مدلسازی عددی و اعتبار سنجی آزمایشگاهی در تعیین چقرمگی مود بازشونده ترک در بتن با استفاده از آزمایش دیسک برزیلی درزه دار

نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشکده مهندسی عمران، دانشگاه صنعتی شریف، تهران، ایران

2 دانشکده مهندسی معدن، دانشگاه صنعتی همدان، همدان، ایران

3 استاد، دانشکده مهندسی عمران، دانشگاه صنعتی شریف

4 دانشکده مهندسی معدن، دانشگاه ازاد اسلامی واحد بافق، بافق، ایران

چکیده

در این مقاله با استفاده از کد جریان ذره دو بعدی و تست های آزمایشگاهی چقرمگی مود بازشونده ترک در بتن توسط آزمایش دیسک برزیلی درزه دار تعیین و نتایج مدلسازی و یافته های آزمایشگاهی مقایسه شدند. به این منظور دو نمونه دیسکی بتنی به قطر mm 54 و ضخامت mm 27 آماده شد. این نمونه دارای یک درزه مرکزی به طول mm 20 و بازشدگی mm 1 است. نمونه ها از ترکیب آب، شن ریزدانه و سیمان با نسبت 1-5/0-1ساخته می شود. نمونه دیسکی شکل تحت بارمحوری قرار می گیرد. شبیه سازی عددی توسط کد جریان ذره دوبعدی نیز برای اعتبار سنجی نتایج آزمایشگاهی انجام شد. نتایج نشان می دهد که ترک از نوک درزه ایجاد شده و به موازات بارگذاری رشد کرده و به لبه نمونه متصل می شود. این الگوی رشد ترک در تطابق خوبی با نتایج آزمایشگاهی است. چقرمگی شکست بدست آمده از دو روش آزمایشگاهی و عددی نیز با یکدیگر مشابه هستند.

کلیدواژه‌ها


عنوان مقاله [English]

Numerical and Experimental Investigation for Determining the Opening Mode Toughness of Concrete Using Cracked Brazilian Disk Test

نویسندگان [English]

  • Hadi Haeri 1
  • Vahab Sarfarazi 2
  • Alireza Khaloo 3
  • Mohsen Farazmand 4
1 Department of Civil Engineering, Sharif University of Technology, Tehran, Iran
2 Department of Mining Engineering, Hamedan University of Technology, Hamedan, Iran
3 Distinguished Professor, Department of Civil Engineering, Sharif University of Technology, Tehran, Iran
4 Department of Mining Engineering, Bafgh Branch, Islamic Azad University, Bafgh, Iran
چکیده [English]

In this paper, a simultaneous experimental and numerical analysis of opening mode toughness in The Pre-joined Brazilian disc using Brazilian tests are carried out. These numerical results are compared with the existing experimental results. For this purpose, two concrete disc specimens of 54 mm diameter and 27 mm thick were prepared. These specimens have a central joint of 20 mm in length and an opening in mm 1. Specimens are made from a mixture of water, fine sand, and cement with a ratio of 1-5 / 0-1. The same specimens are numerically simulated by a two-dimensional particle flow code (PFC).The results indicate that the crack formed from the tip of the joint and grows parallel to the load and connects to the edge of the specimen. The Fracture toughness obtained from the numerical method is in good agreement with experimental results.

کلیدواژه‌ها [English]

  • Opening-Mode Fracture Toughness
  • Pre-Cracked Brazilian disk
  • Code Particle Flow (PFC)
  1. Kaplan, M) 1961 (Crack propagation and the fracture of Concrete", American Concrete Institute ACI. J.,58 (5), 591-610.
  2. Shah, S. P., and Mac-Garry, F. J. (1971). Griffith fracture criterion and concrete. J of Eng MecDivision, Vol, 97: 1663-1676.
  3. Broek D. (1982). Elementary engineering fracture mechanics. Martinus nijhoff publishers, Boston.
  4. Schmidt, R. A. (1976). Fracture toughness testing of Limestone, Expl. Mech., 16, 161-167.
  5. Clifton, R. J. Simonson, E. R., Jones, A. H. & Green, S. J. (1976). Determination of the critical stress intensity factor, KIC, from internally pressurized thick-walled vessels, Expl. Mech., 16:  233- 238.
  6. Zoback, M. D. (1978). A simple hydraulic fracturing technique for determining rock fracture toughness, Proc. 19th U.S. Symp. On Rock Mechanics, University of Nevada, Reno, pp83-85.
  7. Ouchterlony, F. (1982). A review of fracture toughness testing of rocks, Solid Mechanics Archives, 7, 131-211.
  8. Ouchterlony, F. (1986). A core bend specimen with chevron edge notch for fracture toughness measurements, Rock Mechanics: Key to Energy Production, Proc. 27th US Symp. On Rock Mech., H. L. Hartman, (Ed.), SME, Littleton Co., pp:177-184.
  9. ISRM (1988). Suggested methods for determining fracture toughness of rocks, F. Ouchterlony, Int. J. Rock. Mech. Min. sci. & Geomech. Abstr., 25, 71-96.
10.ISRM (1995). Suggested methods for determining mode I fracture toughness using cracked chevron notched Brazilian disk (CCNBD) specimens, R. J. Fowell, Int. J. Rock. Mech. Min. sci. & Geomech. Abstr. 32: 57-64.

11.Ingraffea, A. R. & Heuze, F. E. (1980). Finite element models for rock fracture mechanics, Int. J. Numl. & Analyl. Meths. Geomech., 4: 25-43.

12.Ingraffea, A. R. (1976). Fracture propagation in rock: Laboratory tests and finite element analysis, Proc. 17th US Symp. On Rock Mech. Snowbird, Utah, pp: 5C4-1 – 5C4-1-6.

13.Lim IL, Johnston IW, Choi SK, Boland JN.O. (1994). Fracture testing of a soft rock with semi-circular specimens under three-point bending. Part 2—mixed mode. Int J Rock Mech Min Sci Geomech Abstr 31(3):199–212.

14.Atkinson C, Smelser RE, Sanchez J. (1982). Combined mode fracture via the cracked Brazilian disc test. Int J Fract;18:279–91.

15.Chang SH, Lee CI, Jeon S. (2002). Measurement of rock fracture toughness under modes I and II and mixed-mode conditions by using disc- type specimen. Eng Geol;66:9–97.

16.Shetty DK, Rosenfield AR, Duckworth WH. (1987). Mixed-mode fracture in biaxial stress state: application of the diametral-compression (Brazilian disk) test. Eng Fract Mech;26(6):825–40.

17.Khan K, Al-Shayea NA. (2000). Effect of specimen geometry and testing method on mixed I–II fracture toughness of a limestone rock from Saudi Arabia. Rock Mech Rock Eng; 33(3):179–206.

18.Maccagno TM, Knott JF. (1989). The fracture behaviour of PMMA in mixed modes I and II. Eng Fract Mech;34(1):65–86.

19.He MY, Cao HC, Evans AG. Mixed-mode fracture: the four point shear specimen. Acta Metal Mater 1990;38:839–46.

20.Suresh S, Shih CF, Morrone A, O’Dowd NP. (1990). Mixed-mode fracture toughness of ceramic materials. J Am Ceram Soc ;73:1257–67.

21.Huang J, Wang S. (1985). An experimental investigation concerning the comprehensive fracture toughness of some brittle rocks. Int J Rock Mech Min Sci Geomech Abstr;22(2):99–104.

22.Buchholz FG, Pirro PJM, Richard HA, Dreyer KH. (1987). Numerical and experimental mixed- mode analysis of a compact tension-shear–specimen. In: Luxmoore et al., editors. Proceedings of the fourthInternational Conference Numer methods in fracture mechanics. Swansea: Pineridge Press; p: 641–56.

23.Mahajan RV, Ravi-Chandar K. (1989). An experimental investigation of mixed-mode fracture. Int J Fract;41:235–52.

24.Banks-Sills L, Bortman Y. (1986). A mixed mode fracture specimen; analysis and testing. Int J of Fract; 30:181–201.

25.Chong KP, Kuruppu MD. (1984). New specimen for fracture toughness determination for rock and other materials. Int J Fract; 26:  R59–62.

26.Chong KP, Kuruppu MD. (1987). Fracture toughness determination of layered materials. Eng Fract Mech; 28(1) :43–54.

27. Singh RN, Sun GX. (1990). A numerical and experimental investigation for determining fracture toughness of Welsh limestone. Min Sci Tech; 10: 61–70.

28.Haeri H, khaloo A, Maraji M., (2014).  experimental and numerical analysis of Brazilian discs with multiple parallel cracks. Arab J geosciences, doi 10.1007/s12517-014-1598-1.

29.Haeri H, Shahriar K, Marji MF, Moaref Vand P. (2014b). An experimental and numerical study of crack propagation and cracks coalescence in the pre-cracked rock-like disc specimens under compression. int j rock Mecha Min sci 67c:20  28

30.Haeri H, Shahriar K, Marji MF, Moaref Vand P. (2014c). On the HDD analysis of micro cracks initiation, propagation and coalescence in brittle substances. Arab J Geosc Pres Accept Manuscr. doi: 10.1007/s 1 25 17 -0 14 -1 29 0- 5

31.Haeri H, Shahriar K, Fatehi Marji M, Moarefvand P. (2014d). On the crack propagation analysis of rock like Brazilian disc specimens contain-ing cracks under compressive line loading. lat amer J solids struct 11 : 4 0 0 –1416

32.Griffith AA. (1921). The phenomena of rupture and flow in solids. The PhilosophicalTransactions of the Royal Society London (Series A);221:163- 98 .

33.Sarfarazi V, Ghazvinian A, Schubert W, Blumel M, Nejati HR. (2014). Numerical Simulation of the Process of Fracture of Echelon Rock Joints, Rock Mechanics and Rock Engineering,  47(4), 1355–1371.

34.BS1881 - 117: (1983). Testing Concrete - Method for determination of tensile splitting strength. British Standards Institute, London.

35.Potyondy, D., Cundall, P. (2004). A bonded-particle model for rock. Int J Rock Mech Min Sci and Geomech Abstr, Vol. 41, pp. 1329-1364.

36.Cundall P (1971). A computer model for simulating progressive large scale movements in blocky rock systems. In: Proceedings of the symposium of international society of rock mechanics, vol 1. Nancy, France. Paper no. II-8.