Issue 41

Carpinteri A. et alii, Frattura ed Integrità Strutturale, 41 (2017) 40-44; DOI: 10.3221/IGF-ESIS.41.06 40 Focused on Multiaxial Fatigue Effect of spectral cross-correlation on multiaxial fatigue damage: simulations using the critical plane approach Andrea Carpinteri, Andrea Spagnoli, Sabrina Vantadori University of Parma, Italy andrea.carpinteri@unipr.it, http://orcid.org/0000-0002-8489-6005 andrea.spagnoli@unipr.it, http://orcid.org/0000-0002-0592-7003 sabrina.vantadori@unipr.it , http://orcid.org/0000-0002-1904-9301 A BSTRACT . The present paper aims to discuss a frequency-domain multiaxial fatigue criterion based on the critical plane approach, suitable for fatigue life estimations in the presence of proportional and non-proportional random loading. The criterion consists of the following three steps: definition of the critical plane, Power Spectral Density (PSD) evaluation of an equivalent normal stress, and estimation of fatigue damage. Such a frequency-domain criterion has recently been validated by using experimental data available in the literature, related to combined proportional and non-proportional bending and torsion random loading. The comparison with such experimental data has been quite satisfactory. In order to further validate the above criterion, numerical simulations are herein performed by employing a wide group of combined bending and torsion signals. Each of such signals is described by an ergodic, stationary and Gaussian stochastic process, with zero mean value. The spectrum of each signal is assumed to be represented by a PSD function with rectangular shape. Different values of correlation degree, variance and spectral content are examined. K EYWORDS . Critical plane-based criterion; Frequency-domain criterion; Power Spectral Density. Citation: Carpinteri, A., Spagnoli, A., Vantadori, S., Effect of spectral cross- correlation on multiaxial fatigue damage: simulations using the critical plane approach, Frattura ed Integrità Strutturale, 41 (2017) 40- 44. Received: 28.02.2017 Accepted: 15.04.2017 Published: 01.07.2017 Copyright: © 2017 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION ngineering structures suffer from failure associated with fatigue, both at the stage of manufacturing and under service conditions [1]. Examples in the civil engineering field are jack-up platforms, bridges, towers and masts, for which their structural integrity is of paramount importance both to avoid huge material losses and ecological disaster and to ensure the life and health of people. Fatigue damage in structures is caused by progressive crack growth under time-varying loading [2]. A method of analysis, named time-domain analysis, is that to consider a loading time history on the structure to find the output response caused E