Visual testing of ropes using 3 dimensional model of their geometry

The paper discusses a three-dimensional (3D) laser method which is used to produce an artificial image of the rope surface. The 3D model of the rope surface is created using the method of laser triangulation. In fact the model is a very precise digital three dimensional colour map showing the rope surface. The map is presented in artificial colours. The map shows the area 360 degrees around the entire length of the tested rope. The artificial colours show the rope profile height. The profile height is measured by a laser beam and its reflection. The image as a mathematical model exists in the form of digital representation of the actual geometric dimensions which are visible on the rope surface. Such a mathematical representation allows determination of the basic rope parameters like lay length and diameter. It can also help estimate the degree of rope wear in rope health monitoring. In this article issues related to the measurement of the height profile of the surface of the rope are discussed. Based on tests and analyses of the 3D model also a range of inspection tasks is indicated. The presented model can be used as precise additional diagnostics tool for visual (fibre and wire ropes) and non-destructive magnetic testing (wire ropes only). The data can be stored in a computer for future use and comparisons. This method is universal and can be used not only for wire ropes but for fibre ropes as well. In the simple version with one laser the method can be used only for the rope lay length and diameter measurement.

Author(s): A. Sioma, G. Olszyna and A. Tytko