Force Analysis Of Bolted Tension Clamps Under Axial Tension Of Conductor
In transmission line operation, clamp bolted type strain clamp bears the core function of fixing the conductor end and transmitting mechanical loads. Its internal stress state directly affects the safe operation of the line. The following analysis is conducted from the perspective of mechanical principles and structural design.
The direction of the force and the gripping force form the following:
The direction of the force on dead end strain clamp is the axial tension of the conductor. This tensile force is transmitted and balanced through a complex friction system inside the clamp. The corrugated groove of the clamp body and the pressure plate form multiple friction pairs. When the U-bolt is tightened, the conductor undergoes a bending effect within the corrugated groove. This structure disperses the axial tensile force in a single direction into frictional forces on multiple contact surfaces. The cumulative effect of these frictional forces ultimately forms the total grip force of the clamp on the conductor.
Mechanical Logic of Cable Tray Design
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Wave-shaped Structure: The cable trough has obvious bending and undulation sections, increasing the friction area.
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Conductor Deformation: The conductor bends under pressure, changing the direction of local force.
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Utilization of Friction Coefficient: The friction coefficient between the steel clamp and the aluminum strand is 0.25, affecting the gripping force calculation.
Pressure Transmission of Bolt Tightening
The tightening torque of the U-bolt is converted into vertical pressure. This pressure must overcome the stiffness of the conductor itself. The remaining pressure acts on the surface of the aluminum strand, forming transverse compressive stress. The pressure distribution per unit length determines the actual magnitude of the friction force.
Installation Specifications and Mechanical Performance Relationship
The installation method directly affects the axial tensile load-bearing capacity. U-bolts should not be installed on the load-bearing side of the inverted bolted dead end clamp; all bolts must be located on the jumper side. Reverse installation will reduce mechanical strength and may even cause breakage. The radius of curvature at the clamp outlet should not be less than 8 times the conductor diameter. Insufficient curvature will generate additional bending stress. The combined stress consists of the superposition of transverse compressive stress, longitudinal tensile force, and bending stress.
