Modeling of fatigue damage accumulation in structural steels under low-cycle block loading
DOI:
https://doi.org/10.7242/1999-6691/2014.7.1.2Keywords:
damaged media model, low-cycle fatigue, damage, block cyclic loading, experiment, calculationAbstract
The process of low-cycle fatigue of structural steels under arbitrary thermal loading is modeled within the framework of mechanics of defective materials. The development of the model of damaged medium involves three steps: - thermo-plastic equations are derived using the concept of surface creep and its transformation under thermal mechanical loading. This variant of thermo-plastic equations describes the main effects of complex plastic deformation of metals and their alloys; - kinetic equations of fatigue damage accumulation are derived by studying the physical stages of development of micro-defects. The equations are based on energy principles and take into account the influence of deformation path conditions, the type of stress state, and the level of damage accumulation on the rate of accumulation of fatigue damages; - condition for critical damage value is taken as a criterion for macroscopic crack formation. The results of a comparative study of the proposed model and the J.L. Chaboche model underlying the modern finite-element analysis code ANSYS are presented. It is shown that the thermo-plastic equations coincide with each other up to constants, and for regular loading cycles the equations of damage accumulation curve and the failure criterion are identical. The experimental study of fatigue damage accumulation in the laboratory samples made of 08Х18Н10Т austenitic steel subjected to double-block low-cycle loading was carried out. Comparison of the experimental and calculated data shows that the model of damaged media developed by the authors can adequately represent the process of fatigue damage accumulation under block low-cycle loading. The possibility to use the Palmgren-Miner linear damage summation in the case of block loading modes is studied. It has been found that such an approach to calculations of the fatigue life under irregular loading can provide both the conservative and non-conservative assessment of the fatigue life.
Downloads
References
Hautmann S., Gottsmann J., Sparks R.S.J., Costa A., Melnik O., Voight B. Modelling ground deformation caused by oscillating overpressure in a dyke conduit at Soufriere Hills Volcano, Montserrat // Tectonophysics. - 2009. - Vol. 471, no. 1-2. - P. 87-95. DOI
2. Costa A., Melnik O., Sparks R.S.J., Voight B. Control of magma flow in dykes on cyclic lava dome extrusion // Geophys. Res. Lett. - 2007. - Vol. 34, no. 2. - L02303. DOI
3. http://www.mufits.imec.msu.ru (data obrasenia: 30.01.2015).
4. Mueller S., Melnik O., Spieler O., Scheu B., Dingwell D.B. Permeability and degassing of dome lavas undergoing rapid decompression: An experimental determination // B. Volcanol. - 2005. - Vol. 67, no. 6. - P. 526-538. DOI
5. Navon O., Lyakhovsky V. Vesiculation processes in silicic magmas // The physics of explosive volcanic eruption / Ed. by J. Gilbert, R.S.J. Sparks. - London: Geological Society, Special Publication, 1998. - Vol. 145. - P. 27-50. DOI
6. Hort M. Abrupt change in magma liquidus temperature because of volatile loss or magma mixing: effects on nucleation, crystal growth and thermal history of the magma // J. Petrology. - 1998. - Vol. 39, no. 5. - P. 1063-1076. DOI
7. Mushelisvili N.I. Nekotorye osnovnye zadaci matematiceskoj teorii uprugosti. - M: Nauka, 1966. - 708 s.
8. Afanas’ev A.A. Matematiceskaa model’ neizotermiceskoj mnogofaznoj fil’tracii binarnoj smesi // MZG. - 2011. - T. 46, No 1. - S. 104-115. DOI
9. Afanas’ev A.A., Mel’nik O.E. O postroenii konecno-raznostnoj shemy rasceta fil’tracii pri okolokriticeskih termodinamiceskih usloviah // Vycisl. meh. splos. sred. - 2013. - T. 6, No 2. - S. 246-255. DOI
10. Afanas’ev A.A., Mel’nik O.E. Ob odnom metode rasceta teplofiziceskih svojstv pri do- i zakriticeskih usloviah // Fiziko-himiceskaa kinetika v gazovoj dinamike. - 2013. - T. 14. (URL: http://chemphys.edu.ru/media/files/2013-04-04-001.pdf).
11. Brooks R.H., Corey A.T. Hydraulic properties of porous media // Hydrology Papers. - Colorado State University, 1964. - No. 3. - 27 p.
12. Rinaldi A.P., Todesco M., Bonafede M. Hydrothermal instability and ground displacement at the Campi Flegrei caldera // Phys. Earth Planet In. - 2010. - Vol. 178, no. 3-4. - P. 155-161. DOI
13. Wang H.F. Theory of linear poroelasticity with applications to geomechanics and hydrology. - Princeton University Press, Princeton and Oxford, 2000. - 276 p.
14. Mindlin R.D. Force at a point in the interior of a semi-infinite solid // J. Appl. Phys. - 1936. - Vol. 7, no. 5. - P. 195. DOI
15. Mattioli G.S., Herd R.A., Strutt M.H., Ryan G., Widiwijayanti C., Voight B. Long term surface deformation of Soufriere Hills Volcano, Montserrat from GPS geodesy: Inferences from simple elastic inverse models // Geophys. Res. Lett. - 2010. - Vol. 37, no. 19. - L00E13. DOI
Downloads
Published
Issue
Section
License
Copyright (c) 2014 Computational Continuum Mechanics
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.