Dimensionless description reduces the number of parameters from nine to five fourr of the five dimensionless parameters control the occurrence limit of friction-induced vibration.
To illustrate this point, Fig. 6 shows 2-finger frictional grasps on a rectangle; Fig. 6a presents an example of an optimum grasp with the forces applied at the center of its corresponding friction cone, and Fig. 6b shows a low quality grasp with the forces close to the limit of the friction cone.
For verification, a comparison of the present model in the limit of zero friction with the original (frictionless) KTGF model is carried out.
However, it is experimentally possible to determine the limiting value of friction since it is a property of the two surfaces involved.
The example most commonly used in practice (especially by bearing, polymers or gears producers) is the pV (pressure x velocity) criterion, which offers the possibility of calculating the limits for friction pairs that are working under different kinetic configurations of materials and tribological conditions.
At contact stresses below the FEM-predicted elastic plastic limit, the coefficient of friction decreased linearly with increase in contact stress, suggesting that interfacial shear is the major mechanism of friction in DLN.
Therefore, data filtering has been performed for a minority of these exceptional values based on the upper or lower limits of the friction coefficients shown in Table 1.
In the limit of extremely low friction, the microscopic motion is stick-slip, and the trajectory might be characterized by Lévy flight [12].
These results demonstrate that both PRG4 and high MW HA concentration can be limiting in achieving reduction of friction in the boundary mode at a cartilage-cartilage biointerface, and that both are necessary contributors to the cartilage boundary lubricating ability of SF.
An upper-bound value of the maximum horizontal stress (SHmax) constrained by frictional limits and the coefficient of friction (μ=0.6) is about 27.36 MPa/km.
In this paper, an attempt was made to develop process operation limit diagrams in the form of friction stir spot welding windows for obtaining good quality dissimilar Al 5086/ C10100 joints.
