ADAMS Modelling

[Chris Boon]

Hello People,
I was interested to know how many people use ADAMS to model their car in scenarios such as skidpad and with how much success? Currently I am using a model someone made of our last year's vehicle and it models a single-lane change fine but will not allow me to model a skidpad simulation as it fails in the static Equilibrium analysis. Would anyone have any know how into what common problems occur with people using ADAMS?

Cheers Chris

Suspension
UQ Racing, Australia

[Chris Boon]

Hello People,
I was interested to know how many people use ADAMS to model their car in scenarios such as skidpad and with how much success? Currently I am using a model someone made of our last year's vehicle and it models a single-lane change fine but will not allow me to model a skidpad simulation as it fails in the static Equilibrium analysis. Would anyone have any know how into what common problems occur with people using ADAMS?

Cheers Chris

Suspension
UQ Racing, Australia

[Badi]

I'm an FSAE alum who currently works for a Big 3 auto manufacturer performing ADAMS simulation full time. Even with all the resources/expertise available here we often have difficulty accurately simulating hi-g driving events. Before spending a great deal of time on ADAMS I would I ask myself some basic questions:

1. What are the specific vehicle performance areas you want to optimize with your model: Max Lateral accel, Straight line accel,...What is the procedure you will use to optimize this performance?

2. How much time do you want to spend on this? It can take weeks of full-time work to troubleshoot/correlate a model.

3. How confident are you in the input data to your model. Have you accurately modeled ALL the suspension & steering component compliances? What about local&global structural compliances? Have you measured the steady-state and transient properties of your tire at race temperature. Have you measured your damper properties at race temperature? If the answer is no to any of these questions, Your results will be inaccurate!!

4. Could you arrive at the same answer with a simpler analysis tool. In industry we try to use the simplest tool to get the job done. Have you looked into CarSim software for dynamic simulation? this software is MUCH easier to use and probably more insightful for your purpose.

5. What is your overall goal? If you want to learn about ADAMS, this is a great way. If you want to improve your car's performance, ADAMS is probably not the best method given your time and resource constraints

[flavorPacket]

Badi, I think you are absolutely correct.

After about 6 months of straight pain, I decided that doing a full vehicle in A/car for FSAE is overkill. Use Carsim/whatever to get an idea of what's going on, and leave A/car to companies with rooms full of people working full-time on it.

That being said, I think it's nice to use ADAMS for front and rear assemblies and maybe a 'light' vehicle (ie front and rear assemblies plus wheels and a chassis). You can certainly get a lot out of those models if you know the limitations/expectations of the software.

I'd personally stay away from doing driving events because ADAMS requires you to have so much data beforehand.

[GSpeedR]

Dammit, is that Kraft?

[John_Burford]

I will agree with the general I will agree with the general sentiment that Adams/Car is a poor tool for Formula SAE. The A/Car structure is designed around building libraries of component properties. That's great for a major passenger car manufacturer. This doesn't help FSAE teams who are trying to build prototypes.

On the other hand, Multi-Body Dynamics is a rewarding a lucrative field. So even if Adams is challenging to use for FSAE, I would not write off MBD analysis altogether. There are some other options.

Altair's MotionView would allow you to build up to a full vehicle model in steps. You can start with geometry point locations of a half car model. This gives you your basic kinematics data; with not much more work than using Mitchell's software. The advantage is the half car model can be added to a full car model later. Later you can add mass, inertia, spring, and compliance data. Also MotionView has an export function to generate the K & C data to import into CarSim (if you want to go that route). I personally find MotionView easier to learn than Adams as well.

Which ever open architecture Multi-Body Dynamics tool you choose to learn (Adams, MotionView, LMS VirtualLab.motion, Abaqus, SimPak, or SimuLink), it will be a good investment for your future. MBD people with hands design and fabrication experience are hard to find.

John Burford

[nkapeta]

Hello all!
I'm currently using Adams/Car to make a model of our past car and I found some critical difficulties,that made me look for other softwares.. I'm wondering,at which level can someone model a car in CarSim?Could I somehow import the correct geometry data from our car?Do I also need SuspSim for that puprose?
Best regards!
Alex