Abstract
The vibro-creep behavior of pure Nylon 6, 6 samples subjected to tensile-tensile cyclic loading conditions within the linear elastic region (25% of yield stress at 30 °C) was studied by examining their viscoelastic response. All tests were performed at controlled temperatures, and humidity was kept as low as possible. The test protocol included three frequencies and two amplitudes. The results from all tests show that vibro-creep behavior may be divided into three stages: (a) Primary thermally dominated regime (b) Transition or coupled regime (c) Tertiary damage dominated regime. The sample temperature was observed to rise 2–2.5 °C during the cyclic loading process, which significantly contributed to the early mechanical response of the sample. Two sets of quasi-static tests were completed at 30 °C and 32.5 °C to give references for vibro-creep effects. The relationship between engineering strain for the cyclic loading process (at 30 °C) and the quasi-static creep at 32.5 °C suggests the boundaries for different mechanisms dominating the vibro-creep behavior. This is also evident from the postmortem analyses of sample surfaces using AFM. Both the exterior sample surfaces and the interior cross-sectional surfaces were checked for the evolving damage. Mean roughness and dimensions of the cracks were measured in the damaged samples. Cracks of dimensions 2–4 μm on the exterior surface and 1–2 μm on the interior cross-sectional surface were observed in pure Nylon 6, 6 samples subjected up to 2 × 106 cycles.
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Liu, Z., Beniwal, S., Jenkins, C. et al. The Coupled Thermal and Mechanical Influence on a Glassy Thermoplastic Polyamide: Nylon 6, 6 Under Vibro-Creep. Mechanics of Time-Dependent Materials 8, 235–253 (2004). https://doi.org/10.1023/B:MTDM.0000046752.86686.cf
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DOI: https://doi.org/10.1023/B:MTDM.0000046752.86686.cf