Probabilistic S-N fields based on statistical distributions applied to metallic and composite materials: State of the art

Joelton Fonseca Barbosa,Shun-Peng Zhu,Rcs Freire Júnior,José Afo Correia,Abílio Mp De Jesus

doi:10.1177/1687814019870395

Abstract

Fatigue life prediction of materials can be modeled by deterministic relations, via mean or median S-N curve approximation. However, in engineering design, it is essential to consider the influence of fatigue life scatter using deterministic-stochastic methods to construct reliable S-N curves and determine safe operation regions. However, there are differences between metals and composites that must be considered when proposing reliable S-N curves, such as distinct fracture mechanisms, distinct ultimate strengths under tension and compression loading, and different cumulative fatigue damage mechanisms including low-cycle fatigue. This study aims at conducting a review of the models used to construct probabilistic S-N fields ( P-S-N fields) and demonstrate the methodologies applied to fit the P-S-N fields that are best suited to estimate fatigue life of the selected materials. Results indicate that the probabilistic Stüssi and Sendeckyj models were the most suitable for composite materials, while, for metals, only the probabilistic Stüssi model presented a good fitting of the experimental data, for all fatigue regimes.7

Highlights

Fatigue failure in materials, structural components, and structures is a factor that should be considered in engineering design to ensure safety and reliability during service life
This is even more critical in structural/ dynamic designs that use a combination of metallic materials and polymer matrix composites, or when metallic materials are replaced by composites
A state of the art on probabilistic fatigue models based on statistical distributions applied to metallic and composite materials was made

Summary

Introduction

Structural components, and structures is a factor that should be considered in engineering design to ensure safety and reliability during service life. This is even more critical in structural/ dynamic (mechanical) designs that use a combination of metallic materials and polymer matrix composites, or when metallic materials are replaced by composites. It is important to underline the significant difference between the effects of cyclic stress at the microscopic and macroscopic levels, which may explain the heterogeneous fatigue behavior of these materials. Advances in Mechanical Engineering opposite behavior to metals that do not undergo fatigue when compression is loaded.[1,2] Fatigue damage in metals generally initiates near the surface and spreads perpendicularly to the load, behavior linked to cyclic plasticity and its isotropic mechanical properties.[3,4,5,6] On the contrary, composites with a polymer matrix exhibit orthotropic mechanical properties, favoring far more complex fatigue damage than in metallic materials, including matrix cracking, delamination, fiber rupture, and failure occurring in a synergic, cumulative, and random manner.[7]

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