The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
M. Benedetti - One of the best experts on this subject based on the ideXlab platform.
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Statistical significance of Notch Fatigue prognoses based on the strain-energy-density method: application to conventionally and additively manufactured materials
Theoretical and Applied Fracture Mechanics, 2020Co-Authors: M. Benedetti, M. Dallago, Ciro SantusAbstract:Abstract The inverse search determination of the strain-energy-density (SED) control radius R1 devised in Benedetti et al. Int J Fatigue 2019;126:306-318 and based on the knowledge of the Notch Fatigue factor estimated using an optimal V-Notch specimen geometry is here reformulated to take into account the statistical properties of the input Fatigue properties. It was found that R1 exhibits a non-symmetric probability density function that is well represented by a skew-normal distribution. The uncertainty in R1 can be attributed to the uncertainty in the inverse search procedure and to the material variability in Notch sensitivity. By applying the devised procedure to real experimental data, it was found that the former contribution is preponderant in the assessment of very sharp Notches, while the latter dictates the Fatigue strength of blunt Notches, especially in the case of intrinsically flawed materials, such as those additively manufactured.
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Notch Fatigue and crack growth resistance of ti 6al 4v eli additively manufactured via selective laser melting a critical distance approach to defect sensitivity
International Journal of Fatigue, 2019Co-Authors: M. Benedetti, Ciro SantusAbstract:Abstract This work is aimed at exploring the applicability of the theory of critical distances to the Notch Fatigue prognosis of Ti-6Al-4V ELI additively manufactured via selective laser melting. Particular attention is paid on investigating how the defectiveness influences the material critical length and the path followed by the Fatigue cracks after nucleation. Fully-reversed axial Fatigue tests are carried out on Notched specimens of different severity and macrocrack growth tests are performed to determine the crack growth threshold ΔKth. The critical distance lengths are estimated according to a critical distance inverse search procedure and compared with the value deduced from ΔKth.
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modelling the residual stress field ahead of the Notch root in shot peened v Notched samples
2016Co-Authors: M. Benedetti, Masoud Allahkarami, Jay Clarke Hanan, Vigilio Fontanari, B Winiarski, P J WithersAbstract:The knowledge of the residual stress field in the vicinity of the Notch of shot peened Fatigue specimens is of paramount importance to understand the Fatigue resistance of components carrying stress raisers and subjected to surface treatments aimed at introducing compressive residual stresses. For this purpose, residual stresses were measured along the Notch bisector using two experimental techniques, namely micro-XRD and FIB-DIC micro-slot cutting and micro-hole drilling. The measurements were used to reconstruct the residual stress field through FE analyses. The obtained results accord with both experimental techniques and indicate an increasing concentration of the longitudinal residual stress component with increasing sharpness of the Notch. The proposed approach can be very useful to estimate the Notch Fatigue resistance of shot peened component on the basis of local stress and fracture mechanics approaches.
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Notch Fatigue behaviour of shot peened high strength aluminium alloys role of the residual stress field ahead of the Notch root
2015Co-Authors: M. Benedetti, Masoud Allahkarami, Vigilio Fontanari, Jay Clarke HananAbstract:The present paper is aimed at investigating the effect of shot peening on the Fatigue behavior of Al-7075-T651 samples carrying different types of Notches. The Wohler S–N curves were determined by pulsating bending for the different experimental conditions. A different improvement of the Fatigue strength was found, i.e. a different effectiveness of the treatment for different Notch geometries: the more critical Notches received the larger beneficial effect by shot peening treatment in terms of reduction of the Notch Fatigue sensitivity and increment of the Notch Fatigue strength. The Fatigue improvements with respect to the unpeened condition were discussed accounting for the residual stress effects. The residual stress field ahead of the Notch root was evaluated by means of a numerical technique, making use of XRD measurements on the plain peened specimens. The numerical predictions were then compared with the results of XRD measurements conducted in the vicinity of the Notch root of the peened Notched samples.
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Fatigue behavior of shot peened Notched specimens effect of the residual stress field ahead of the Notch root
Procedia Engineering, 2015Co-Authors: M. Benedetti, Masoud Allahkarami, Vigilio Fontanari, B Winiarski, P J Withers, Jay Clarke HananAbstract:Abstract Shot peening strongly increases the Notch Fatigue strength of metallic components. This benefit is mainly attributed to compressive residual stresses. In this paper, we address this topic by performing bending Fatigue tests on Al-7075-T651 samples carrying Notches with different severity. Fatigue lives between 10 5 and 10 8 cycles have been explored. The residual stress field ahead of the Notch has been characterized by experimental measurements and numerical reconstruction and incorporated into the Crossland Fatigue criterion combined with critical distance theory method to predict the Fatigue resistance.
M. Bandini - One of the best experts on this subject based on the ideXlab platform.
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A simplified and fast method to predict plain and Notch Fatigue of shot peened high-strength aluminium alloys under reverse bending
Surface and Coatings Technology, 2014Co-Authors: M. Benedetti, Vigilio Fontanari, M. BandiniAbstract:Abstract A simplified and fast method to predict plain and Notch Fatigue resistance of shot peened Al-7075-T651 is presented. For this purpose, different shot peening treatments were carried out on plain and Notched samples. Reverse bending SN curves were determined for both Notched and unNotched conditions. Initial and stabilized residual stresses were measured by X-ray diffraction on plain samples. An evolution to stabilised values of the surface stresses, depending on the applied loads, was observed. Residual stresses measured on plain samples were used for predicting, by means of finite element modelling, respectively the residual stress distributions in the Notched samples and the residual stress relaxation in the vicinity of the Notch due to the application of different Fatigue loads. The results of the numerical analysis were used to validate a simplified analytical approach developed for computing residual stress relaxation and surface residual stress field both in plain and Notched samples. The predicted residual stress distribution was finally incorporated into a multiaxial Fatigue criterion. Specifically, the critical distances theory was used to predict the Fatigue resistance of Notched samples in the presence of a compressive residual stress field.
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Very high-cycle Fatigue resistance of shot peened high-strength aluminium alloys
Conference Proceedings of the Society for Experimental Mechanics Series, 2012Co-Authors: M. Benedetti, Vigilio Fontanari, M. BandiniAbstract:The present paper is aimed at investigating the effect of two shot-peening treatments on the plain and Notch Fatigue behavior of the Al-7075-T651 alloy. The Wohler S-N curves were determined by pulsating bending for the different experimental conditions exploring Fatigue lives comprised between 105 and 108 cycles. It was found that improvement in plain Fatigue resistance due to shot peening steadily declines during Fatigue life. Conversely, the reduction in Notch Fatigue sensitivity due to shot peening is more pronounced in the very-high cycle Fatigue regime. Scanning Electron Microscope (SEM) fractography revealed a tendency towards sub-surface Fatigue crack initiation. The extent of the residual stress redistribution during loading was investigated by means of X-ray Diffraction measurements.
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Notch Fatigue behaviour of shot peened high-strength aluminium alloys: Experiments and predictions using a critical distance method
International Journal of Fatigue, 2010Co-Authors: M. Benedetti, Vigilio Fontanari, Ciro Santus, M. BandiniAbstract:Abstract The present paper is aimed at investigating the effect of different shot peening treatments on the Fatigue behaviour of Al-7075-T651 samples carrying different types of Notches. The Wohler S–N curves were determined by reversed bending for the different experimental conditions. A different improvement of the Fatigue strength was found, depending on the peening intensity, and, particularly, a different effectiveness of the treatments for different Notch geometries: the more critical Notches received the larger beneficial effect by the shot peening treatment in terms of reduction of the Notch Fatigue sensitivity and increment of the Notch Fatigue strength. The Fatigue improvements with respect to the unpeened condition and the influence of the peening intensity on Fatigue were discussed accounting for the residual stress effects. The extent of the residual stress redistribution during loading was investigated by means of X-ray diffraction (XRD) measurements on plain specimens. An evolution to a stabilized value of the surface stress, depending on the applied loads, was found. Residual stress fields produced by the shot peening on the Notched specimens were evaluated by means of a numerical technique, making use of XRD measurements on the plain specimens. Moreover, the application of the Fatigue load has been modelled in order to investigate the residual stress relaxation in the vicinity of the Notch. The stabilized residual stress values have been incorporated into a multiaxial Fatigue criterion to predict the Fatigue resistance. Finally, a critical distance theory method has been used to predict the Fatigue resistance of bodies carrying stress concentrators in the presence of a compressive residual stress field.
Ciro Santus - One of the best experts on this subject based on the ideXlab platform.
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Statistical significance of Notch Fatigue prognoses based on the strain-energy-density method: application to conventionally and additively manufactured materials
Theoretical and Applied Fracture Mechanics, 2020Co-Authors: M. Benedetti, M. Dallago, Ciro SantusAbstract:Abstract The inverse search determination of the strain-energy-density (SED) control radius R1 devised in Benedetti et al. Int J Fatigue 2019;126:306-318 and based on the knowledge of the Notch Fatigue factor estimated using an optimal V-Notch specimen geometry is here reformulated to take into account the statistical properties of the input Fatigue properties. It was found that R1 exhibits a non-symmetric probability density function that is well represented by a skew-normal distribution. The uncertainty in R1 can be attributed to the uncertainty in the inverse search procedure and to the material variability in Notch sensitivity. By applying the devised procedure to real experimental data, it was found that the former contribution is preponderant in the assessment of very sharp Notches, while the latter dictates the Fatigue strength of blunt Notches, especially in the case of intrinsically flawed materials, such as those additively manufactured.
-
Notch Fatigue and crack growth resistance of ti 6al 4v eli additively manufactured via selective laser melting a critical distance approach to defect sensitivity
International Journal of Fatigue, 2019Co-Authors: M. Benedetti, Ciro SantusAbstract:Abstract This work is aimed at exploring the applicability of the theory of critical distances to the Notch Fatigue prognosis of Ti-6Al-4V ELI additively manufactured via selective laser melting. Particular attention is paid on investigating how the defectiveness influences the material critical length and the path followed by the Fatigue cracks after nucleation. Fully-reversed axial Fatigue tests are carried out on Notched specimens of different severity and macrocrack growth tests are performed to determine the crack growth threshold ΔKth. The critical distance lengths are estimated according to a critical distance inverse search procedure and compared with the value deduced from ΔKth.
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Notch Fatigue behaviour of shot peened high-strength aluminium alloys: Experiments and predictions using a critical distance method
International Journal of Fatigue, 2010Co-Authors: M. Benedetti, Vigilio Fontanari, Ciro Santus, M. BandiniAbstract:Abstract The present paper is aimed at investigating the effect of different shot peening treatments on the Fatigue behaviour of Al-7075-T651 samples carrying different types of Notches. The Wohler S–N curves were determined by reversed bending for the different experimental conditions. A different improvement of the Fatigue strength was found, depending on the peening intensity, and, particularly, a different effectiveness of the treatments for different Notch geometries: the more critical Notches received the larger beneficial effect by the shot peening treatment in terms of reduction of the Notch Fatigue sensitivity and increment of the Notch Fatigue strength. The Fatigue improvements with respect to the unpeened condition and the influence of the peening intensity on Fatigue were discussed accounting for the residual stress effects. The extent of the residual stress redistribution during loading was investigated by means of X-ray diffraction (XRD) measurements on plain specimens. An evolution to a stabilized value of the surface stress, depending on the applied loads, was found. Residual stress fields produced by the shot peening on the Notched specimens were evaluated by means of a numerical technique, making use of XRD measurements on the plain specimens. Moreover, the application of the Fatigue load has been modelled in order to investigate the residual stress relaxation in the vicinity of the Notch. The stabilized residual stress values have been incorporated into a multiaxial Fatigue criterion to predict the Fatigue resistance. Finally, a critical distance theory method has been used to predict the Fatigue resistance of bodies carrying stress concentrators in the presence of a compressive residual stress field.
Vigilio Fontanari - One of the best experts on this subject based on the ideXlab platform.
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modelling the residual stress field ahead of the Notch root in shot peened v Notched samples
2016Co-Authors: M. Benedetti, Masoud Allahkarami, Jay Clarke Hanan, Vigilio Fontanari, B Winiarski, P J WithersAbstract:The knowledge of the residual stress field in the vicinity of the Notch of shot peened Fatigue specimens is of paramount importance to understand the Fatigue resistance of components carrying stress raisers and subjected to surface treatments aimed at introducing compressive residual stresses. For this purpose, residual stresses were measured along the Notch bisector using two experimental techniques, namely micro-XRD and FIB-DIC micro-slot cutting and micro-hole drilling. The measurements were used to reconstruct the residual stress field through FE analyses. The obtained results accord with both experimental techniques and indicate an increasing concentration of the longitudinal residual stress component with increasing sharpness of the Notch. The proposed approach can be very useful to estimate the Notch Fatigue resistance of shot peened component on the basis of local stress and fracture mechanics approaches.
-
Notch Fatigue behaviour of shot peened high strength aluminium alloys role of the residual stress field ahead of the Notch root
2015Co-Authors: M. Benedetti, Masoud Allahkarami, Vigilio Fontanari, Jay Clarke HananAbstract:The present paper is aimed at investigating the effect of shot peening on the Fatigue behavior of Al-7075-T651 samples carrying different types of Notches. The Wohler S–N curves were determined by pulsating bending for the different experimental conditions. A different improvement of the Fatigue strength was found, i.e. a different effectiveness of the treatment for different Notch geometries: the more critical Notches received the larger beneficial effect by shot peening treatment in terms of reduction of the Notch Fatigue sensitivity and increment of the Notch Fatigue strength. The Fatigue improvements with respect to the unpeened condition were discussed accounting for the residual stress effects. The residual stress field ahead of the Notch root was evaluated by means of a numerical technique, making use of XRD measurements on the plain peened specimens. The numerical predictions were then compared with the results of XRD measurements conducted in the vicinity of the Notch root of the peened Notched samples.
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Fatigue behavior of shot peened Notched specimens effect of the residual stress field ahead of the Notch root
Procedia Engineering, 2015Co-Authors: M. Benedetti, Masoud Allahkarami, Vigilio Fontanari, B Winiarski, P J Withers, Jay Clarke HananAbstract:Abstract Shot peening strongly increases the Notch Fatigue strength of metallic components. This benefit is mainly attributed to compressive residual stresses. In this paper, we address this topic by performing bending Fatigue tests on Al-7075-T651 samples carrying Notches with different severity. Fatigue lives between 10 5 and 10 8 cycles have been explored. The residual stress field ahead of the Notch has been characterized by experimental measurements and numerical reconstruction and incorporated into the Crossland Fatigue criterion combined with critical distance theory method to predict the Fatigue resistance.
-
A simplified and fast method to predict plain and Notch Fatigue of shot peened high-strength aluminium alloys under reverse bending
Surface and Coatings Technology, 2014Co-Authors: M. Benedetti, Vigilio Fontanari, M. BandiniAbstract:Abstract A simplified and fast method to predict plain and Notch Fatigue resistance of shot peened Al-7075-T651 is presented. For this purpose, different shot peening treatments were carried out on plain and Notched samples. Reverse bending SN curves were determined for both Notched and unNotched conditions. Initial and stabilized residual stresses were measured by X-ray diffraction on plain samples. An evolution to stabilised values of the surface stresses, depending on the applied loads, was observed. Residual stresses measured on plain samples were used for predicting, by means of finite element modelling, respectively the residual stress distributions in the Notched samples and the residual stress relaxation in the vicinity of the Notch due to the application of different Fatigue loads. The results of the numerical analysis were used to validate a simplified analytical approach developed for computing residual stress relaxation and surface residual stress field both in plain and Notched samples. The predicted residual stress distribution was finally incorporated into a multiaxial Fatigue criterion. Specifically, the critical distances theory was used to predict the Fatigue resistance of Notched samples in the presence of a compressive residual stress field.
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Very high-cycle Fatigue resistance of shot peened high-strength aluminium alloys
Conference Proceedings of the Society for Experimental Mechanics Series, 2012Co-Authors: M. Benedetti, Vigilio Fontanari, M. BandiniAbstract:The present paper is aimed at investigating the effect of two shot-peening treatments on the plain and Notch Fatigue behavior of the Al-7075-T651 alloy. The Wohler S-N curves were determined by pulsating bending for the different experimental conditions exploring Fatigue lives comprised between 105 and 108 cycles. It was found that improvement in plain Fatigue resistance due to shot peening steadily declines during Fatigue life. Conversely, the reduction in Notch Fatigue sensitivity due to shot peening is more pronounced in the very-high cycle Fatigue regime. Scanning Electron Microscope (SEM) fractography revealed a tendency towards sub-surface Fatigue crack initiation. The extent of the residual stress redistribution during loading was investigated by means of X-ray Diffraction measurements.
Zhefeng Zhang - One of the best experts on this subject based on the ideXlab platform.
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improvement of Notch Fatigue properties of ultra high cm400 maraging steel through shot peening
Journal of Materials Research, 2017Co-Authors: Q. Q. Duan, Bin Wang, Peng Zhang, Ke Yang, Zhefeng ZhangAbstract:Shot-peened CM400 maraging steel was used to study the mechanism of enhanced Notch Fatigue properties of ultra-high strength materials. After shot peening, the specimen surface became rougher, but the transversal machining traces were reduced. The yield strength was slightly improved while the ultimate tensile strength and hardness maintained constant; as a result, the Fatigue limit was promoted by about 1.5 times. The nucleated sites of the Fatigue fracture were partly changed from the surface to subsurface/interior of the specimen. To further analyze the influencing factors of Fatigue properties, the Fatigue damage process may be resolved to two aspects: (a) Fatigue damage rate affected by shear deformation and (b) Fatigue damage tolerance controlled by the dilatation fracture process. Considering the stress state near the Notch tip, the hydrostatic stress and maximum shear stress are considered for better understanding these two aspects. It is observed that the Fatigue damage tolerance increased while the Fatigue damage rate decreased after shot peening. Therefore, the Notch Fatigue properties of CM400 maraging steels can effectively be improved.
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Notch Fatigue behavior: Metallic glass versus ultra-high strength steel.
Scientific reports, 2016Co-Authors: X.d. Wang, Q. Q. Duan, Liu Zisen, Z.w. Zhu, H.f. Zhang, Zhefeng ZhangAbstract:Studying the effect of Notch on the Fatigue behavior of structural materials is of significance for the reliability and safety designing of engineering structural components. In this work, we conducted Notch Fatigue experiments of two high-strength materials, i.e. a Ti32.8Zr30.2Ni5.3Cu9Be22.7 metallic glass (MG) and a 00Ni18Co15Mo8Ti ultra-high strength steel (CM400 UHSS), and compared their Notch Fatigue behavior. Experimental results showed that although both the strength and plasticity of the MG were much lower than those of the UHSS, the Fatigue endurance limit of the Notched MG approached to that of the Notched UHSS, and the Fatigue ratio of the Notched MG was even higher. This interesting finding can be attributed to the unique shear banding mechanism of MG. It was found that during Fatigue process abundant shear bands formed ahead of the Notch root and in the vicinity of the crack in the Notched MG, while limited plastic deformation was observed in the Notched UHSS. The present results may improve the understanding on the Fatigue mechanisms of high-strength materials and offer new strategies for structural design and engineering application of MG components with geometrical discontinuities.
