| Research Abstract |
The threshold of load condition from light to heavy that Burwell and Strang proposed in 1952 as a concept of the mode transition from mild to severe wear, are tried to be estimated considering isotropic and Gaussian surface, and verification by direct observation. In brief, the threshold condition is expressed as the critical pressure at which the nominal contact area is wholly covered with the yielding area. This critical pressure has been calculated using stochastic rough surface contact theory and Johnson's Elastic Plastic Indentation model with Chang-Etsion's analysis. Individual summit of rough asperity has been assumed to be a sphericity and all of them to have the same radius. Analysis has been developed the effect of slip on rough surface contact. The contact is regarded as 2D and is assumed as that between rough surface and plane to apply the slip line field theory.
Micro-sliding mechanism are designed for the system which is able to give the normal load and shearing load to observe the realistic contact points. At the beginning the piezo-scanning stage would be planned for nano-scaled actuator, but it is difficult to decrease the shear deformation at their contact, observe the status of adhesion due to wear of the end of the 400 mm traveling by motor actuated slider.
In the experiments, normal force and tangential force are measured simultaneously. The effects of mechanical characteristics (normal pressure, shear stress, the Young's modulus, hardness and shear strength of surfaces) , geometric characteristics (surface roughness and shape) are investigated in the discussion of the wear mode. The direct observation of the realistic contact area, which mean the shape, number and area of contacted asperity is planed in the near future.
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