Preview

Industrial laboratory. Diagnostics of materials

Advanced search

STUDY OF THE DURATION OF THE FATIGUE CRACK GROWTH IN STEELS DEPENDING ON THE NATURE OF VARIABLE LOADING

https://doi.org/10.26896/1028-6861-2018-84-3-43-51

Abstract

Duration of growth of the fatigue crack of various steels such as AISI 4030, 40X, 40 at external excitation of various character is investigated. It should be noted that kinetics of the crack growth depends on the nature of variable loading in many respects. Experimental data of kinetics of fatigue cracks’ growth of the wide spectrum of block and random loadings of investigated steels are received and an approach for cracks’ growth estimate depending on material properties and the nature of variable external input is offered. It is shown that the duration of growth of the fatigue crack on the middle-amplitude segment of its growth depends on the completeness (irregularity) of block or accidental loading. It is offered the dependence of the longevity evaluation of fatigue crack durability from a given target size to its critical value corresponding to the moment of material destruction. For this calculation it was used the value of the fatigue crack growth duration was used at a zero regular loading with the maximum load corresponding to the maximum load of the later used block or accidental loading, also the fatigue properties of the material determined from the slope of the endurance curve under soft symmetrical loading were taken into account. The second approach is related to the application of averaged parameters of the fatigue crack growth kinetics — the slope of curve of the kinetic fatigue fracture diagram (KFFD) at regular cyclic loading with the same force parameters. The linear principle of summation of crack growth without interaction of amplitudes was used in both cases. For the study the accepted assumptions it was made a calculation of the duration growth of cracks in the program of summation the crack growth for each loading cycle (cycle-by-cycle) without taking into account the interaction of load amplitudes.

About the Authors

A. N. Savkin
Volgograd state technical university.
Russian Federation
Volgograd.


A. V. Andronik
Volgograd state technical university.
Russian Federation
Volgograd.


K. A. Badikov
Volgograd state technical university.
Russian Federation
Volgograd.


A. A. Sedov
Volgograd state technical university.
Russian Federation
Volgograd.


References

1. Nesterenko G. I. Fatigue and survivability of designs of the growing old planes / Trudy TsAGI. 1998. Issue 2631. P. 67 – 72 [in Russian].

2. Kheivud R. B. Design for fatigue. — Moscow: Mashinostroenie, 1969. — 504 p. [in Russian].

3. Savkin A. N., Bagmutov V. P. Forecasting of fatigue endurance of the heavy loaded constructions. — Volgograd: VolgGTU, 2013. — 364 p. [in Russian].

4. Panasyuk V. V. Fracture mechanics and material strength Reference book. Vol. 4. — Kiev: Naukova dumka, 1988 – 1990. — 640 p. [in Russian].

5. Scorupa M. Load interaction effects during fatigue crack growth under. Part I. Empirical trends / Fatique Fract. Engineer. Matem. Struct. 1998. P. 987 – 1006.

6. Scorupa M. Load interaction effects during fatigue crack growth under variable amplitude loading — a literature review. Part II. Qualitative interprйtation / Fatigue Fract. Engineer. Mater. Struct. 1999. P. 905 – 927.

7. Kihl D. P. Stochastic fatigue concepts in welded surface scup structures. Departamental Report SSPD-90-173-25. — US Navy: David Taylor Research Center, Beteshda. 1999.

8. Paris P. C., Erdogan F. A. Critical Analysis of Crack Propagation Laws / Journal of Basic Engineering; Transaction, American Society of Mechanical Engineers. Series D. 1963. Vol. 85. P. 528 – 534.

9. Savkin A. N., Andronik A. V., Koraddi R. Methods of determination of the crack growth rate equation coefficients at cyclic loading / Zavod. Lab. Diagn. Mater. 2016. Vol. 82. N 1. P. 57 – 63 [in Russian].


Review

For citations:


Savkin A.N., Andronik A.V., Badikov K.A., Sedov A.A. STUDY OF THE DURATION OF THE FATIGUE CRACK GROWTH IN STEELS DEPENDING ON THE NATURE OF VARIABLE LOADING. Industrial laboratory. Diagnostics of materials. 2018;84(3):43-51. (In Russ.) https://doi.org/10.26896/1028-6861-2018-84-3-43-51

Views: 583


ISSN 1028-6861 (Print)
ISSN 2588-0187 (Online)