Mechanische Eigenschaften von Polyesterfasern bei kurzzeitiger Zugbeanspruchung, 2. Verformungsgeschwindigkeitsabhängige Kraft-Dehnungs-Diagramme von Polyester-Multifilamentgarn

Polyethylene terephthalate (PETP) multifilament yarns with different thermal history were used as testing materials. The stress-strain curves for strain rates from 0.1 up to 100 000%/s show that the maximum tensile force increases and the elongation decreases with increasing strain rate. However, there are differences for yarns with different thermal history. So a free of stress treated yarn shows less change of the maximum tensile force with increasing strain rate than a yarn treated at the same temperature but under stress. The elongation by the maximum tensile force shows the opposite behaviour. With increasing influence of the elongation rate to the force of rupture the ratio of the maximum tensile force and the relevant elongation increases faster. The initial slope (modulus) of the stress-strain curves of the multifilament yarn increases for all futed stresses and temperatures with the strain rate. The local minimum of the modulus curves shifts to higher modulus with increasing strain rate while the position of the minimum as a function of the elongation remains constant.