Probabilistic fatigue S-N curves derivation for notched components

Smolnicki

et al. 2019

Metals

The paper summarises an experimental study on the fatigue crack propagation and cracks paths in ancient steel—19th-century puddle iron from the Eiffel bridge. The tests were performed with the load R-ratio equal to 0.05 and 0.5. All tests were performed under different notch inclinations (mode I + II). The fatigue crack growth rate in the tested material is significantly higher than its “modern” equivalent—low carbon mild steel. The crack closure phenomenon occurs in specimens during the process of crack growth. Understanding this aspect is crucial for the examination of a stress R-ratio influence on kinetic fatigue fracture diagram (KFFD) description. Both the experimental and numerical approach, using the HP VEE environment, has been applied to the crack closure as well as the crack opening forces’ estimation. These analyses are based on the deformation of the hysteresis loop. The algorithm that was implemented in the numerical environment is promising when it comes to describing the kinetics of fatigue crack growth (taking into consideration the crack closure effect) in old metallic materials.

Section: Introductionmentioning

confidence: 99%

Fatigue Crack Growth Rate of the Long Term Operated Puddle Iron from the Eiffel Bridge

Lesiuk

Smolnicki

et al. 2019

Metals

“…However, the probabilistic fatigue model proposed by Castillo and Ferna´ndez-Canteli 48 presents better results when only the high-cycle fatigue data are considered according to the previous studies. 22,35,47,52,[68][69][70][71]82 It is important to refer that all models were identified using the complete set of experimental fatigue data.…”

Section: Rmsementioning

confidence: 99%

“…[40][41][42][43][44][45] Correia et al 46 have used in its research work this ASTM standard with the purpose of generating the design curves for fatigue crack growth (FCG) rates applied to old steel bridges materials, demonstrating the applicability of this methodology to other laws. Raposo et al 47 presented a methodology to generate P-S-N curves applied to the structural and mechanical components, based on the FCG modeling as a process of successive crack re-initiations, using local fatigue damage parameters (e.g. strain, Smith-Watson-Topper (SWT), etc.).…”

Section: Introductionmentioning

confidence: 99%

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

Barbosa

Advances in Mechanical Engineering

Júnior

et al. 2019

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

“…Other authors, such as, Correia et al [8][9][10][11][12][13][14] and Hafezi et al [15] used the strain and SWT fatigue local relations [16], based on UniGrow model [4,6,7] to predict the fatigue crack propagation using the numerical analysis to obtain residual stresses distribution. Correia et al [9,17,18] proposed a procedure to derive probabilistic S-N-R fields for notched structural details or mechanical components, which is based on the UniGrow model and numerical analysis aiming at computing the elastoplastic stresses and strains at process zone ahead the crack tip. Alternatively, analytical methods such as the ones proposed by Neuber [19] and Moftakhar et al [20] may be applied to perform the elastoplastic analysis taking into account the elastic stress/strain fields computed around the crack tip, using available Linear Elastic Fracture Mechanics solutions [4,20,21].…”

Section: Introductionmentioning

confidence: 99%

Fatigue crack propagation prediction of a pressure vessel mild steel based on a strain energy density model

Huffman

Ferreira

Frattura Ed Integrità Strutturale

et al. 2017

Self Cite

Fatigue crack growth (FCG) rates have traditionally been formulated from fracture mechanics, whereas fatigue crack initiation has been empirically described using stress-life or strain-life methods. More recently, there has been efforts towards the use of the local stress-strain and similitude concepts to formulate fatigue crack growth rates. A new model has been developed which derives stress-life, strain-life and fatigue crack growth rates from strain energy density concepts. This new model has the advantage to predict an intrinsic stress ratio effect of the form σ ar =(σ amp ) γ ·(σ max ) (1-γ) , which is Fatigue crack propagation prediction of a pressure vessel mild steel based on a strain energy density model, Frattura ed Integrità Strutturale, 42 (2017) 74-84.