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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References

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Amirkabir Journal of Mechanical Engineering
Volume 51, Issue 5
November and December 2019
Pages 1077-1088

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