Bending of helically twisted cables under variable ... - Pfisterer

2.7. The single layer helically twisted cable as a calculation example
The deliberations ons and and equations equations derived derived above above will now be applied to to a a single single layer layer conductor
conductor. The
aluminium/steel aluminium/steel conductor conductor 35/6 35/6 in in acc. with with DIN 48204, 48204, Fig. Fig. 2.19, 2.19, is is used in the example because because it it has
a simple and clear construction – rendering it suitable for “manual” calculations. The conductor data of
interest here are:
− 1 core wire of steel δ = 2.7 mm, ASt A = 5.73 mm 2 = Ad
− 6 layer wires of aluminium δ = 2.7 mm, AAl A = 34.38 mm 2 = 6 Ad
− Lay angle β = 10° (estimation)
− Average layer diameter dm = 5.4 mm = 2 rm
− Coefficient of friction µ = 0.1 (assumption)
− Young’s modulus ESt St = 210 000 N/mm 2 , EAl = 70 000 N/mm 2
Fig. 2.19 Cross-section section of an ACSR conductor 35/6 (see also Fig. 2.7)
Internal conductor state
The question of how far the wire displacement has progressed must first be resolved. This may be
solved using the two equations (2.24) and (2.23):
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