Findings and Recommendations on the Use of the Vibroscope

The vibroscope method of determining linear density of fibers is based on the prin ciple of the vibrating string, wherein the linear density is directly determined by tension and length of a fiber vibrating at resonance. In establishing a standard ASTM method for use of an instrument operating on this principle, the effect of three factors inherent in fibers had to be determined. These are (a) shape of fiber cross section. (b) area of cross section, and (c) Young's modulus. This paper is a report of the cooperative test program under ASTM auspices. Results indicated that equipment and procedure used without corrections for the effect of the various factors involved furnish reliable linear density measurements within about 5% of the denier value obtained.