About the T type ARB

[Greg11]

Hi guys,

I am in the suspension team. Here is a question about the T-type ARB. I know how we can change the stiffness in U-type ARB. However, how can we change the stiffness of T-type ARB. I think I only understand half of the T bar working principle. It would be fantastic if somebody can explain the working principle of the T-type ARB. Thanks a lot! http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Greg11]

Hi guys,

I am in the suspension team. Here is a question about the T-type ARB. I know how we can change the stiffness in U-type ARB. However, how can we change the stiffness of T-type ARB. I think I only understand half of the T bar working principle. It would be fantastic if somebody can explain the working principle of the T-type ARB. Thanks a lot! http://fsae.com/groupee_common/emoticons/icon_smile.gif

[woodsy96]

Exactly the same way as a U-bar: by changing the pickup points or the weight of the torsion spring.

A t-bar is basically a U-bar rotated 90 degrees with one double sided "moment arm" instead of 2.

[Richard Pare]

T-bars, as well as U-bars can also use "blades" as the arms that hook to the links at one end and are anchored to the bar at the other. The blades are of rectangular cross section and tapered along their length. The rectangular cross section allows the blades to have differing stiffness values as they are rotated on their longitudinal axis.

[Wesley]

Something to consider with blades - they are nonlinear and very careful simulation and testing must be done to validate their usage.

[BrandenC]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Wesley:
Something to consider with blades - they are nonlinear and very careful simulation and testing must be done to validate their usage. </div></BLOCKQUOTE>

Most everything on suspension is non-linear. Blades are nice in that they are very adjustable. Quick calculations / FEA can get you in the ballpark for desired stiffness, testing will get you where you need to be.

[Kirby]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by BrandenC:
Most everything on suspension is non-linear. Blades are nice in that they are very adjustable. Quick calculations / FEA can get you in the ballpark for desired stiffness, testing will get you where you need to be. </div></BLOCKQUOTE>

I just did a HUGE FEA assignment on a bladed lever arm, comparing calculations provided by Roaks's, ANSYS to a physical verification model. I was surprised at the difference in numbers over the three models.

I might post it up later if I remember.

[Wesley]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by BrandenC:

Most everything on suspension is non-linear. Blades are nice in that they are very adjustable. Quick calculations / FEA can get you in the ballpark for desired stiffness, testing will get you where you need to be. </div></BLOCKQUOTE>

That's all I was saying, is be wary of simple FEA. Testing is pretty crucial from a design standpoint. They might work on the car with ballparks (being adjustable,) but you need to know why and quantify effects the method of adjustment has on stiffness and response. Simply saying "adjusting them this way makes them stiffer and the car drives better" or looser or whatever. That works for driving the car, but not for design.

[Demon Of Speed]

A T-bar anti-roll bar set up works really well with a mono-shock setup.

http://images.suite101.com/1080099_com_formulabmw.jpg