PSI - Issue 19

692 R.B. Kalombo et al. / Procedia Structural Integrity 19 (2019) 688–697 Author name / Structural Integrity Procedia 00 (2019) 000 – 000 . When the cable is vibrated at smaller bending amplitudes, wires would stick together and the cable would behave as a solid rod, increasing the flexural stiffness to its maximum. Some approaches to calculate the value of which take into account the stick-slip between wires and hence the dynamic bending stress can be found in literature (Papailiou 1995 and 1997). 3. Materials and experimental procedure Two cables were tested for this study, namely Orchid and 838 MCM, made of pure aluminium 1350 and 1120, respectively. The cables made of these kinds of aluminium are called All Aluminium Cable Orchid (AAC Orchid) and All Aluminium Alloy Cable 823 MCM, respectively. Each cable has 37 strands of aluminium, as shown in Table 2. Table 2. Geometrical and mechanical properties of the two cables 5

Cable type

Cable diameter (mm)

Ultimate Tensile Strength, UTS (kgf)

Number and diameter of strand (mm)

Liner mass (kg/m)

AAC Orchid

23.30 26.53

5143 9705

37x3.33 37x3.79

0.889 1.150

AAAC 823 MCM

Experimental work was carried out at the resonance fatigue bench of the Fatigue and Structural Integrity Laboratory of the University of Brasília. A schematic representation of the three resonance benches can be seen in Figure 2. Each bench is divided into two parts: the active and the passive span with lengths of 40 m and 6.8 m respectively. The active span is limited by two support points which form the centre of the pulley on the fixed block 1 and the suspension clamp mounted on the adjustable block.

Fig. 2. Three fatigue test benches for overhead cables at the University of Brasília: (a) overall three-dimensional view, and (b) side view.

The passive span is used to stretch the cable at the desired tension by means of the hand traction winch. The stretching tension is also adjustable by adding weights at the fixed block 1 side and the measurement is made by the