Análise de tensões e deformações em sólidos texturizados e revestidos

Abstract

Multilayered media are often used to enhance tribological properties in contact regions. Studies show that the presence of some patterns in the surface of the components, not only can low the friction coefficient but also can increase the lifespan of the layers. Many tribological tests prove the efficiency of the surface pattern, however, relatively few studies discuss the stress and strain fields of those materials. Since these analyses take a lot of effort and are very complex, numerical methods are very useful to help the analyses of those behaviours. This study aims to investigate the influence of the textured surfaces, coated and uncoated, in the stress and strain fields, due to a spherical indentation, using Finite Elements Method , and also the inlfuence of some geometric parameters. The patterned surface exhibits circular pockets regularly distributed in the surface with a density of 25% of the total area with two configurations, one with the ratio diameter/depth of 100/10 μm another with 200/20 μm. The solid is made of low carbon steel, coated with a chromium nitride (CrN) with 3.24 μm thickness, covered with a layer of diamond-like carbon (DLC) with 0.58 μm thickness. Several elastic-plastic finite element analysis of a sphere in normal contact with a flat, patterned and patterned and coated media were conducted in order to verify the transition of behaviour between the different scenarios. The simulations were performed with ABAQUS®, and the results are presented for the stress and deformation fields. Results shows that the pattern enhance the stress and deformation, as well create regions of stress concentration. The textured layered solid presented high values of stress with less plastic deformation in the substrate, which is protected by the layers. And the texture with the ratio diameter/depht of 200/20 μm exhibited better results, showing lower values for stress and plastic deformation when compared with the other geometry analysed.