The Tensile Behavior of Woven Fabrics at Low and High Strain Rates

Abstract

Measurements of the breaking load of woven nylon and Dacron tapes at low and high strain rates showed that the tape strength is reduced at high pick densities and at a particular low pick density; the former was shown to be related to the high level of frictional restraints in the closely woven fabrics, while the latter is associated with the unique geometrical con figuration of the yarn filaments in the particular structure. The effect of various finishing treatments on the strength and the efficiency of translation of yarn strength to fabric strength was studied. The strength of the tapes is greater at high strain rates than at low strain rates for both materials. It was shown that the tapes are very efficient structures (>90%) under all test conditions. For medium pick densities. the efficiency approaches 100% and, under these circumstances, the effect of finishing treatments is minimized. In general, however, the loomstate tapes are strongest, with scouring causing a slight loss in strength, which is almost com pletely restored on treatment with silicone finish. Particular care is needed to carry out tensile tests on tapes at high strain rates, and a method was evolved for testing deliberately weakened specimens in order to avoid jaw breaks. In addition, a new variable radius-of-curvature capstan jaw was developed, which permits the attachment of tapes to other members such that the full potential strength of the tape is realized. It is suggested that a practical routine fastening system could be developed on the basis of the jaw design.