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Single and repeated snatch loading of textile yarns, and the influence of temperature on the dynamic mechanical properties
Author(s) -
Swallow J. E.,
Webb M. W.
Publication year - 1964
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1964.070080116
Subject(s) - materials science , composite material , tension (geology) , tenacity (mineralogy) , modulus , stress (linguistics) , ultimate tensile strength , linguistics , philosophy
Yarns of nylon and polyethylene–terephthalate were subjected to snatch loadings of quarter period 5 × 10 −2 sec. and stress amplitudes up to break, by impacting at several known levels of energy. Force developed was measured as a function of time by means of a capacitance gauge, and the extension by photographing the movement of a small torch attached to the yarn. The equivalent linear modulus, calculated from the period of longitudinal oscillation at low energy input, agreed broadly with the initial modulus of the dynamic load‐extension curves. In repeated impact at a given energy level, the total deformation increased logarithmically with time, but the extension attributable to individual impacts decreased. There was a corresponding progressive increase in dynamic tension, but the breaking tension was not apparently affected either by the number of previous impacts or by the energy level. Breaking loads of a nylon yarn, reached in 10 −2 , 10, and 10 3 sec., were compared at temperatures from 20 to 250°C. Tenacity decreased with temperature at a rate depending on the time to break, but the tenacity at a temperature of about 240°C. was substantially independent of rate of loading. Strain‐time relationships, obtained at various temperatures using a photoelectric technique, were compared and analysed.