Search:

Type: Posts; User: Tim.Wright

Search: Search took 0.01 seconds.

  1. Not if it's done before the test and as a result...

    Not if it's done before the test and as a result you didn't waste the whole morning chasing an understeer problem.

    Simulation's strength, if used correctly, is that it lets you test more...
  2. And you really think you are going to see...

    And you really think you are going to see compliance this in a pair of front/rear mounted yaw gyros?
  3. The problem with modelling compliances on a race...

    The problem with modelling compliances on a race car is that they come primarily from the gross deflection of otherwise rigid parts NOT the joints.

    Road car compliance can be fairly accurately...
  4. I think he meant it (MBS simulation) give you a...

    I think he meant it (MBS simulation) give you a better understanding on how the compliance occurs within a given suspension - not the effects on vehicle dynamics. Prior to full 3D MBS models, I'd...
  5. Hi Bill, can you elaborate a bit on this? ...

    Hi Bill, can you elaborate a bit on this?



    I'm familiar with the need to treat in phase and out-of-phase forces seperately when defining compliances (as I mentioned in a previous post) but I...
  6. The reason I brought up the case of the lookup...

    The reason I brought up the case of the lookup tables was purely to allow arbitrary suspension to be modelled in the software rather than being restricted to the built in types that you have built in...
  7. Just to share my experiences on using lookup...

    Just to share my experiences on using lookup tables in a number of vehicle simulation models.

    I use quite coarse curves to define the kinematics (max 20pts). For compliance maps I generally use...
  8. Erik, actually I'm with you on this, the amount...

    Erik, actually I'm with you on this, the amount of fudging that goes on in the world of lap simulation is depressingly mind boggling... I've seen many "validated" lapsim models running on...
  9. Yes, I agree that parameterising the curves is a...

    Yes, I agree that parameterising the curves is a better way to go, especially in the design development stage but having a tabular definition allows you have your own parameterisation. I have used...
  10. Yea, the point densities should be "reasonable"...

    Yea, the point densities should be "reasonable" but these days I don't see any problem using a 100+ element lookup table given the available computing speed we have at our disposal.

    If you...
  11. Slightly unrelated - but have you considered...

    Slightly unrelated - but have you considered adding the possibility to model the suspension using K&C lookup tables instead of (or as well as) hardpoint definitions? This way you aren't locked into a...
  12. I'd also add that any power/energy calculations...

    I'd also add that any power/energy calculations can be used, after removing the aero component, as an input to a tyre thermal model.
  13. I think that using yawrate is the right way to go...

    I think that using yawrate is the right way to go because it contains a component of sideslip velocity.

    Slightly off topic, but in my calcs for natural frequency and yaw damping ratio seem to...
  14. I'll answer point by point, but I'll start with...

    I'll answer point by point, but I'll start with your questions about my model:


    My model is a time domain bicycle model. So there is yaw inertia . The tyres are linear and there are no tyre lag...
  15. Erik, I will give a more detailed answer later...

    Erik,

    I will give a more detailed answer later when I'm back home but I agree with your points above. The MMM line was generated using the basic sum of forces and sum of moments equations (using...
  16. Thanks Bill, I will look into this when I get a...

    Thanks Bill, I will look into this when I get a few more spare minutes.

    I have done something like the local linearised method already with a thesis student at my old uni. It was not in a dynamic...
  17. I've had a look at Danny's suggestion at looking...

    I've had a look at Danny's suggestion at looking at the data in the CN-AY plane and extracting a trend from that. What I noticed immediately is that you get a completely different looking response...
  18. I intend to keep the discussion going. I'm trying...

    I intend to keep the discussion going. I'm trying to get a hold of some data that I'm allowed to share to use in the discussion.

    Tim
  19. Hi Danny, thanks a lot for the answer. I will...

    Hi Danny, thanks a lot for the answer. I will need a bit of time to digest the theoretical part...

    On the practical side, I've messed around with some track data and its looks a bit more useable...
  20. Hi Danny, You up for a discussion about the...

    Hi Danny,

    You up for a discussion about the stability index you mentioned in your video blog? Just to clarify, I'm speaking of the equation used by yourself and Milliken:
    SI = (dN/aAy)(1/mL)
    ...
  21. I follow you, and I do agree that the Mz would...

    I follow you, and I do agree that the Mz would make up a large percentage of the understeer for a neutral or near neutral car, but my argument (and I think also Danny's) is that a large percentage of...
  22. Danny, I agree regarding the drop off in...

    Danny, I agree regarding the drop off in controlability, though I would have thought that a static margin of zero is theoretically neutral steer.

    It might not be what a driver would feel or...
  23. Not sure that's right. In a steady corner, the...

    Not sure that's right. In a steady corner, the tyre resultant force is going to go through the CG isn't it?

    My understanding of the static margin is that its the distance from the CG to the...
Results 1 to 23 of 23