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

Hey Guys,

First things first I trust everyone had a great Christmas and a good new year's celebration.

Now that we are getting back into it I just wanted to kick of 2014 by posting this tutorial on our online simulation,

http://www.chassissim.com/blog/chass...ssissim-online

When I was in Europe and the U.S I was getting a lot of questions about this and this is your best way of getting going with ChassisSim. If you want to get going follow the instructions in the video and drop me a line at info@chassissim.com and I'll set you up with some free simulations so you can take it for a spin.

Looking forward to a great 2014 and good luck for all your competitions this year.

All the Best

Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

Just following up from last week's video I've just posted this video about how to get a model going in ChassisSim Online,

http://www.chassissim.com/blog/chass...ssissim-online

I've posted it here because a really important principal in simulation is to start simple and get complicated later. Even though ChassisSim can go into fine detail you can start simple which is what I show you in this tutorial.

Anyway some good food for thought.

All the Best

Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

I've got a few things for you this week. Firstly I have a video of one of my customers in action in the Daytona 24 hour. It's a little showy but it's good fun anyway,

http://www.chassissim.com/blog/chass...ion-at-daytona

However on a more serious note I was informed this week of the passing of Bill Mitchell, the man behind the suspension geometry software WinGeo. One of the things that we don't do particularly well in motorsports is to acknowledge when distinguished engineering figures pass away. Bill was a giant. He has left many legacies but to me his biggest legacies was his work on Force Based Roll centres which I will always be in his debt for. It is definitely worth your while chasing down his SAE Paper on the subject. Here is the link -

http://papers.sae.org/2006-01-3617/

It's really good food for thought.

Enjoy

Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

I have a real treat for you this week. ChassisSim customer Maranello Motorsport won the Bathurst 12 hour on the 9th of February 2014. Here is the link with more details,

http://www.chassissim.com/blog/chass...thurst-12-hour

There is a link to a video for the last 12 minutes of the race. Enjoy it will have you on the edge of your seat.

On a more serious note though the race engineer of that car is my Australian Dealer. We had a really good debrief about what happened at the event and how ChassisSim was used. Stand by for some really good tutorials that will spin off from this. I'll get to these when I can I'm just hammered on a few projects right now.

Enjoy

Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

I just posted the latest episode of Dan's Vehicle Dynamics corner,

http://www.chassissim.com/blog/chass...ometers-part-2

It's a follow on from a tutorial I did on evaluating racecar stability using accelerometers. It has a correction to the first tutorial I did. However more importantly it contains a much improved technique that you'll get a lot out of. I also did a Racecar Engineering article about this as well.

Enjoy and have fun trying things out.

All the Best

Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

We have just released ChassisSim v3.24. The details can be found here,

http://www.chassissim.com/blog/chass...issim-tutorial

One of the things that we have done with this release is that we have enclosed a tool called the ChassisSim Tutorial. What it does is it takes you step by step through everything you need to do to get going with ChassisSim. It's designed to get you through the beginner hump.

Enjoy


Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

I've got a real treat for you today. Remember a couple of weeks a go I mentioned one of my customers, Maranello motorsport won the Bathurst 12 hour. Here is one of the tools they used,

http://www.chassissim.com/blog/chass...d-temperatures

This is a tutorial about determining hot tire pressures from a cold start condition using the ChassisSim track replay feature. You'll get a lot out of this.

Enjoy!

Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

I'm bringing up a link to an older post that I put up over 18 months ago. It's about how to create a tyre model from nothing using ChassisSim,

http://www.chassissim.com/blog/chass...-in-the-blanks

Over the last couple of weeks I've had a lot of questions about tyre modelling so this post is particular relevant. What you have in this post is a complete battle plan to how to do tyre modelling from race data so you have a tyre model you can use in anger.

Enjoy

Danny Nowlan
Director
ChassisSim Technologies

Danny,

I have been planning to buy your book - it's the next on my list now that I recently got Seger's 2nd Edition Data Aq book.
Jorge quotes you on a tire modeling technique and I have a question about the equation he lists. You may explain this better in your book (I couldn't find it in the first chapter preview) but I can't make sense of it as given.

~~~

To find a first approximation Fy vs Fz relationship from tire data, we use a 2nd order relationship (linear decrease in friction coefficient) that can be written as

Fy_max = a1*Fz^2+a2*Fz (called 'D' c.f. Pacejka '89 etc.) (1)

or you give it as

Fy_max = ka(1-kb*Fz)*Fz = (-ka*kb)*Fz^2+ka*Fz (2)

this form being convenient since

Lp = 1/(2*kb) -> kb = 1/(2*Lp) where Lp is the 'load at which the tire peaks' (3)

I follow this so far - does it seem correct?

~~~

In the book, it seems that the approximation is that Lp is approximately the maximum normal load on a tire after sufficient track data has been gathered. We can then directly solve for kb.

This is fair for some tires I think. Do I understand this correctly?

~~~

Here is where I am confused: the next section reads (pp 414-415):

"Equations 15.20 and 15.21 estimate the total lateral tire forces ... by applying a force equilibrium around the ... axles." [Italics mine]

The equation listed is:
Fn_LF + Fn_RF = ka * ( (1-kb*Fn_LF)*Fn_LF + (1-kb*Fn_RF)*Fn_RF ) (4)

First, this sentence (Seger's wording I suppose?) is odd because to my knowledge only moments are in equilibrium around anything - and I suppose this implies Static equilibrium too though not stated.

Anyway, I cannot come up with the above equation from a FBD or any train of thought thus far. I think it could be modified to include the relevant distances to the CG as follows (assuming a right-hand turn):

(Fn_LF - Fn_RF)*(t/2) = ka * ( (1-kb*Fn_LF)*Fn_LF + (1-kb*Fn_RF)*Fn_RF )*(h) (5)

Does this new formulation seem correct or was the original right? If so, what am I missing?
Sorry if this is not your concept - though you are quoted as being the source for the idea maybe you know what I miss?

notes:
a2 = initial coefficient of friction (1/1)
ka = 'initial coefficient of friction' (1/1)
a1 = load saturation parameter (<0) (1/N)
kb = 'drop off of coefficient with load' (>0) (1/N)
Fz = load on the tire (N)
Fn_LF = load on the left front (outside) tire (N)
Fn_RF = load on the right front (inside) tire (N)
t = trackwidth (m)
h = CG height above the ground (m)


Thank you!

Goost,

My friend this is an excellent question and my apologies for the late reply. I have been hammered on a lot of projects.

The key that you are missing here is when you do this force balance you do it based on the weight distribution of each axle. Consequently it should read something like this,

wdf*mt*ay = ka * ( (1-kb*Fn_LF)*Fn_LF + (1-kb*Fn_RF)*Fn_RF )

Where,

wdf = weight distribution at the front
mt = total mass of the vehicle in kg
ay = lateral acceleration in m/s^2

To fill in the blanks a bit the following will help,

http://www.chassissim.com/blog/chass...s-from-nothing

This takes up where Jorge left of. Also when you are ready to buy the dynamics of the race car shot me an email to info@chassissim.com

Also one other thing I'll say to you and anyone reading this. Jorge Segers is a good friend of mine and one of the most switched on data and race engineers I know. Pay very close attention to his data logging book. You would be crazy not to have it.

All the Best


Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

Just on another note for any of your familiar with the Engineering software package Altair we have just joined forces,

http://www.chassissim.com/blog/chass...rtner-alliance

Just for everyone's reference, However pay attention to that post above. It was a very good question.

All the Best

Danny Nowlan
Director
ChassisSim Technologies

Danny,

Thank you; the 'tires from nothing' paper was exactly what I was looking for and your own explanation clears it up a lot.
Especially tying it back to the neutral steer channel / equilibrium concept.
I will probably be contacting you about your book soon!

Austin,

No worries my friend. Glad it helped.

All the Best

Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

I've been working with a few of my customers this week and a recurring theme that has come up is how do you employ simulation techniques. The following should help,

http://www.chassissim.com/blog/chass...on-as-a-weapon

It's one of my racecar articles about how to use racecar simulation as a weapon.

Enjoy

Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

Just a few housekeeping things. A few of you have been asking about getting started with the online simulation. This should help,

http://www.chassissim.com/blog/chass...issim-tutorial

Also just giving everyone the heads up the ChassisSim/Altair Webinar is on the 17th of April 2014. You can find more details here,

http://www.altair.com/(S(2e5lqjqqhqq...cation_id=3294

All the Best

Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

Quite a few things going on this week. Let me break it down for you 1 by 1,

1) We are about to launch the ChassisSim newsletter. It will keep you up to date on things with race car simulation and vehicle dynamics. It's also a really good to review some older tutorials and Dan's vehicle dynamics corner episodes that have dropped of the radar screen. Anyway the first one is heading out next week. If you want to subscribe here is the link,

https://confirmsubscription.com/h/r/41758C420BC5FEAA

2) I've just posted the latest video tutorial on the blog. It's about one of the key things to race car simulation. It blows me away how overlooked this gets. Any way here is the link,

http://www.chassissim.com/blog/chass...car-simulation

3) Lastly a reminder about the Altair webinar which is next Thursday. The link is above.

All the Best

Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

Just a reminder that tonight I'm giving a Webinar about how ChassisSim fits into the Altair alliance. It will be a good overview of ChassisSim. Here is the link,

http://www.chassissim.com/blog/chass...-in-april-2014

Also keep tuned next week. I have something special planned for everyone.

Hopefully I'll see a few of you tonight my time.

All the Best

Danny Nowlan
Director
ChassisSim Technologies

Hi Danny,

sorry I missed the early session for the europeans and I will not be able to attend the late one... Do you know if there will be a recording of the webinar?

Btw. I'm working at Altair in Germany ;-)

Cheers, Lutz

Lutz,

No worries my friend and sorry for the late reply. There should be a link on the Altair website where you can view a recording of the webinar. If it hasn't been put up already I'll chase down the link for you.

All the Best

Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

Today you guys are in for a real treat. This is the latest episode of Dan's Vehicle Dynamics corner where I talk about how to use ChassisSim in the race car design process,

http://www.chassissim.com/blog/chass...ign-a-race-car

If truth be told what I've just shared with you here is the tip of the iceberg. I just got of the phone with a customer and they are using ChassisSim in the design process of their race car. There using it in a way I wouldn't have thought of in a million years. This is what you have got at your fingertips.

Enjoy this is a good one.

All the Best

Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

This is what happens when you use simulation properly,

http://www.chassissim.com/blog/chass...ne-in-the-elms

A very recent ChassisSim user just took out the opening round of the European LeMans Series.

Enjoy

All the Best

Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

I was dealing with a few FSAE students as well as veteran engineers this week. A few things came to light and the following might be useful,

http://www.chassissim.com/blog/chass...d-calculations

It's one of my old racecar articles about the importance of doing hand calculations. I beg of each and everyone of you who views this post this week. Download the article, read it cover to cover and practice it. Hand calculations are the basis of engineering. It tells you what to look for and it builds up your instincts. It's also the ultimate BS detector. Unfortunately it is a dying art.

Enjoy guys.

All the Best

Danny Nowlan
Director
ChassisSim Technologies

This back to basics was much needed, thanks Danny!

Hey Guys,

First things first - Harry you are very welcome. I'm glad you got a lot out of it because this is a skill that every practising engineer needs to master.

On another note the second ChassisSim newsletter is going out tomorrow. If you haven't already subscribed here is the link,

https://confirmsubscription.com/h/r/41758C420BC5FEAA

All the Best

Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

I've just been getting a lot of questions over the last couple of weeks about circuit modelling. In particularly getting started and refining the results. The following should be a great help,

http://www.chassissim.com/blog/chass...ips-and-tricks

All the Best

Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

On the the 4th of June 2014 we ran a joint webinar with Altair about vehicle simulation. We discussed tyre modelling and Altair discussed their Motion Solve software using the F-tire plugin. Here's the link for the recording,

http://www.chassissim.com/blog/chass...lation-webinar

I certainly got a lot out of it and I reckon you'll get something out of it too.

Enjoy

Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

Sorry for the lack of content recently. I was in Europe speaking at a conference and chasing up a few loose ends.

I'll be speaking about what I got up to in Europe later. However just taking the pulse of the forum it looks as though the whole theme of tyre test rig results and quantifying tyre performance has raised it's head. The link below is an oldie but a goodie. This is the game plan from deriving tyre models from race data,

http://www.chassissim.com/blog/chass...-in-the-blanks

Many senior members of the ChassisSim community use this as their go to reference when they are faced with a tyre they have never seen before and have achieved good repeatable results for their vehicle simulations. Given the current discussions I have seen I reckon everyone will get a lot out of this. It's long but bare with it. The results are worth it.

All the Best

Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

Sorry for being off the radar screen. I've been fighting of the flu that has been circulating my part of the world.

A couple of big ticket items that are coming up.

Firstly Altair and ChassisSim are running a ChassisSim training session on Tuesday the 29th of July 2014. You can find more information here,

http://www.chassissim.com/blog/chass...nted-by-altair

Secondly and the big news is the ChassisSim simulation bootcamp is on for 2014. It will be hosted in Cologne Germany on Wednesday the 12th of November 2014. More details can be found here,

http://www.chassissim.com/blog/chass...or-nov-12-2014

These are going to be great hands on opportunities to learn about ChassisSim. In particular the bootcamp always books out so book in early to avoid disappointment.

Enjoy Guys

Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

Usually in this forum I share tidbits of vehicle dynamics knowledge. However I know many of you reading this forum are young engineers. A good friend of mine sent me this,

http://www.goodreads.com/author/quot...man_G_Rickover

Admiral Hyman G Rickover is acknowledged as the father of the US Nuclear Navy. Regardless of what you think of nuclear power and the military as all of you work through your designs and projects, and as you move on to your professional lives you'll be responsible for projects of all shapes and sizes. I trust the following will give you some good food for thought.

All the Best

Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

Just to give our North American friends the heads up ChassisSim is exhibiting at PRI,

http://www.chassissim.com/blog/chass...at-pri-in-2014

Also we are running the Lap Time Simulation 101 Seminar at PRI as well. In addition to covering the basics of lap time simulation we have some special things planned. However I'll keep you informed closer to the date.

Anyway for those of you based in North America I'm looking forward to seeing you all there.

All the Best

Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

Just a reminder about our face to face seminars at the end of the year,

http://www.chassissim.com/blog/chass...inars-for-2014

This is a great opportunity to get up to speed face to face with ChassisSim. Both the bootcamp and Lap Time Simulation 101 will cover some great stuff about how to get going with simulation and how to get the most out of it.

Also we are working on some really exciting long term stuff. However I'll bring you up to speed on that another time.

All the Best

Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

Just a couple of things,

Firstly I had a question during the week about the Lap Time Simulation 101 seminars in Indianapolis at PRI. You don't need to register for these seminars. They are free. Just turn up!

Secondly this week I ran a training session for a colleague of mine about one of my latest articles in Racecar Engineering. It was about tying together damping ratios and state space analysis to specify a damping curve. Any way we filled in a lot blanks and on the back of that here is the latest episode of Dan's Vehicle Dynamics Corner that ties these two techniques together.

http://www.chassissim.com/blog/chass...acecar-damping

Enjoy

All the Best

Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

Sorry for the lack of recent activity. I have some big ticket developments coming down the pipe and that has been dominating my radar screen.

That being said I have an oldie but a goodie for you,

http://www.chassissim.com/blog/chass...s-from-nothing

It's about creating engine curves from nothing. From time to time you'll be plunged into this situation. These are some approaches and techniques I have found very helpful. I trust you can all make good use of them.

All the Best

Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

I realise the following is a year old but here is a really good taster of what is coming at the bootcamp this year and Lap Time Simulation 101 at PRI,

http://www.chassissim.com/blog/chass...ar-teaser-2013

Forgive the references to last year's seminar. For those of you in Europe register quick the bootcamp is filling up.

Enjoy Guys

All the Best

Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

I have a real treat for you today. We have been hard at work at ChassisSim developing an Electric power train module. Here is the latest episode of Dan's Vehicle Dynamics Corner that is about Electric power train basics,

http://www.chassissim.com/blog/chass...orsport-part-1

With the advent of Formula E and with the electric component of FSAE it's a future we need to consider. Anyway you should find it a really good resource.

Enjoy

Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

A couple of community service announcements.

Firstly for all of you based in the U.S a good friend of mine Jorge Segers is running one of his data logging seminars in the U.S,

http://js-engineering.webnode.nl/dat...seminars-2014/

Jorge is one of the sharpest minds in this business I've worked and personally for all you in FSAE I think you would be mad not to give this a good hard look.

Also places for the Simulation bootcamp in Europe are filling fast and Lap time simulation 101 is coming to Indy,

http://www.chassissim.com/blog/chass...inars-for-2014

If you are in Europe and you want to come to the bootcamp let me know quickly.

All the Best

Danny Nowlan
Director
ChassisSim Technologies

Hello Danny,

the electric powertrain simulation part was really interesting! I have some questions regarding the bootcamp in Germany, specifically about the agenda/topics to be discussed and registration fees for FS/FSAE teams.

Thanks,
Harry

Hey Guys,

A couple of quick updates.

Firstly Harry my apologies in the delay in getting back to you. Things in ChassisSim world have been outrageously busy. The bootcamp will cover the basics of getting going with race car simulation and then introducing you to the more advanced features of ChassisSim. We'll be covering simulation work flow, creating a car and a circuit model, creating advanced tyre and aero models and then introducing to you to advanced features like shaker rig simulation. It is a very hands on seminar so you'll be driving ChassisSim quite a bit. The nominal rate for students is Australian $150 but I can discount for larger groups. If anyone is interested shot me an email at info@chassissim.com

In other news guys we will be exhibiting at Professional Motorsport World in Germany in November of this year. You can find the details here,

http://www.chassissim.com/blog/chass...-pmw-expo-2014

We are going to be show casing a lot of the new features of ChassisSim that includes our electric power train module and something else that I'm keeping my powder dry for now. If your based in Europe it would be great to see you face to face. We are at stand 5036.

All the Best

Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

I've got some big news. The ChassisSim simulation bootcamp is going to be run in the U.S for the first time on Thursday Dec 4, 2014 at Altair HQ at Troy Michigan. The details can be found here,

http://www.chassissim.com/blog/chass...he-usa-in-2014

Technically this is an Altair event so I don't know what they will charge. However for those of you based in the U.S it's a fantastic opportunity to get up to speed with ChassisSim.

I look forward to seeing you there and if you can't make that I'll see you at PRI.

All the Best

Danny Nowlan
Director
ChassisSim Technologies

Hey Guys,

Just a quick one - ChassisSim v3.25 has just been released. Here are the details,

http://www.chassissim.com/blog/chass...-been-released

The big thing with this release is the electric power train module. Also a reminder you can see it yourself at both PMW in Germany and PRI in the USA.

All the Best

Danny Nowlan
Director
ChassisSim Technologies