Stress-Strain-Time Apparatus for Fiber Testing

Abstract

A stress‐strain apparatus for testing individual fibers is described. The apparatus employs a ring dynamometer in conjunction with a linear variable differential transformer. A constant rate of elongation apparatus is fully described and a schematic diagram of a constant rate of loading apparatus is discussed. The use of linear variable differential transformers allows simple a.c. amplifiers to be employed and thus removes many of the difficulties involved in d.c. bridge circuits. Load ranges from 50 grams to 1 gram per ten chart inches can be obtained with a sensitivity of several milligrams. By changing the size of the ring dynamometer employed, an apparatus giving the greater load ranges necessary to test yarns can be constructed.