Abstract
In this paper, an experimental and a numerical analysis were carried out using High density polyethylene (HDPE). Sheets with an initial central crack (CCT specimens) inclined with a given angle are investigated and compared to the loading direction. The kinking angle is experimentally predicted and numerically evaluated under mixed mode (I+II), as a function of the strain energy density (SED) around the crack-tip, using the Ansys Parametric Design Language (APDL).According to the experimental observations and numerical analysis, the plan of crack propagation is perpendicular to the loading direction. Moreover, as suggested by Sih in the framework of linear elastic fracture mechanics (LEFM), the minimum values Sminof the factor S are reached at the points corresponding to the crack propagation direction. These results suggest that the concept of the strain energy- density factor can be used as an indicator of the crack propagation direction.
Highlights
Thanks to many advantages which the high-density polyethylene (HDPE) has, it is highly used in the networks of drinking water
At present, studying crack propagations’ direction has been made possible by Finite Element Method (FEM), and the prediction of crack initiation angle in components is accessible by the fracture mechanics approaches, according to these approaches, the fracture process is assumed to be initiated from the pre-existing defects cited previously [1]
For various crack inclined angle, the kinking angle is evaluated as a function of the Minimum Strain Energy Density (MSED) around the crack tip
Summary
Thanks to many advantages which the high-density polyethylene (HDPE) has, it is highly used in the networks of drinking water. Since 2003, several water distributers noted premature failures of connections in HDPE, in particular, when the pipeline is subjected to bending or stretching. The major source of failure of structural components is crack growth for such reason, defects and pre-cracks may be introduced in HDPE pipelines during installation, repair or by accident. At present, studying crack propagations’ direction has been made possible by Finite Element Method (FEM), and the prediction of crack initiation angle in components is accessible by the fracture mechanics approaches, according to these approaches, the fracture process is assumed to be initiated from the pre-existing defects cited previously [1].
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