The fatigue response of additive manufactured (AMed) components is generally controlled by the defect population, and the models for assessing the fatigue response of AMed parts have to take into account the distribution of defect size and the intrinsic scatter associated to the fatigue response. In the present paper, a statistical methodology for analyzing the results of tests on AMed specimens failed due to cracks originating from defects is proposed. The procedure involves the estimation of the distribution of the fatigue life, which is considered dependent on the applied stress amplitude and on the defect size. Thereafter, all the experimental failures are shifted at a reference number of cycles to failure or stress amplitude, making it possible to compare data obtained at different stress levels or number of cycles to failure. The proposed method has been successfully validated on literature dataset, proving its effectiveness and general validity.

The research on the Very High Cycle Fatigue (VHCF) response of materials is fundamental to guarantee a safe design of structural components. Researchers develop models for the fatigue life in VHCF, aiming at assessing the stress–life relation and, accordingly, the probabilistic S–N (P‐S–N) curves. In the paper, the models for the stress–life relation in VHCF are comprehensively reviewed. The models are classified according to the approach followed for defining the stress–life dependency, that is, power law, probabilistic, fracture mechanics, or Paris law‐based approach. The number of failure modes that can be modeled, the statistical distribution for the fatigue life, and the characteristics of the estimated P‐S–N curves are also reviewed by analyzing the fitting capability of experimental datasets for each model. This review is supposed to highlight the strengths and weaknesses of the currently available models and guide the future research.

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In this work, an experimental and numerical analysis of a lattice structure for energy absorption was carried out. The goal was to identify the most influencing parameters of the unit cell on the crushing performances of the structure, thus guiding the design of energy absorbers. Two full factorial plans of compression tests on cubic specimens of carbon nylon produced by fused deposition modeling (FDM) were performed. The factors were the beam diameter and the number of unit cells. In the first factorial plan, the specimen volume is constant and the dimensions of the unit cell are varied, while the second factorial plan assumes a constant size of the unit cell and the volume changes in accordance with their number. The results showed that the specific energy absorption increases with the diameter of the beam and decreases with the size of the unit cell. Based on these results, a crash absorber for the segment C vehicle was designed and compared with the standard component of the vehicle made of steel. In addition to a mass reduction of 25%, the improved crushing performances of the lattice structure are shown by the very smooth force-displacement curve with limited peaks and valleys.