[INNOVATIONS] Bringing reality to WIRE ROPE TESTING BY PATRICIA GLYNN
What if there was a wire rope bending fatigue test machine which could, for example, more accurately reproduce the conditions typically encountered on a crane? And what if this same machine could also supply all the information normally gathered from eleven separate trials in just one testing cycle?
For Roland Verreet, owner of Aachen, Germany’s Wire Rope Technology, a steel wire rope failure analysis corporation, a testing machine should, at the very least, “tell you if you have a good rope or bad one.” Yet much of the existing conventional equipment, he observes, isn’t even meeting this very reasonable expectation. It is, he asserts, a very disconcerting problem. Fortunately, he has a solution – and his answer,
he promises, is poised to upend traditional testing as we know it. T e importance of testing wire ropes can’t be
emphasized enough. Every rope, after being subjected to corrosion, abrasion, and fatigue, will eventually fail. And so the better and more sophisticated your testing equipment, the more likely you’ll be able to predict where and when the inevitable failure will occur. T is, in turn, can lead to signifi cant savings in terms of time, money, and, most importantly, lives. What is perhaps Verreet’s biggest criticism of
conventional testing machinery involves the number of testing sheaves normally included. “With the typical machine, there is usually only one test sheave. Given this, you may actually never fi nd out if you’re working with a bad rope,” he cautions, “because unfortunately the sole test sheave will milk any looseness from the test zone. T is means that if the rope was, for instance, manufactured with an incorrect backtwist, an issue that on a crane would lend to problems over time, the length diff erences created during manufacture will be milked out of the test zone and the test machine will end up analyzing a good rope.”
A typical crane will, in all likelihood, feature multiple sheaves. If an issue does arise then one
Roland Verreet, Wire Rope Technology
sheave will push any length diff erences between the rope elements, or as Verreet’s suggests, “milk the looseness,” onward to a fellow sheave. T e fellow sheave will milk it back, and the looseness thus remains in the reeving system., T e rope,” Verreet points out, “will deteriorate prematurely.” Verreet began to think of how he might better
reproduce reality during the testing phase so as to increase the probability of exposing faults. Eventually, after calling upon his nearly forty years worth of experience and knowledge, it came to him: “Ideas like this come in the fl ash of a second,” he says. He designed a bending fatigue machine incorporating fi ve separate sheaves. “T e rope is subjected to fi ve times as many
bending cycles,” remarks Verreet. “One section of the
WIRE ROPE EXCHANGE
JANUARY-FEBRUARY 2013
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