PSI - Issue 19

R.B. Kalombo et al. / Procedia Structural Integrity 19 (2019) 688–697 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

4

691

Distance from the measurement point of the bending displacement ( Y b ) to the LPC between the cable and the suspension clamp

Every Day Stress EDS (H/w)

89 mm

Bending displacement, Y b

Cable

Suspension clamp

Every Day Stress EDS (H/w)

The last point of contact (LPC) between the cable and the suspension clamp

Fig. 1. Schematic montage of the system cable and suspension clamp showing the measurement point of the bending amplitude and the last point of contact.

Poffenberger-Swart related the bending amplitude peak to peak of the cable measured at the reference distance from the clamp with the stress in the strands of the outer layer diametrically opposite to the last point of contact (LPC). More specifically, the P-S formula can be written as follows: b Y K  = (1) where is the dynamic bending stress amplitude (zero to peak), is the cable´s vertical displacement range (peak to peak), measured at 89 mm from the last point of contact (LPC) between cable and clamp, K represents Poffenberger parameter and is given by: (2) where (MPa) is the Aluminum Young´s modulus, (mm) is the diameter of the outer layer´s wire. stands for the distance on the cable between the LPC between cable and clamp and the vertical displacement measuring point (usually = 89 mm), and (3) with denotes the static cable tension at average ambient temperature during the test period in N. is the flexural stiffness of the cable in N.mm 2 , whose minimum value is: 4 4 64 64 a s min a a s s d d EI n E n E   = + (4) where , , are respectively the number, the individual diameter and Young´s modulus of the wires under investigation and , , represent the same values for steel wires. In this approach, the cable is considered as a bundle of individual wires free to move relatively to each other and the flexural stiffness exhibits its minimum value 2 4( 1 ) px a px E dp K e − = − + p T EI =