Influence of overloads on the fatigue crack growth in nodular cast iron: experiments and numerical simulation

Mottitschka, T.; Pusch, G.; Biermann, Horst; Zybell, Lutz; Kuna, Meinhard

doi:10.1016/j.proeng.2010.03.168

Cited by 14 publications

(14 citation statements)

References 5 publications

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“…Considering the value of the material yield strength σYS listed in Table 3, the maximum theoretical fracture toughness that can be estimated using this C(T) sample geometry is ≈32 MPa m 0.5 , which is comparable with KIc values reported in the technical literature [56,57] for this DCI class. Figure 10a,b shows the load versus crack mouth opening displacement recorded for specimen 1 and 2, respectively.…”

Section: Fracture Toughnesssupporting

confidence: 77%

“…It can be noted that Equation (3) Figure 7a compares the curves obtained by fitting Equation (3) to the present experimental data and those measured by Mottitschka et al [56] on an EN-GJS-400 DCI type with very similar chemical composition but obtained under fast solidification conditions leading to a mean graphite diameter of about 10 µm and therefore denoted as G10. Unexpectedly, it can be noted that the present material displays a noticeable higher resistance to fatigue crack growth, especially in the near-threshold regime.…”

Section: Fatigue Crack Growth Curvessupporting

confidence: 70%

“…Clearly, this is not a true stress intensity factor, as prescriptions and procedures set by ASTM-1820 are not met. Anyway, if the data illustrated in Figure 6 are elaborated in the same way, a value of K Ic ≈ 45 MPa m 0.5 is obtained, thus higher than the values reported by [47,56].…”

Section: Fracture Toughnessmentioning

confidence: 62%

“…Therefore, the second phase of crack growth testing performed under constant force amplitude is conducted only after the crack extension has overcome the minimum value of 4 mm. To this regard, it can be noted that Zambrano et al [55] used C(T) samples with crack sizes less than 2 mm and reported very low fatigue crack growth resistance in comparison with other papers dealing with similar DCI [47,56,57]. …”

Section: Fatigue Crack Growth Curvesmentioning

confidence: 95%

“…On the other hand, unfavorable microstructural conditions caused by the long solidification time could have a negative effect on the fracture toughness, even though to a lesser extent than that observed in Section 3.2 on tensile and fatigue strength. Hübner et al [47] and Mottitschka et al [56] did not perform true fracture mechanics tests but inferred the material fracture toughness K Ic from fatigue crack growth tests and calculated it as K Ic = ∆K c /(1 − R), where ∆K c is the asymptotic value of the stress intensity range at which the crack growth rate tends to infinite. Clearly, this is not a true stress intensity factor, as prescriptions and procedures set by ASTM-1820 are not met.…”

Section: Fracture Toughnessmentioning

confidence: 99%

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Fatigue and Fracture Resistance of Heavy-Section Ferritic Ductile Cast Iron

Benedetti

Torresani

Fontanari

et al. 2017

Metals

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Abstract:In this paper, we explore the effect of a long solidification time (12 h) on the mechanical properties of an EN-GJS-400-type ferritic ductile cast iron (DCI). For this purpose, static tensile, rotating bending fatigue, fatigue crack growth and fracture toughness tests are carried out on specimens extracted from the same casting. The obtained results are compared with those of similar materials published in the technical literature. Moreover, the discussion is complemented with metallurgical and fractographic analyses. It has been found that the long solidification time, representative of conditions arising in heavy-section castings, leads to an overgrowth of the graphite nodules and a partial degeneration into chunky graphite. With respect to minimum values prescribed for thick-walled (t > 60 mm) EN-GJS-400-15, the reduction in tensile strength and total elongation is equal to 20% and 75%, respectively. The rotating bending fatigue limit is reduced by 30% with respect to the standard EN-1563, reporting the results of fatigue tests employing laboratory samples extracted from thin-walled castings. Conversely, the resistance to fatigue crack growth is even superior and the fracture toughness comparable to that of conventional DCI.

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Section: Fracture Toughnesssupporting

confidence: 77%

Section: Fatigue Crack Growth Curvessupporting

confidence: 70%

Section: Fracture Toughnessmentioning

confidence: 62%

Section: Fatigue Crack Growth Curvesmentioning

confidence: 95%

Section: Fracture Toughnessmentioning

confidence: 99%

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Fatigue and Fracture Resistance of Heavy-Section Ferritic Ductile Cast Iron

Benedetti

Torresani

Fontanari

et al. 2017

Metals

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Microstructure based fatigue analysis of cast components under variable amplitude loading

Eufinger

Heinrietz

Bruder

et al. 2011

Materialwissenschaft Werkst

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Reliable numerical fatigue life analyses are becoming increasingly important given the need to reduce the time and costs for product development and the need to evaluate large and single components. Stress-based approaches as well as the local strain approach and its fracture mechanics based extension (PJ model) are in use for that. Both the local strain approach and the PJ model require the supply of pure material data. This requirement for input data that are not component-specific makes such approaches interesting for widespread application. The accuracy of numerical fatigue life analyses is an essential criterion for the acceptance and the spread in industrial application. In the local strain approach, accuracy is determined on one hand by the transferability of material data for the fatigue life analysis of components and on the other by the damage accumulation rule. In this paper, the local strain approach and the PJ model are used to analyse fatigue life under bo th constant and variable amplitude loading. These analyses are based on the experimental results obtained from tests of a commercial vehicle component made of nodular cast iron EN-GJS-400-15. Aspects of transferability and damage accumulation are considered. Results obtained from using an elastic-plastic fracture mechanics based approach to estimate a P SWT-N curve, taken into account the inhomogeneities in the microstructure of the cast iron, are also presented

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