Wire Rope Fatigue Life Calculation

But it is essentially a collection of small filaments wound around each other in a manner that largely retains its shape when bent crushed and or tensioned.

Wire rope fatigue life calculation.

Calculation and to demonstrate the potential and limitations of the forecasting procedure. Feyrer from the university of stuttgart has summed up their findings in a formula which allows to predict the service life of wire ropes in reeving systems with sufficient accuracy. In short the rope s service life can be increased from 40 to 76 5 units a 91 increase by operating on a sheave that is only 71 2 larger in diameter. It is a system for significantly increasing the strength and flexibility of steel wire and.

Out a vast number of wire rope bending fatigue tests. If the same rope works over a sheave with a d d ratio of 55 1 271 2 sheave its service life increases to 76 5 units. Wire rope is also known by many other names such as. To determine the extension of fatigue life for a 3 4 wire rope using a 22 5 diameter sheave versus a 12 diameter sheave.

Subsequently the fatigue life of wire rope is calculated by using the linear cumulative damage theory of fatigue. Feyrer from the university of stuttgart has summed up their findingsin a formula which allows to predict the service life of wire ropes in reeving systems with sufficient accuracy. Part three empirical assessment of steel wire rope service life using bending fatigue calculation. They examined the effectof the essential factors of influenceon the service life of the rope.

Wire multi strand wire flexible wire cable cord steelcord etc. As these are accepted as a fixed percentage it is ignored in the counting. As the fatigue cycle counter described is based around empirical setting of limits the fixed values of d d ratio means it is ignored in this. As a first step an improved grey prediction model is established to predict the reliability life data of wire rope under small sample condition.

Calculating the number of sustainable bending cycles even the inventor of the wire rope oberbergrat albert from clausthal zellerfeld carried out fatigue tests with wire ropes to compare the service lives of different rope designs. The wire rope fatigue test rig is established and the experimental value of the fatigue life of wire rope is compared with the theoretical calculation value. Typical external fatigue breaks are visible on the outside of the wire rope where the crown of the strand is in contact with the sheaves drums and other contact points on the crane. Ratio b 22 5 sheave diameter 3 4 wire rope diameter 30 ratio b 12 sheave diameter 3 4 wire rope diameter 16.

The feyrer formula reads lg n b. In this paper the fatigue life prediction method of wire rope based on grey theory will be used to predict the fatigue life of wire rope under the condition of small sample whole rope test data.