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Asperity flattening study plays an important role in predicting the friction behavior at the interface and the surface roughness transfer during sheet metal-forming process. This paper presents a comparison of asperity flattening activities under 1-wavelength, 2-wavelength and 3-wavelength finite-element models developed based on a power spectral density (PSD) analysis of measured data on steel sheet surfaces. First, a proper asperity thickness for the modeling has been determined by the investigation of plastic strain distribution along the depth of asperity. The comparison then examines the evolution of real contact area, surface roughness, contact pressure distribution and variation of friction force at the interface between a tool and a workpiece drawn from different wavelength simplification models under various friction conditions. It is concluded that 3-wavelength model has closer results to experimental measurements and introduces less contact area and more local pressure concentrations than those from the other two models. [Copyright &y& Elsevier]

In this paper, we use a prevalent finite element analysis software, MARC, to simulate the process for a subject material undergoing equal channel angular extrusion (ECAE), as well as calculating the strain conditions. For a single ECAE pass, the transversal strain distribution in the deformed body will be analyzed to investigate the influences from channel angle, friction between die and pressed material, and curved joining channels. Simulations involving double passes of the subject material were also conducted, something that has not been previously pursued much elsewhere. [Copyright &y& Elsevier]