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I have simulated a rolling contact between bicycle and road in Motionview. The type of contact defined is volume model between the road body and the tyre body. I have provided basic joints for the motion and some forces on the saddle and handlebar. When I plotted the forces acting on the front wheel joint, i got a graph of this form. The spike in the beginning is due to the cycle dropping freely onto the road but I would like to know  why the spikes appear later on too in the force plot. I tried changing the damping coefficient values too, but the result has not much difference.

 

Bicycle_model.thumb.jpeg.a3015d06775cfbc1a5ece00ac713008c.jpeg

Bicycle model detailed

 

Force.jpeg.63fcba81b88a78a656bebfbb26dd9891.jpeg

Force plot

 

Bicycle.jpeg.27d81e0abe3f24b6440a2a332db5bdbe.jpeg

Bicycle road model

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Hi-

 

You should not be using 3D contact like this to model the tire-road interface.  There are a number of tire models accessible through MotionView.  MF-Tyre (and  as of version 2020, the Altair Fiala Tire) support motocyle and bicycle tire physics. 

 

The spikes that occur later in the simulation are likely due to the mesh of the CAD geometry.  You can make the mesh finer and finer, but it will still exist for CAD geometry as you can never completely get a perfectly smooth surface, unless you model using a sphere or cylinder with analytical contacts.  But again, if you want to model tires, you should be using the AutoTire entity, and tire data (either MF-Tyre MC, or Altair's Fiala based tire model)

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FYI, in version 2020 of Hyperworks, we have a 2-wheeler vehicle library.  While is it focused around motorcycles and scooters, it is easily adaptable to bicycles, and includes entities for referencing tire models, rather than using 3D contact which is really not a good approach for modeling tires of any kind.  We don't use 3D contact for a couple of reasons (there are probably others, but here are two big ones):

1. 3D contact is very computationally expensive relative to various tire models.

2. using 3D contact and friction does not accurately capture the physics of a tire as it is rolling over obstacles, cornering, etc.

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