A Slow Crack Growth Model for High-Density Polyethylene under Thermal and Chemical Environment

Nam, Hyun Young

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Overview

Year:: 2023
Contributor:: Nam, Hyun Young (creator); Srivastava, Vikas (Advisor); Brown University. Engineering: Mechanics of Solids (sponsor)
Genre:: theses
Subject:: Polymers; Solid Mechanics; Fracture mechanics
Extent:: 6, 24 p.

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Abstract:: High-density polyethylene (HDPE) is a widely used thermoplastic polymer with application as the material for pipeline transport systems. Due to the longterm, low-stress conditions of pipelines and the viscoelastic properties of HDPE, it is inevitable for the material to undergo a slow crack growth (SCG) failure mechanism. In addition to the applied loads, SCG is also affected by the chemical and thermal environments of the transport system. It is therefore crucial to develop a SCG model to more accurately predict the long-term failure of HDPE by taking into account the chemical and thermal effects. Experimental data was retrieved from literature of full notch creep tests (FNCT) performed at various temperatures and under chemical exposure to an environmental stress cracking (ESC) agent to develop this SCG model. The HDPE specimen time to failure (tf ) data was extracted in addition to the test specimen elongation (l ), which was then converted to crack-tip opening distance (COD, δ). The viscoelastic behavior of HDPE was captured through a Maxwell model consisting of four branches and a Prony series type model with parameters calibrated using the experimental data. Computational simulations were performed by implementing the model in a commercial finite element analysis software ABAQUS to obtain the mathematical relationship between elongation and COD. The COD data from different thermal and chemical exposure conditions to develop the SCG model. The model accurately predicted the long-term structural failure of HDPE observed in another data set used as validation obtained from literature. This model has application in the design and maintenance of HDPE pipelines for the transport system.
Notes:: Thesis (Sc. M.)--Brown University, 2023

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Citation

Nam, Hyun Young, "A Slow Crack Growth Model for High-Density Polyethylene under Thermal and Chemical Environment" (2023). Mechanics of Solids Theses and Dissertations. Brown Digital Repository. Brown University Library. https://repository.library.brown.edu/studio/item/bdr:cpd7mcqf/

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Mechanics of Solids Theses and Dissertations

Theses and Dissertations for the Mechanics of Solids department.
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