ISSN:
0021-8995
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
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 103 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.
Additional Material:
15 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1964.070080116
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