Dynamic Variation Mechanism Of Pre-twisted Wire Holding Force Under Conductor Compression
The grip strength of the preformed armour rod increases synchronously with the tension acting on it, which is mainly due to the unique design of its spiral structure. When the conductor is subjected to tensile stress, the spiral armor rods will undergo microscopic deformation, and the rotation amplitude of the spiral coil will increase, which will correspondingly increase the compressive stress on the contact surface. This synchronous increase manifests as a linear increase in grip strength in engineering practice, ensuring reliable conductor fixation under various operating conditions.
The contact mechanism between armor rods for acsr and the conductor involves the interaction of multiple geometric parameters. The difference between the inner diameter and the outer diameter of the conductor determines the initial compressive stress distribution, while the pitch affects the number of contact points per unit length. When the conductor is under tension, the frictional force generated at these contact points increases simultaneously with the increase in compressive stress, creating a reinforcing effect. According to the principles of elasticity, the deformation of the helix is positively correlated with the applied force. The greater the tension in the wire, the smaller the pitch of the armor rods transmission line helix, and the higher the coefficient of friction.
The surface treatment of the inner wall of armour rod has a significant impact on friction. Sandblasting or abrasion treatment increases microscopic roughness, thereby improving the coefficient of friction with the conductor surface. Under tension, the presence of this microstructure makes the increase in friction more significant, which helps to expand the dynamic range of grip strength. At the same time, the choice of material also directly affects the friction characteristics. Aluminum-clad steel wire and aluminum alloy wire have different stress responses, resulting in differences in the distribution of compressive stress and the coefficient of friction.
