Lorenzo Romanelli , Ciro Santus , Giuseppe Macoretta , Michele Barsanti , Bernardo Disma Monelli , Ivan Senegaglia , Adrian Hugh Alexander Lutey , Hossein Rajaei , Cinzia Menapace , Matteo Benedetti
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引用次数: 0
Abstract
The aim of this study is to model the impact of surface roughness and pores on the fatigue strength of plain and V-notched specimens made of Inconel 718 under as-built and machined conditions and produced by laser powder bed fusion (LPBF). Combining fractographic analyses with the Gumbel and the exponential distribution functions, the statistical analyses of the diameters of the pores and of their distances from the external surfaces were implemented. Surface roughness scans were performed with the optical profilometer. The finite element (FE) method was used to simulate a sample of pores generated by the identified probability distributions and the surface profiles obtained with the scans. The theory of critical distances (TCD) was implemented combining the blunt and sharp V-notched specimens in the machined condition, and it was combined with the Gumbel or the generalized extreme values distributions to calculate the fatigue strength concentration factors provided by the pores and the surface roughness at 99% of probability. Finally, the proposed model was used to predict the fatigue strength of the blunt V-notched specimens in the as-built conditions and of the plain specimens in the as-built and machined conditions resulting appreciably similar to the experimental data.
期刊介绍:
Typical subjects discussed in International Journal of Fatigue address:
Novel fatigue testing and characterization methods (new kinds of fatigue tests, critical evaluation of existing methods, in situ measurement of fatigue degradation, non-contact field measurements)
Multiaxial fatigue and complex loading effects of materials and structures, exploring state-of-the-art concepts in degradation under cyclic loading
Fatigue in the very high cycle regime, including failure mode transitions from surface to subsurface, effects of surface treatment, processing, and loading conditions
Modeling (including degradation processes and related driving forces, multiscale/multi-resolution methods, computational hierarchical and concurrent methods for coupled component and material responses, novel methods for notch root analysis, fracture mechanics, damage mechanics, crack growth kinetics, life prediction and durability, and prediction of stochastic fatigue behavior reflecting microstructure and service conditions)
Models for early stages of fatigue crack formation and growth that explicitly consider microstructure and relevant materials science aspects
Understanding the influence or manufacturing and processing route on fatigue degradation, and embedding this understanding in more predictive schemes for mitigation and design against fatigue
Prognosis and damage state awareness (including sensors, monitoring, methodology, interactive control, accelerated methods, data interpretation)
Applications of technologies associated with fatigue and their implications for structural integrity and reliability. This includes issues related to design, operation and maintenance, i.e., life cycle engineering
Smart materials and structures that can sense and mitigate fatigue degradation
Fatigue of devices and structures at small scales, including effects of process route and surfaces/interfaces.