A model for non-linear creep in polypropylene

Dean, G; Broughton, W R

doi:10.1016/j.polymertesting.2007.07.011

Cited by 39 publications

(31 citation statements)

References 11 publications

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“…A number of studies in the literature have investigated creep behavior of neat polymers including damage mechanism [3], nonlinear creep behavior and modeling [4], superposition methods for long-term creep predictions considering environmental effects [5e7], and creep rupture behavior and predictions [8,9]. Seltzer et al [10] studied the effect of organoclay on creep behavior of injection molded polyamide-6 using dynamic mechanical analysis (DMA) in cantilever-bending.…”

Section: Introductionmentioning

confidence: 99%

Creep behavior and modeling of neat, talc-filled, and short glass fiber reinforced thermoplastics

Eftekhari

Fatemi

2016

Composites Part B: Engineering

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Section: Introductionmentioning

confidence: 99%

Creep behavior and modeling of neat, talc-filled, and short glass fiber reinforced thermoplastics

Eftekhari

Fatemi

2016

Composites Part B: Engineering

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“…Under these circumstances, the parameter t 0 is changing with time, even under a constant stress, as the polymer ages. The strain history produced by a time varying stress will be obtained by incorporating equation (11) into equation (10) to give e(t)ð Relationships between multiaxial stresses and strains involve the use of tensor stress and strain components s ij (t) and e ij (t) which, in general will be time dependent. The stress and strain tensors can be decomposed into their deviatoric and hydrostatic parts as follows…”

Section: Non-linear Behaviour Under Uniaxial Tensionmentioning

confidence: 99%

“…The main factor contributing to this non-linear behaviour is a reduction in the retardation time parameter t 0 with increasing stress. [6][7][8][9][10] The effect of elevated stresses is therefore to increase molecular mobility so that the polymer creeps faster. Non-linearity is therefore an inherent feature of viscoelastic behaviour.…”

Section: Introductionmentioning

confidence: 99%

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Modelling long term deformation behaviour of polymers for finite element analysis

Dean

McCartney

Crocker

et al. 2009

Plastics, Rubber and Composites

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Creep studies have been carried out under uniaxial tension and uniaxial compression on poly(oxymethylene). Measurements under tension have been modelled using a function with four material parameters. One of these parameters, related to a mean retardation time for the relaxation process responsible for creep, decreases with increasing stress, and this gives rise to non-linear creep behaviour. Measurements of creep under compression indicate that the retardation time parameter is determined by the stress state as well as the stress magnitude. A theoretical extension of the model has been proposed that relates stresses and strains under situations where the stress is not constant but varies with time. This is necessary for the model to be implemented in a finite element system to carry out design calculations that take proper account of the time dependent properties of polymers. The validity of the theory is evaluated through the use of the creep model to predict deformation for a variety of simple stress and strain histories under uniaxial tension. The close agreement between calculation and measurement supports the development of code, in future work, to obtain solutions for multiaxial stresses and strains using a finite element system.

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“…Especially low creep resistance of PP can be considered as a limiting factor for possible applications such as conveyor belts and shelves which require long‐term dimensional stability under a particular load. Creep behaviors of PP under different dynamic conditions have been investigated and the resulting viscoelastic and viscoplastic deformations and failure mechanism have been reported, in detail . Several attempts have been developed to improve the creep resistance of PP.…”

Section: Introductionmentioning

confidence: 99%

Quantifying Structural and Solid‐State Viscoelastic Properties of Poly(propylene) (PP)/Poly(oxymethylene) (POM) Blend Films

Kaşgöz

Akın

Durmuş

2016

Macro Materials & Eng

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In this study, isotactic poly(propylene) (PP)/poly(oxymethylene) (POM) blend films, including of POM as minor phase in the range of 10–30 wt%, are prepared in a twin screw extruder equipped with a slit‐die and cast film haul‐off unit. It is found that the blend films show characteristic immiscible matrix‐droplet morphology. Short‐term uniaxial tensile creep behaviors of films imply that the introducing of POM significantly improves the elastic modulus and decreases the total creep strain of PP/POM blends. Creep tests are also performed at various temperatures and long‐term deformations of samples are predicted by applying of time‐temperature superposition principle and the Findley model. It is found that the presence of POM domains into PP matrix enhances the creep resistance of PP especially at high temperatures. It is concluded that the PP‐rich PP/POM blend films show much lower short and long‐term creep strains compared to PP.

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A model for non-linear creep in polypropylene

Cited by 39 publications

References 11 publications

Creep behavior and modeling of neat, talc-filled, and short glass fiber reinforced thermoplastics

Creep behavior and modeling of neat, talc-filled, and short glass fiber reinforced thermoplastics

Modelling long term deformation behaviour of polymers for finite element analysis

Quantifying Structural and Solid‐State Viscoelastic Properties of Poly(propylene) (PP)/Poly(oxymethylene) (POM) Blend Films

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