In recent months, we have dealt with the detailed design and manufacturing of our CBOS test machine “TrowiBend 100” for running ropes and have thereby extended our in-house test equipment. The CBOS test machine for cyclic bending determines the resistance to alternate flexing by means of classic bending testing; it is possible to test loads for individual rope strands ranging from 1 kN to 50 kN, as well as ropes of 6 to 20 mm diameter. We also installed an electronic slippage controller that monitors, and, if necessary, corrects the position of the bending zone. Moreover, bending length can be adjusted electronically and is continuously variable.
Background information:
In many traction and load-bearing applications, ropes are bent under load over disks and drums. In this case, they are stressed/ loaded in a combined manner, resulting in phenomena such as local bonding, fibre cracking, abrasive wear, and frictional heat. The rope’s resistance to this damage – known as “resistance to alternate flexing” – significantly affects the rope’s service life. Since stresses/ loads are very complex, this parameter is difficult to quantify analytically and must be found in so-called bending fatigue tests. The dimensionless parameter of bending cycles indicates how often a rope section was bent until it broke or an agreed time of replacement due to wear, and thus specifies the expected service life or replacement state of rope wear under specific load conditions.