Page 3 - Prediction of Sprinting LoadsReference [1] contains graphs of pedalling force as a function of angle for a sprinting cyclist. However reaction loads elsewhere on the frame were not measured, and these are needed to model the deformation. To allow their calculation, a simple multibody analysis was performed using MSC.ADAMS.A model was created of a frame, rider, cranks, chain and rear hub. The rider was assumed not to be sitting in the saddle so was connected to the frame at the handlebars and at the pedals only. A gear ratio of 50 (chainring) to 15 (sprocket) was chosen as a typical gear that would be used in a maximal effort on level ground. The measured pedal loads were applied at the pedal locations as action-reaction forces acting between the rider and the cranks as a time history. At a realistic pedalling cadence for such an effort, 120rpm, this corresponds to a mean power output of 620W, which an elite cyclist is able to maintain for the order of one minute. The model automatically evaluated the reaction force at the connection point between the rider and the handlebars necessary to keep the rider in equilibrium, as was the load applied by chain tension on the rear axle. These loads were applied to the |
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| Figure 5 - ADAMS model for calculating load cases |