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Journal ArticleDOI

Influence of absorbed moisture on fatigue crack propagation behaviour in polyamides

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TLDR
In this paper, the effect of plasticization on the fatigue crack propagation response in polyamides was examined by conducting fatigue tests on specimens of nylon 66 (N66), nylon 6 (N6) and nylon 612 (N612) which had been equilibrated at various levels of absorbed water.
Abstract
The effect of plasticization on the fatigue crack propagation response in polyamides was examined by conducting fatigue tests on specimens of nylon 66 (N66), nylon 6 (N6) and nylon 612 (N612) which had been equilibrated at various levels of absorbed water. In N66 and N6, crack growth rates decreased as the water content was increased to about 2.5wt%; with increasing moisture content, FCP rates increased and at saturation (8.5 wt% H2O) FCP rates were higher than those observed in the dry polymer. Crackgrowth rates in N612 decreased monotonically as the water content increased to saturation (3.2 wt% in this polyamide). These results were interpreted in terms of the competition between enhanced crack-tip blunting and lowering of the specimen modulus. Crack-tip blunting was believed to dominate fatigue behaviour at low water contents (⩽2.5wt%) and contributed to reduced FCP rates. The higher crack-growth rates observed at higher moisture levels were believed to be caused by reductions in material stiffness.

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Citations
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Journal ArticleDOI

Effect of humidity on the indentation hardness and flexural fatigue behavior of polyamide 6 nanocomposite

TL;DR: In this article, the effect of relative humidity on indentation hardness and flexural fatigue behavior of polyamide 6 nanocomposites is reported. And failure mechanisms at different humidity levels are discussed.
Book ChapterDOI

Mechanical Performance of Polyamides with Influence of Moisture and Temperature – Accurate Evaluation and Better Understanding

TL;DR: In this paper, the impact of moisture and temperature on polyamides strength and ductility was investigated under dry-as-molded conditions, and the tensile properties of conditioned polyamide were obtained from − 40°C to 150°C and the moisture content in the sample was examined immediately after test.
Journal ArticleDOI

Fatigue fracture of nylon polymers: Part 1 Effect of frequency

TL;DR: In this article, the effect of frequency on fatigue crack propagation rates in unfilled nylon polymers was investigated under conditions where hysteretic heat generation did not occur, and it was shown that a strong frequency dependence exists with higher crack propagation rate at lower frequencies.
Journal ArticleDOI

Fatigue crack propagation in glass-fibre and glass-sphere filled PBT composites

TL;DR: In this article, the influence of crack propagation direction and micro-structural composition on crack speed was discussed and it was found that a model which accounts for the fibre orientation distribution, the skin morphology and the change in failure mechanisms due to variations in the fibre length and aspect ratio can explain the differences observed in crack propagation behavior.
Journal ArticleDOI

Fatigue fracture of nylon polymers

TL;DR: In this article, the influence of glass fibres on the fatigue crack propagation rates of injection-moulded nylons has been determined, and it is concluded that the fatigue fracture mechanism is matrix dominated in these reinforced materials.
References
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Book

Anelastic and Dielectric Effects in Polymeric Solids

TL;DR: Menard et al. as mentioned in this paper discuss the use of dynamic mechanical analysis (DMA) as a tool for thermal analysis, rheology, and materials science in the analytical laboratory.
Book

Handbook of Tables for Applied Engineering Science

TL;DR: In this article, a comprehensive index of properties of materials and composites is presented, with detailed indexing by name, class and usage, with cross references and numerically keyed subject headings at the top of each page.
MonographDOI

Water in Polymers

Journal ArticleDOI

Variability in fatigue crack growth rate testing

TL;DR: In this paper, an extensive interlaboratory (round robin) program was conducted and the variability and bias associated with the current state of the art of fatigue crack growth rate testing was determined.
Journal ArticleDOI

On the generality of discontinuous fatigue crack growth in glassy polymers

TL;DR: In this article, the fracture surface characteristics of five commercially available amorphous polymers [poly(methylmethacrylate) (PMMA), polycarbonate (PC), polyvinyl chloride (PVC), polystyrene (PS), and polysulphone (PSF) were studied to determine if common mechanisms of fatigue crack propagation prevail among these glassy polymers.
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