Fatigue reliability analysis of viscoelastic structures subjected to random loads

• A FE modeling strategy of stress responses of viscoelastic systems in frequency domain.
• Estimation of reliability of viscoelastic systems from the Sines’ global criterion.
• Provide a sense of the efficiency of the viscoelastic damping to increase the reliability level.
• Influence of uncertainties affecting the estimation of the probability of failure of systems.

This paper is devoted to the investigation of the possibility of increasing fatigue life of engineering structures subjected to multiaxial random loads by applying constrained viscoelastic layers. The rationale for such study is the fact that as the addition of viscoelastic materials provide decreased vibration amplitudes, it becomes important to quantify the increase of reliability that can be obtained. Moreover, despite the fact that many multiaxial fatigue damage criteria applicable to undamped structures exist in the literature, none of them is adapted to deal with the problem of estimation the fatigue damage in structures incorporating viscoelastic damping, since they must conveniently account for the frequency- and temperature-dependent behavior of the viscoelastic material. Due to the nature of the stress state of the considered problem, the fatigue damage is assessed by using Sine's global criterion. After presenting the theoretical aspects, the numerical fatigue damage analyses of a three-layer sandwich plate treated by passive constrained damping layer are addressed, and the main features of the methodology are discussed.