As a key component of high-voltage power lines, aluminium clad steel reinforced (ACSR) conductors must have adequate mechanical properties that ensure running safety. This paper presents the results of experimental and theoretical analysis of spiral stranded conductors that consist of a core with two layers of steel wires and three layers of aluminium wires. Tests were performed using two ACSR conductors of the same type, one new and the other 40-year-old, used for a 220 kV power lines. In service, the conductors can be subjected to additional stresses, which may lead to accelerated deterioration and premature failure. In order to provide reliable results, the tests were performed in similar conditions and using the same equipment for both strands. Comparison of results highlighted the influence of the service time on the mechanical properties.On the other hand, the degradation was decisively influenced by the position of the layer. The mechanical properties of the aged conductor are adequate even after 40 years in service. The most advanced degradations are near the clamping area, therefore intensive inspection and maintenance are recommended.
The maximum values of normal and shear stresses are the basic parameters which influence directly the initiation and propagation of multiaxial fatigue cracks.Based on the above, the first part of the paper presents an analysis of principal stresses (normal and shear) in case of symmetrical tension-compression loadings with superimposed phase-shifted symmetrical torsion cycles. The influence of stress amplitude ratio and phase shift on the maximum (normal and shear) stresses and on the directions of the planes along which these act is analyzed and graphically represented using stress hodographs.The second part of the paper highlights the possibility of using the maximum value of the normal or shear stress as base parameter for durability studies under multiaxial fatigue, based on existing experimental data. The mentioned data is correlated with the results of an original experimental program carried out by the authors on 41Cr4 steel and conclusions are formulated with regard to the role of maximum shear stress in life-time calculation.
Aluminium clad steel reinforced cables are widely used in long distance electrical energy transport. Under the influence of weather conditions, the conductors are subjected to additional stress, which may lead to accelerated deterioration and premature breakage. This phenomenon depends much on contact mechanics. Due to the rough geometry of real mechanical surfaces, the elastic-plastic contact between bodies occurs at several points simultaneously. The contact between wires or between the wires and the suspension clamp, which is regarded as a critical location, changes the mechanical properties of the conductor with the emergence and development of contact indents. In order to understand the development of the indents ant their influence in the properties of the wires, indentation, tensile and fatigue tests were performed on wires taken from a steel-aluminium conductor. The problem of normal contact when plastic deformations are much higher than the elastic ones is extremely complex. The convex profile of the wires brings additional complications. Specific strain intensity is proportional to the depth of penetration. Experimental researches have shown that the shape and size of the indents occurred at the contact points have a significant influence on the tensile strength and lifetime of the conductors and local deformations determine certain features of fatigue crack initiation and propagation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.