Laboratory Assessment of ARC Damage in Railway Overhead Contact Lines With a Case Study on Copper-Silver and Low Oxygen Content Copper

Abstract

This is a repository copy of Laboratory assessment of arc damage in railway overhead contact lines with a case study on copper-silver and low oxygen content copper.

BİR OTOMOBİL BRAKET TASARIMININ ANALİZİ ve DEĞERLENDİRMESİ

“…Bu bilgiler ışığında oluşturulan ağ yapısında Node sayısı 852189, Eleman sayısı 547591, ortalama Skewness 0.5, ortalama Aspect ratio 3.45, ortalama Jacobian ratio (MAPDL) 1.09 ve ortalama Element quality ise 0.612 olarak elde edilmiştir. Sunar (Sunar, 2021), yapmış olduğu çalışmada mükemmel bir tetrahedron eleman için Aspect Ratio'nun 1, Jacobian Ratio'nun 1 ve Skewness değerinin ise 0.5 olması gerektiğini paylaşmıştır. Bu ifade üzerine yapılan değerlendirmede mevcut çalışmadaki değerlerde Aspect Ratio değeri haricindeki değerlerin mükemmel seviyede olacağı görülmektedir.…”

A new small sample test configuration for fatigue life estimation of overhead contact wires

“…In order to determine test loads, equivalent pantograph force data from an existing model was used. Strain values in the real span lengths due to the pantograph contact force was used from an existing model 14 and the test loads were selected to create equivalent surface strain same as the real span length.…”

“…Regarding the bending stress in the contact wire due to the contact force, Kim et al 13 highlighted that the uplift displacement was directly related to the bending strain of the contact wire and the contact force was the most important factor in determining its fatigue life. To broaden this knowledge, Sunar 14 conducted research to establish a correlation between contact force and bending stress/strain in the contact wire by using inspection data collected from UK mainline railway equipped with “Series 1” OLE. 15 Combined with FE modelling this showed that depending on the configuration and OLE fittings used the maximum strain in the contact wire could reach the elastic limit of the material when contact force increased from the typical design operating condition of 100 N to a peak of 300 N bringing the potential for permanent plastic deformation.…”

“…On the question of whether other factors exist to initiate fatigue in the contact wire, a small scale study by Massat et al 16 found that defects on the surface of the contact wire due to pantograph friction, electrical arcs and corrosion could cause crack initiation and increase the risk of fatigue failure. Sunar et al 14,17 examined existing contact wires extracted from a mainline and conducted laboratory tests with contact wire samples to determine whether arcs have the potential to initiate fatigue damage in the contact wire. Their results identified defects including voids beneath the surface of the contact wire in areas subject to arcing that significantly reduced total fatigue life.…”

Experimental Investigation on the Arc Damage and Fatigue Crack Initiation Risk of Copper-Silver Contact Wires

“…Some designs use a crack-motor mechanism to oscillate the contact wire sample while others used linear servo motor or hydraulic actuator [9], [10]. However, Sunar et al [11] proposed a new experimental configuration which accommodated a 400mm-length contact wire using a combination of bending and pretension to replicate service conditions found in longer spans. The much shorter length of wire used was an advantage for comparative tests focused on novel wire metallurgy for which only limited supplies existed, and in study of cracks propagating from known sites of surface damage.…”