Learning Forum

[BradJoe]

nYeah I'm unsure how to assign it so that the reaction force, or the force acting on the plate is true to the reality of the application. Maybe I over simplified the design, but I want to be able to apply a downward force at the large hole so that the the lobe binds with the plate due to friction, and I can measure the frictional stress experienced (at different cam angles once it works). The problem seems to arise that the friction force doesn't seem to register unless I have an initial normal fore on the plate. To create this normal force I added a force on the small hole (a known spring force which exists in the real design) that acts tangent to the large hole, creating a torque about the large hole (therefore the need for the cylindrical support) and generating an initial normal force on the plate before the larger downward force is applied. However, due to the cylindrical support I cannot apply a force at the hinge anymore and need to apply it at the granite surface, which then generates confusion with a flared crack and how I should apply the load such that it acts as the reactionary load would if applied at the hinge..nI'm not sure If the initial normal force is even required or if there's a better approach, or if I should be applying supports differently to allow the hinge force to act on the cam hinge, or if my design is correct all along, kind of just looking for some guidance on this one.nSorry if this is confusing but I've been working at this for weeks and can't seem to get a design that satisifies the hand calculations, and I'm getting funny results with the frictional stress at varying cam angles.n