Please use this identifier to cite or link to this item: http://ena.lp.edu.ua:8080/handle/ntb/49618
Title: Experimental determination of critical strain energy density of ductile materials
Authors: Molkov, Yuriy
Ivanyts’kyi, Yaroslav
Lenkovs’kyi, Taras
Trostianchyn, Andriy
Kulyk, Volodymyr
Shyshkovskyy, Roman
Affiliation: Karpenko Physico-mechanical Institute of the NAS of Ukraine
Lviv Polytechnic National University
Bibliographic description (Ukraine): Experimental determination of critical strain energy density of ductile materials / Yuriy Molkov, Yaroslav Ivanyts’kyi, Taras Lenkovs’kyi, Andriy Trostianchyn, Volodymyr Kulyk, Roman Shyshkovskyy // Ukrainian Journal of Mechanical Engineering and Materials Science. — Lviv : Lviv Politechnic Publishing House, 2019. — Vol 5. — No 1. — P. 39–44.
Bibliographic description (International): Experimental determination of critical strain energy density of ductile materials / Yuriy Molkov, Yaroslav Ivanyts’kyi, Taras Lenkovs’kyi, Andriy Trostianchyn, Volodymyr Kulyk, Roman Shyshkovskyy // Ukrainian Journal of Mechanical Engineering and Materials Science. — Lviv : Lviv Politechnic Publishing House, 2019. — Vol 5. — No 1. — P. 39–44.
Is part of: Український журнал із машинобудування і матеріалознавства, 1 (5), 2019
Ukrainian Journal of Mechanical Engineering and Materials Science, 1 (5), 2019
Journal/Collection: Український журнал із машинобудування і матеріалознавства
Issue: 1
Volume: 5
Issue Date: 20-Mar-2019
Publisher: Видавництво Львівської політехніки
Lviv Politechnic Publishing House
Place of the edition/event: Львів
Lviv
Keywords: strain energy density
stress-strain curve
true stress
true strain
Bridgman specimen
digital image correlation
strain-controlled loading
alloyed steel
Number of pages: 6
Page range: 39-44
Start page: 39
End page: 44
Abstract: The method of experimental determination of strain energy density of plastic materials is developed. The technique for complete true stress-strain curves plotting is formulated. The standard hydraulic testing machine is equipped with specially designed experimental setup for Bridgman specimens testing at strain controlled tension loading with digital camera and light source for using digital image correlation method – a non-contact technique for strain and displacement measurement. The digital image correlation method was used to determine the local strain at the onset of fracture in the neck of Bridgman specimen. The technique takes into account the change of crosssection area in the neck of specimen due to internal crack propagation when calculating the true stresses. The complete true stressstress-curve of 40Kh alloyed steel is plotted end criticalstrain energy density of steel is determined from it. It is shown that the critical strain energy density of material, determined from the curve obtained by developed technique is 1.8 times higher than determined from the classical true stress-strain curve and is close to the value of the specific heat of fusion of steel. The curves built using the proposed technique can be used for setting material properties in stress-strain state calculations by finite element method at large scale yielding conditions, for instance at pressure vessels critical pressure calculation. The critical strain energy density value can be considered as a material property at fatigue life-time calculation using energy approach.
URI: http://ena.lp.edu.ua:8080/handle/ntb/49618
Copyright owner: © Національний університет “Львівська політехніка”, 2019
© Molkov Yu., Ivanyts’kyi Ya., Lenkovs’kyi T., Trostianchyn A., Kulyk V., Shyshkovskyy R., 2019
References (Ukraine): 1. Yu. Du, et al., “Analysis of the stress-strain state of the process zone of a plate with central crack under biaxial loading,” Materials Science, vol. 53, no. 1, pp. 86–92, 2017.
2. Yu. V. Mol’kov, “Experimental determination of the specific strain energy of 65G steel under cyclic loading,” Materials Science, vol. 52, no. 4, pp. 522–529, 2017.
3. H. J. Shindler, “Strain energy density as the link between global and local ap p roach to fracture”, in Proc. of 10th Int. Conf. on Fracture, Honolulu, 2001.
4. L. F. Gillemot, “Criterion of crack initiation and spreading,” Engineering Fracture Mechanics, vol. 8, no. 1, pp. 239–253, 1976.
5. A. Valiente, “On Bridgman’s stress solution for a tensile neck applied to axisymmetrical blunt notched tension bars,” J. Appl. Mech., vol. 68, no. 3, pp. 412–419, 2000.
6. M. A. Sutton, M. Cheng, W. H Peters, et al., “Application of an optimized digital correlation method to planar deformation analysis,” Image Vision Comput., vol. 4, no. 3, pp. 143–150, 1986.
7. B. Pan, K. M. Qian, H. M. Xie, and A. Asundi, “Two-dimensional digital image correlation for in-plane displacement and strain measurement: a review,” Meas. Sci. Technol., vol. 20, no. 6, pp. 062001–062007, 2009.
8. Z. Wang, “On the accuracy and speed enhancement of digital image correlation technique,” J. Exper. Mech., vol. 26, no. 5, pp. 632–638, 2011.
9. Yu. V. Mol’kov, “Otsiniuvannia opirnosti ruinuvanniu yemnostei pid tyskom iz vykorystanniam enerhetychnoho pidkhodu” [“Evaluation of pressure vessels fracture resistance using energy approach”], Ph.D. dissertation, Karpenko physico-mechanical institute of the NAS of Ukraine, Lviv, Ukraine, 2014. [in Ukrainian].
10. Yu. V. Mol’kov, “Application of the method of digital image correlation to the construction of stress–strain diagrams,” Materials Science, vol. 48, no. 6, pp. 832–837, 2013.
11. A. Kalup, M. Žaludová, S. Zlá, et al., “Latent heats of melting and solidifying of real steel grades”, in Proc. 23rd International Conference on Metallurgy and Materials (METAL-2014), Brno, Czech Republic, 2014, pp. 695–700.
12. Th. H. Courtney, Mechanical behaviour of materials. Long Grove, IL: Waveland Press, 2005.
References (International): 1. Yu. Du, et al., "Analysis of the stress-strain state of the process zone of a plate with central crack under biaxial loading," Materials Science, vol. 53, no. 1, pp. 86–92, 2017.
2. Yu. V. Mol’kov, "Experimental determination of the specific strain energy of 65G steel under cyclic loading," Materials Science, vol. 52, no. 4, pp. 522–529, 2017.
3. H. J. Shindler, "Strain energy density as the link between global and local ap p roach to fracture", in Proc. of 10th Int. Conf. on Fracture, Honolulu, 2001.
4. L. F. Gillemot, "Criterion of crack initiation and spreading," Engineering Fracture Mechanics, vol. 8, no. 1, pp. 239–253, 1976.
5. A. Valiente, "On Bridgman’s stress solution for a tensile neck applied to axisymmetrical blunt notched tension bars," J. Appl. Mech., vol. 68, no. 3, pp. 412–419, 2000.
6. M. A. Sutton, M. Cheng, W. H Peters, et al., "Application of an optimized digital correlation method to planar deformation analysis," Image Vision Comput., vol. 4, no. 3, pp. 143–150, 1986.
7. B. Pan, K. M. Qian, H. M. Xie, and A. Asundi, "Two-dimensional digital image correlation for in-plane displacement and strain measurement: a review," Meas. Sci. Technol., vol. 20, no. 6, pp. 062001–062007, 2009.
8. Z. Wang, "On the accuracy and speed enhancement of digital image correlation technique," J. Exper. Mech., vol. 26, no. 5, pp. 632–638, 2011.
9. Yu. V. Mol’kov, "Otsiniuvannia opirnosti ruinuvanniu yemnostei pid tyskom iz vykorystanniam enerhetychnoho pidkhodu" ["Evaluation of pressure vessels fracture resistance using energy approach"], Ph.D. dissertation, Karpenko physico-mechanical institute of the NAS of Ukraine, Lviv, Ukraine, 2014. [in Ukrainian].
10. Yu. V. Mol’kov, "Application of the method of digital image correlation to the construction of stress–strain diagrams," Materials Science, vol. 48, no. 6, pp. 832–837, 2013.
11. A. Kalup, M. Žaludová, S. Zlá, et al., "Latent heats of melting and solidifying of real steel grades", in Proc. 23rd International Conference on Metallurgy and Materials (METAL-2014), Brno, Czech Republic, 2014, pp. 695–700.
12. Th. H. Courtney, Mechanical behaviour of materials. Long Grove, IL: Waveland Press, 2005.
Content type: Article
Appears in Collections:Ukrainian Journal of Mechanical Engineering And Materials Science. – 2019. – Vol. 5, No. 1



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