Experimental and Numerical Investigation on Mixed Mode Fracture of PMMA

Document Type : Research Article

Authors

1 applied design mechanical engineering, sahand university, tabriz, iran

2 associate professor/Mechanical Engineering Sahand University of Technology

Abstract

Existence a crack in structural parts is the main problem of predicting failure especially in mixed mode loading conditions. In most applications, fracture is happened under mode-I (tensile), mode- II (shear) or the combination of shear and tensile modes. Arcan test specimen was originally designed for use with composite materials, but in recent years has been adapted by many researchers for use with isotropic materials. In this paper, in an attempt to study the fracture toughness, test specimens were prepared in the form of butterfly from Polymethylmethacrylate polymer in specimen thickness of 10 mm. Experimental fracture tests were performed in three different crack lengths and first mode, mixed-mode and the pure second mode by changing the loading angle, using a specially developed fixture, based on Arcan. Load versus displacement curves were obtained. Furthermore, the fixture and specimen were modeled in ABAQUS/CAE, and stress intensity factors were derived. Using critical loads of the tests and the dimensionless stress intensity factors, obtained from the finite element analysis, fracture toughness of the polymer was determined. As the result, it can be seen that the shearing mode fracture toughness is larger than opening mode toughness. This means that cracked specimen is weaker in tensile loading. Finite element analysis was performed using elastic properties of the Poly methyl methacrylate polymer.

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[1]   Carrillo-Sánchez, F., G. Canche-Escamilla, and P. Herrera-Franco, A study of  the  fracture  toughness of acrylic composites using the essential work of fracture method. Polymer Testing, 2010. 29(5): p. 565-571.
[2]   Shokrieh, M. and A. ZEINEDINI, PREDICTION OF STRAIN ENERGY RELEASE RATE OF ASYMMETRIC DOUBLE CANTILEVER COMPOSITE BEAM IN MIXED-MODE I/II DELAMINATION USING EQUIVALENT LAY-UP FOR MIXED-MODE I/II DELAMINATION. 2014.
[3]     Anderson, T.L. and T.L. Anderson, Fracture mechanics: fundamentals and applications. 2005: CRC press.
[4]    MOHAMMAD, A.M. and E.M.R. AYAT, Fracture Toughness Evaluation for Brittle Polymers under Combined Tensile-shear Loading. 2008.
[5]   Yan, J.,  et  al.,  Evaluation  of  fracture  toughness  of human dentin using elastic–plastic fracture mechanics. Journal of Biomechanics, 2008. 41(6): p. 1253-1259.
[6]  Oskui, A.E.h. and N. Choupani, Development & Design of an Experimental Setup  for  Determining of Mixed Mode Fracture Toughness. MSc Thesis, Department of Mechanical Engineering, Sahand University of ….
[7]  Ayatollahi, M., M. Aliha, and M. Hassani, Mixed mode brittle fracture in PMMA—an experimental study using SCB specimens. Materials Science and Engineering: A, 2006. 417(1-2): p. 348-356.
[8]  Oskui, A.E.h., N. Choupani, and M. Shameli, 3D characterization of mixed-mode fracture  toughness of materials using a new loading device. Latin  American Journal of Solids and Structures, 2016. 13(8): p. 1464-1482.
[9]  Aliha, M., A. Bahmani, and S. Akhondi, Mixed mode fracture toughness testing of PMMA with different three-point bend type specimens. European Journal  of Mechanics-A/Solids, 2016. 58: p. 148-162.
[10]     Oskui, A.E.h., N. Choupani, and E. Haddadi, Experimental and numerical investigation of fracture of ABS polymeric material for different sample's thickness using a new loading device. Polymer Engineering & Science, 2014. 54(9): p. 2086-2096.
[11]      Khaliji, V., M. Yazdani, and N. Choupani, Experimental Determination of Translaminar Fracture Toughness of a woven glass epoxy composite Using New Fixture. Modares Mechanical Engineering, 2016. 15(11): p. 330-338.
[12]     Arcan, M., Z.a. Hashin, and A. Voloshin, A method to  produce  uniform  plane-stress  states  with applications to fiber-reinforced materials. Experimental mechanics, 1978. 18(4): p. 141-146.
[13]    Amstutz, B.E., et al., An experimental study of CTOD for mode I/mode II stable crack growth in  thin 2024-T3 aluminum specimens, in Fracture Mechanics: 26th Volume. 1995, ASTM International.
[14]   Choupani,    N.,    Experimental    and    numerical investigation of the mixed-mode delamination in Arcan laminated specimens. Materials Science and Engineering: A, 2008. 478(1-2): p. 229-242.
[15] Shameli, M., N. Choupani, and M.K. Razavi, Measurement of Mixed-mode Fracture  Toughness  of Polypropylene using Multi-specimen J-integral Method. Modares Mechanical Engineering, 2016. 16(4): p. 333-344.
[16] Chong, A.C., et al., Fracture toughness and fatigue crack propagation rate of short fiber reinforced epoxy composites for analogue cortical bone. Journal of biomechanical engineering, 2007. 129(4): p. 487- 493.
[17] Haddadi, E., N. Choupani, and F. Abbasi, Experimental and  Numerical  Investigation  of  Mode II Fracture Toughness of Rubber-Toughened Polymethyl Methacrylate by Using the Essential Fracture Work. Modares Mechanical Engineering, 2016. 16(3): p. 132-140.
[18] ABAQUS, A., Standard User's manual Version 6.5 Hibbit. Karlsson & Sorensen Inc., Pawtucket, RI, USA, 2004.
[19] Howard, S., Materials Data Book 2003 Edition. 2003, Cambridge University Engineering Department, Cambridge, UK.