[103] Fatigue damage estimation under random vibration load: analytical model and experimental validation
L Campello1,2, R Serra1, R Sesana2 and C Delprete2 1INSA Centre Val de Loire, France 2Politecnico di Torino, Italy
Many mechanical components are subjected to vibrations, generating in the material a stress history related to vibration amplitude and frequency. Vibration can lead to fatigue failure, as a result of accumulated damage. An adequate design of components and systems allows the damage of the components subject to vibrations to be estimated and its life to be predicted. Most of the vibrations are non-deterministic vibrations, so-called random vibrations. Non-deterministic excitations are a type of oscillation in which behaviour is non-predictable and non-repeatable. Many methods of predicting the vibration response of mechanical and structural systems to random vibrations are presented in technical literature. The fatigue damage assessment can be approached in both the time and frequency domains. In the time domain, rainflow cycle counting and the linear damage rule are used; in the frequency domain several methods are available. The approach in the frequency domain carries a significant benefit in terms of calculation time and a more efficient assessment of the random process. In the frequency domain the load is described by the power spectral density (PSD) function, which represents the distribution of power into frequency components composing the time signal. However, the damage estimation results are approximated and, for a reliable estimation, large and expensive testing campaigns are required. Damage and life simulation models are a helpful tool nowadays. The purpose of this work is to create a finite element method (FEM) model, the goal of which is to predict, with a reliable accuracy, the fatigue damage and the residual useful life of an AISI 304 specimen loaded with a random vibration.
Keywords: random vibrations, fatigue damage, virtual test.
Keywords: random vibrations, fatigue damage, virtual test.
