Calculation of the depth of rope-tightening soft material and analysis of its relationship with the tightening force

To analyze the relationship between the tension force of a rope and the bundled material's indentation, a model of tightening by rope for soft material was designed for testing. By calculating the indentation depth of soft materials from rope stretching displacement, the variation law of the indentation depth of tightening soft materials with different mechanical properties of ropes was analyzed. As the stretching progresses, the more the rope winding turns, and the shallower the indentation depth. The friction coefficient between the soft material and the rope does not significantly affect the theoretical indentation depth. The theoretical indentation depth of high-strength ropes shows a linear variation pattern. The theoretical indentation depth of high-extension ropes is negative. With the theoretical indentation depth of the ordinary rope increasing first and then decreasing, its indentation depth curve shows a parabolic shape. Aromatic polyester rope, cotton chainette thread, and polypropylene rope were used to tighten ethylene-vinyl acetate (EVA) foam and test the indentation depth. The results show that the deformation of the rope is much lower than that of the EVA foam, and the depth of the strangulation is closely related to the tensile displacement and tightening tension. The measured value of the indentation depth is lower than the calculated value, and the greater the stiffness of the rope, the smaller the difference between the measured and calculated indentation depth. The indentation depth method was used to calculate the tightening effect of ropes with high rigidity and has excellent results.