without ChassisSim. But do you really need a lap simulation to tell you that more downforce will make the car faster? Or that more front downforce will help with understeer? Maybe I'm missing something...

[ChassisSim]

Hey Guys,

First things first my apologies to both Flight909 and JT A for the very delayed reply. To say things have been busy on my end has been an understatement.

Firstly quantifying the dive plane change. The numbers for this came from all the downforce numbers we have been exposed to doing P1 and P2 sportscars. LMP2 in particular has been one of our bread and butter categories so I knew given the nature of these dive planes and the aero on this car I had a pretty fair idea of what they where going to do. When I validated it from a hand calc afterwards it was spot on. So chalk this one down to experience.

JT A - You have asked a very good question. If you knew the car needed more front grip why bother using ChassisSim? Where ChassisSim came to the party was actually quantifying the effect it was going to have. While on one level this might seem quite obvious it's quite profound. The reason it is profound is that when you get a tool like ChassisSim hooked up it will tell you what counts and what doesn't so you can focus on the stuff that makes a difference. This is why a tool like ChassisSim is so powerful.

Again my apologies for the hold up. Things have been quite busy.

All the Best

Danny Nowlan
Director
ChassisSim Technologies

[Z]

When I validated it from a hand calc afterwards it was spot on.

Huh???

It seems that "validate" is THE buzzword to drop these days, if you want to sound really professional.

Can anyone out there please explain to this old dinosaur what the word means? In an engineering context?

I note that when I go to the local mega-mall I can have my parking docket "validated" by one of the spotty-faced shop assistants. Gives me an extra hour of free parking. So, would that be enough to convince an FS-Design-Judge that "I are a real engineer, see, 'cos I done some real engineering. Look, I got it validated!".

Or would it be better to check if the design concept is "validated" by, say, checking the horoscope in a women's magazine?

I am serious. Can someone please clarify what is an acceptable level of "validation" in the FS/FSAE arena?

A "hand calc afterwards"???

Z

[ChassisSim]

Z,

Hand calculating aero to determine a car's CLA, CDA and aero balance is one of the most basic skills a data/performance engineer needs to know. It's a consequence of a simple force balance and can be readily deduced from damper displacements and matching it to your setup. It's also something I have done to death in many racecar engineering articles.

Also for those of us who work at the coal face with race engineering and vehicle dynamics on a daily basis we have a large database to draw from of the effect of what aerodynamic devices do what. This is why the data validation in this case was a fait accompli and it was within 5%.

That being said the proof of the pudding is in the eating. See image below.

All the Best

Danny Nowlan
Director
ChassisSim Technologies

[rory.gover]

There is a difference between validation and verification. It's well understood in some areas of engineering, but not properly parsed in other areas.

https://cstools.asme.org/csconnect/F...w=yes&ID=24816