Delft University of Technology
Faculty Mechanical, Maritime and Materials Engineering Transport Technology
A. van Nieuwenhuijzen The stability of pipe conveyors - A numerical investigation into the effect of the troughability of a conveyor belt on the stability of pipe conveyors.
Computer program, Report 2006.TL.7000, Transport Engineering and Logistics.
There are no design standards for pipe conveyors. The absence of these standards causes a low efficiency of the designing process of a pipe conveyor. That's why it is interesting to research the effect of the troughability on the stability of the pipe. The stability of the pipe is defined as the ability of the belt to keep the pipe shape. This research is done with two models in Ansys, the trough model and the pipe model. Ansys is a finite element software package. The trough model has been built according to the standard ISO 703-1 [ISO 703-1, 1999] to express the troughability of the belt in one parameter. The pipe model has been used to investigate the effect of the troughability on the stability of the pipe.
For the numerical tests, an st2400 belt from Taeryuk has been modelled. The inner layer of the modelled belt, which consists of steel cables and rubber between these cables, has been modelled as one layer, which consists of one material. The material properties of this layer have been calculated with formulas from W.D. Callister Jr Materials science and engineering - An introduction [5th ed., New York, John Wiley & Sons, ISBN 0-471-32013-7 (1999)]. All the modelled layers consist of linear elastic materials, but not every layer consists of the same material. Therefore, the material properties differ sometimes per layer depending on the layer's material.
The trough model consists of a part of the belt with a length of 150mm. This model is loaded under his own weight. The maximum deflection (F) has been determined with this model for different values for the Young's modulus of the inner layer of the belt in the x-direction (Ex layer4). The x-direction is the same direction as the direction of the width of the belt. The ratio F/Wbelt has been determined with the help of these results, in which Wbelt is the width of the belt. The ratio F/Wbelt represents the troughability of the belt.
The pipe model is a part of the pipe conveyor between two idlers. The forces in this model are the gravity, the tensile force and the initial stresses in the belt, which are caused by the fact that the belt is formed to a pipe and pre-stressed. There is no material inside the pipe. With this model, the displacements of some nodes have been determined for different values for Ex layer4 to determine the influence of the troughability of the belt on the stability of the pipe. Based on the results of the numerical analysis it could be concluded that the pipe is stable when the troughability (F/Wbelt) is greater than 0.12 and smaller than 0.36 because, when the troughability becomes smaller than 0.12, a gap is arising between both sides of the belt. When the troughability becomes greater than 0.36, the belt looses contact with the upper three rollers. This applies for an st2400 pipe conveyor belt from Taeryuk with a diameter of the pipe equal to 0.49m and the length between two idlers equal to 2m.
Some assumptions were made to model the belt and the pipe conveyor. These assumptions must be verified by a practical, physical test formation during further research, by which the same displacement can be measured as the displacement, which have been determined by the trough and pipe model. Other recommendations are to determine the influence of other parameters than the troughability on the stability of the pipe and to make an advanced version of the pipe model a model, which takes the conveyed material into account or a model with more supports.
Reports on Transport Engineering and Logistics (in Dutch)
