An investigation into the reaction behavior of tubular braids due to internal pressure

Abstract

Braiding has many applications in different industries as an internal pressurized cylinder. In these conditions, a sustainable structure without any wrinkling and unevenness is quite necessary. Using thin wall structures with closed ends and under internal pressures as a braid is addressed in the present study. With the use of a silicon vessel as the core, the braids with different angles and weavings were produced. They were exposed to internal pressure from zero to failure point. All stages of change in the shapes of the samples were recorded by a camera and the pressure–diameter results were extracted in 10 s once. In this research, the authors elaborate on the theory of stress and wrinkling moment created in these braids under internal pressure, and then they develop a new testing method by which they compare the obtained results with the theory. Following that, the relationship between the angle and failure pressure is investigated to determine the best braid angle in braiding used as thin wall structures. In the braid angle of ± 55°, all the forces created in braid due to internal pressure are along with strands direction and the increase in the cylinder diameter of the braid has been completely controlled depending on strands’ elongation. The rate of diameter increase in the angles of less than ± 55° is fast, especially in pressures close to failure pressure. However, in the bigger angles, the elongation or, in other words, the diameter decrease is observed in braiding.