Dynamic modeling of nylon and polyester double braid line

Abstract

The dynamic stiffness (called the apparent spring constant) and hysteresis of nylon and polyester double braid lines 1-1/2 and 2 inches in diameter are determined in a series of laboratory tests. The experimentally determined apparent spring constant and hysteresis are treated analytically to calculate the viscoelastic parameters of the three-parameter model of a synthetic line. The dynamic behavior of nylon double braid line of 1/2 to 2 inches in diameter are represented by a single equation. The dynamic behavior of 1-1/2 inch and 2 inch diameter polyester double braid line is presented. The apparent spring constant and hysteresis stabilize (i.e., change by less than 10%) after approximately 10,000 cycles of loading. The hysteresis decreases by approximately 30-50% between approximately 100 cycles and 10,000 cycles of loading. The apparent spring constant increases by approximately 20% between approximately 100 and 10,000 cycles of loading.