Simulação de microindentação de material multicamada pelo método dos elementos finitos

Abstract

Multilayered materials are widely used to improve the tribological properties of mechanical components. One way of measuring mechanical properties of multilayered materials is by indentation testing, which despite being widely used for the determination of properties, does not allow the analysis of stress fields inside the multilayered material. Due to the nature of the problem, numerical methods such as the Finite Element Method (FEM) are very useful in the stress and strain fields analysis on coated parts. This study aimed to determine, using FEM, thicknesses of coatings that delay the appearance of cracks and delamination of a multilayered material, as well as analyze the influence of the indentation depth in the test response. The material is composed of an extern layer of Diamond-like Carbon (DLC), a nitride chromium layer (CrN) and a low carbon steel ABNT 1020 substrate. Forty nine (49) models of different thickness were simulated, with 7 thickness for each coating, according to manufacturing possibilities and planning. These thicknesses were chosen based on two objective criteria: i. Maximize the distance of the maximum shear and radial stresses from the material interfaces, into the CrN layer, and ii. Minimize the maximum radial stress within the DLC layer. To analyze the influence of indentation depth were made five simulations with different depths of indentation. The simulation used the Explicit Finite Element Method, with the software STAMPACK®.