Análise experimental da deformação cíclica em testes de indentação instrumentada: Efeito Shakedown

Abstract

Shakedown is the name of the effect of the transition of the behavior of the material that when submitted to cyclic loading, initially responds plastically, and after a certain amount of loading cycles respond to a perfectly elastic response. This type of phenomenon occurs in situations of cyclic loading and with high contact stresses such as wheel-rail contact of a railway. A load and friction-related diagram can be used to predict material response under varying operating conditions, allowing the choice of materials and operating parameters that provide the best performance of the railway. Thus, the correct choice of operational parameters guarantees good load capacity and good braking, associated to a good life of the requested material. in addition to analyzing the influence of different mechanical properties and friction on the shakedown phenomenon in wheel-rail contact when subjected to a cyclical loading for a possible technological alternative in order to solve tribological problems in the construction of structural projects. One of the ways to analyze the plastic deformation is through instrumented hardness tests. In this work, an equipment was adapted to perform instrument hardness tests in controlled positions of a sample. Thus, the objective of this work is to reproduce the shakedown phenomenon through instrumented indentation tests in the same position.