4 Replies Latest reply on May 4, 2007 2:20 PM by Vince Adams

    How to analyse breaking system ?

    Designer Designer
      Hi....

      Any body have experience analyse a breaking system on a vehicle ?
      For example, breaking system on bicycle wheel.

      -DD
        • How to analyse breaking system ?
          Designer Designer
          Any ideas ?
          Hope any body can share experience on this case.

          Thank`s

          -DD
            • How to analyse breaking system ?
              Vince Adams
              What parts of this system do you have questions on? If you could narrow down your issues, I might be able to offer some suggestions.

                • How to analyse breaking system ?
                  Designer Designer
                  Dear Vince...

                  Look at image below....

                  Thank`s...

                  Regards,
                  -DD
                    • How to analyse breaking system ?
                      Vince Adams
                      Hi DD, that is possible from a couple of different ways. However, as you described it, I wonder if some calculations might not be more expedient. The big question mark will be identifying a coefficient of friction between the pad and the disk. I would expect that the coefficient will change as the system heats up due to the friction. Also, the compliance of the pad will cause the area to change as increased pressure is applied, thus changing the force applied at a given pressure.

                      I don't know how sensitive your system will be to these and other environmental variables and that's why I'd probably suggest some hand calcs. This will help you keep the "ball park" nature of the estimate clear. Once you start getting detailed analytical results, they tend to romance you into thinking they are more accurate than they really are.

                      That said, you can use a contact/friction model in Motion, spin the wheel and slowly apply clamping force to watch the wheel slow down. There is a great case study we have that shows a Motion model of a friction driven speed governer. However, you won't be able to account for the temp based changes without complex governing equations (possible in Motion but beyond my knowledge of it). You also will have to assume a rigid pad.

                      Another option is to do a nonlinear study in COSMOSWorks where pad compliance can be accounted for. However, in this case, you won't be able to spin the wheel and slow it down. You'll have to measure breakaway torque when the pad lets go.

                      Hope this helps!