Analysis of ductile and brittle failures from creep rupture testing of high-density polyethylene (HDPE) pipes

Krishnaswamy, Rajendra K.

doi:10.1016/j.polymer.2005.09.084

Cited by 120 publications

(58 citation statements)

References 40 publications

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“…Lifetimes under constant static loads are mainly predicted by fitting the data obtained from the experiments. [3,4] Polymer components or parts can also be subjected to cyclic or alternating loads known as cyclic fatigue behavior. Fatigue lifetimes are typically obtained by testing and described by S-N curves (stress vs. number of cycles to failure).…”

Section: Introductionmentioning

confidence: 99%

Creep–Fatigue Relationship in Polymer: Molecular Dynamics Simulations Approach

Sahputra

Echtermeyer

2014

Macro Theory & Simulations

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The creep-tensile fatigue relationship is investigated using MD simulations for amorphous polyethylene, by stepwise increasing the R-ratio from 0.3 for fatigue to an R-ratio ¼ 1 for creep. The simulations can produce similar behavior as observed in experiments, for instances strain-softening behavior and hysteresis loops in the stressstrain curves. The simulations predict the molecular mechanisms of creep and fatigue are the same. Fatigue and creep cause significant changes of the van der Waals and dihedral potential energies. These changes are caused by movements of the polymer chains, creating more un-twisted dihedral angles and the unfolding of polymer chains along the loading direction.

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Section: Introductionmentioning

confidence: 99%

Creep–Fatigue Relationship in Polymer: Molecular Dynamics Simulations Approach

Sahputra

Echtermeyer

2014

Macro Theory & Simulations

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“…5, it suffices to note that d i dt =˙ min during the secondary stage of creep and to apply Eq. 10 with i = C. Experimental data on polymers and polymer composites (Barton and Cherry 1979;Brown 1990, 1991;Teoh et al 1992;Ben Hadj Hamouda et al 2001, 2007Krishnaswamy 2005Krishnaswamy , 2007 demonstrate that Eq. 2 predicts the effect of stress σ on time to failure t f at relatively large (sub-yield) stresses only.…”

mentioning

confidence: 99%

Creep failure of polypropylene: experiments and constitutive modeling

Drozdov

Christiansen

2009

Int J Fract

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Observations are reported on isotactic polypropylene in uniaxial tensile tests with various strain rates, relaxation tests with various strains, and creep tests with various stresses at ambient temperature. Constitutive equations are derived for the viscoelastic-viscoplastic responses and damage of a semicrystalline polymer at three-dimensional deformations. Adjustable parameters in the stress-strain relations are found by fitting the experimental data. The model is applied to predict creep-failure diagrams in the entire interval of stresses. A phenomenological approach is proposed to determine a knee stress, at which transition occurs from ductile to brittle rupture. Accuracy of this method is evaluated by numerical simulation.

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“…and/or handling (scratches), and the crack propagation rate, which strongly depends on loading and environmental conditions. [2][3][4][5] To evaluate the crack propagation kinetics experimentally, a variety of methods can be used to monitor the crack length in time; some are specific to the type of material.…”

Section: A N U S C R I P Tmentioning

confidence: 99%