Dariusz Mazurkiewicz

Problems of numerical simulation of stress and strain in the area of the adhesive-bonded joint of a conveyor belt

Belt conveyors are commonly used in-factory transportation devices built of sections of belt (e.g., a fabric-rubber belt) bonded into a continuous loop. Conveyor belt joints are exposed to substantial dynamic loads during the long time of their operation. Taking into account the fact that ensuring a high durability of conveyor belt joints is tantamount to guaranteeing their reliable operation and that the results of research conducted so far fail to provide unambiguous solutions to a number of problems that emerge in this case, it is advisable that advanced studies using computer techniques should be conducted within this area. Of particular help in the search for new structures and optimum methods for joining conveyor belt sections is finite element analysis, which, however, entails a number of problems. This paper describes the circumstances of occurrence of these problems and potential solutions to them. One important problem in FEM modeling is appropriate definition of the models of the analyzed materials. In the case of conveyor belt adhesive-bonded joints composed of rubber and a gum rubber adhesive, the analyses found in the literature, as a general rule, assume the hyperelastic material model based on the Mooney-Rivlin law, which, however, is a fairly arbitrary choice made without verification against actual strength test data. Rubber is a unique material, capable of very large deformations, by virtue of which it is counted among hyperelastic materials. Such materials require appropriate constitutive models and a reliable choice thereof in each particular case. Adequately precise modeling of the behavior of rubber materials still remains an open question. However, access to strength test data makes it possible to check experimentally which of the available theoretical models best reproduce the behavior of the modeled material. For that purpose, the available hyperelastic material models were tested separately for each constituent rubber material of the analyzed conveyor belt adhesive joint. The models were assessed with regard to the degree of their conformity with experimental data by analyzing the behavior of the hyperelastic material in a given case based on the constructed reaction curves using selected strain energy potentials for the available test data.

Problems of identification of strength properties of rubber materials for purposes of numerical analysis: a review

Proper selection of elements of an industrial-grade adhesive joint consisting of various types of rubber materials, supported by a detailed analysis of the phenomena occurring within the joint, especially with respect to fatigue performance, is still a very difficult and largely unresolved issue. Only single studies using FEM numerical modelling have made attempts at assessing and analyzing the phenomena occurring within the joining area of a rubber conveyor belt. This has been caused by a number of problems that have made obtaining reliable and repeatable results impossible, including the problem of defining appropriate material models for the rubbers of the individual layers of the belt and the joint, which introduce strong non-linear effects into the calculations. Rubber as an adhesive base and a construction material is unique, and its properties can be quite diverse dependent on its composition, content of additives, etc. A vulcanized rubber composition, for instance, consists of one or more rubbers and different types of additives which shape its future properties. That is why solution of the problem of identification of the strength properties of this type of materials for developing an adequate numerical model of an adhesive joint is an important issue from the point of view of industrial application of this method of bonding rubber materials; and especially so that expertise in proper use of appropriate adhesives and appropriate joining parameters is indispensable for obtaining optimal properties and maintenance characteristics of the joint. A typical error in preparing material models of rubber is that strength tests for determining stresses and strains are conducted with reference to the initial value of a specimens cross-section. A large, unanalyzed reduction in the area of the specimen during a strength test has a significant effect on the precision of a FEM model of the analyzed structure. This article analyzes this problem with regard to the modelling of adhesive bonding of rubber materials with a rubber adhesive by presenting a mode of action to be adopted in identifying the strength characteristics of the analyzed materials which eliminates the imprecision of the FEM model.

Binary Linear Programming as a Decision-Making Aid for Water Intake Operators

The cost of energy consumed in the course of pumping water from its sources constitutes a considerable share of the total operating costs borne by a water company. In order to optimize the operation of a water pumping station, it is essential to devise an appropriate pumps schedule. The aim of the work was to develop a smart tool which would facilitate decision-making by the operator of a water intake, including a group of wells, supplying actual municipal waterworks. The tool creates a real-time schedule for wells and pumps integrated with them, which constitutes a basis for a final decision made by the operator, related to the degree and period of their usage. The main criterion of facilitating the decision-making pertained to achieving the minimum energy consumption during pumping water from a well to a reservoir tank, while simultaneously keeping all the wells on full stand-by. The schedule was prepared by means of binary linear programming. In this method, both the function of the goal and the limiting functions are linear, whereas the particular variables belong to the set {0,1}.

Application of a Multidimensional Scaling Method to Identify the Factors Influencing on Reliability of Deep Wells

Elements of the water distribution systems (WDS) as removable objects can be repaired or replaced, however their failures are difficult for analysis. The impact of WDS failures can be reduced if preventive actions are taken based on their potential of occurrences or if a failure occurs and is detected within a minimum period of time after its occurrence. This requires the development of a forensic system for WDS failures. This is why in this paper we will present an analysis of reliability data from a water supply sources consisting of deep wells taking into consideration additional, potential failure reasons. The aim of the work was also application possibility analysis of a multidimensional scaling method to identify the factors influencing on reliability of deep wells.

Intelligent Systems of Forecasting the Failure of Machinery Park and Supporting Fulfilment of Orders of Spare Parts

The article presents the possibility of forecasting failures of machinery park using IIOT (Industrial Internet of Things) that supports the range of activities concerning the collection of data using solutions that, by means of time series analysis and dynamic adjustment of the individual models, will allow to generate prognosis for failures of machinery park. Moreover, the use of the generated prognosis to control the storage of replacement parts and to support the area of orders fulfilment was proposed.