Wire Ropes Under Bending and Tensile Stresses - Wire Ropes: Tension, Endurance, Reliability - page 296

Table 3.19 Optimal rope diameter, constants for equations ( 3.73 )

Constants c 0 for nominal strength R 0 in N/mm 2
1,570

Loading Wire rope

1,770 1,960 2,160

(a) Rope breaking
c 0,sim F, W and S FC 0.0769 0.0760 0.0752 0.0745

WS FC 0.0947 0.0936 0.0927 0.0918

Simple bending F, W and S WRC 0.0694 0.0686 0.0679 0.0672

or WS WRC 0.0854 0.0843 0.0835 0.0827

Fluctuating tension Spiral round 18 9 7 0.0729 0.0720 0.0713 0.0706

and bending strand rope 34 9 7 0.0795 0.0785 0.0777 0.0770

c 0,rev F, W and S FC 0.0662 0.0654 0.0647 0.0641

WS FC 0.0771 0.0762 0.0754 0.0747

Reverse bending F, W and S WRC 0.0590 0.0583 0.0577 0.0572

WS WRC 0.0668 0.0660 0.0654 0.0647

Spiral round 18 9 7 0.0633 0.0626 0.0620 0.0614

strand rope 34 9 7 0.0678 0.0670 0.0663 0.0657

(b) Rope discarding
c 0,sim

F, W and S FC 0.0767 0.0758 0.0750 0.0743

WS FC 0.0860 0.0850 0.0841 0.0833

Simple bending F, W and S WRC 0.0715 0.0707 0.0700 0.0693

or WS WRC 0.0826 0.0817 0.0808 0.0800

Fluctuating tension Spiral round 18 9 7 0.0756 0.0747 0.0739 0.0732

and bending strand rope 34 9 7 0.0824 0.0814 0.0805 0.0798

c 0,rev F, W and S FC 0.0661 0.0654 0.0647 0.0641

WS FC 0.0732 0.0723 0.0716 0.0709

Reverse bending F, W and S WRC 0.0606 0.0599 0.0592 0.0587

WS WRC 0.0647 0.0639 0.0633 0.0627

Spiral round 18 9 7 0.0653 0.0646 0.0639 0.0633

strand rope 34 9 7 0.0699 0.0691 0.0684 0.0678

The constants gi for ropes running in simple bendings over sheaves with
grooves made of steel or cast iron are listed in Table 3.18 . For reverse bendings the
specific discard limiting force S G /d 2 has to be reduced with DS/d 2 = 50 N/mm 2 .
Wire ropes running over grooves made of synthetic material have to be
inspected with magnetic methods, Table 3.5 . There is one exception for ropes in
elevators running over grooves made of synthetic material and over traction
sheaves with V grooves or undercut round grooves with an undercut angle a C 90
the discard number of wire breaks B A30 = 26 for sZ and B A30 = 13 for zZ ropes
can be used.
The rope drives should be designed in such a way that an unsafe condition can
be reliably detected by a high discarding number of wire breaks. If not laid down
by the standards given, the minimum discarding number of wire breaks should be: