Krzysztof Talaśka

Contact Problems between the Hub and the Shaft with a Four-Angular Shape of Cross-Section for Different Angular Positions

The works [1, 2] present the values of the force and moment of friction needed to disassemble the axisymmetric connection with oval and three-angular shape of cross-section of the shaft. These works additionally show the variable values of the Mises stresses and contact pressures. This paper presents research which is a continuation of the research program on the evaluation of the influence of cross-section deviations, radial deviations, and their compilations on the value of the contact area in the connection. The limited contact area has a decisive impact on functional and operational parameters of the connection. Point contact between the shaft and the hole is the reason of the reduction of load transmission. The paper concerns the connection between the shaft with four-angular shape of cross-section with the deviation Tw = 13 μm and the hub with the nominal roudness. The authors have proved the occurrence of variable values of the force and moment of friction during disassembling of the connection. The authors have also showed the occurrence of variable values of the reduced stresses and contact pressures.

Perforacja pasów do transportu podciśnieniowego - metody, materiały oraz problemy

The analysis of suitable perforation methods for polymer composites belts with regard to modern material trends in manufacturing the conveyor and timing belts for the vacuum transport was presented. Authors also discussed problems, which occurs during belt perforation and specified the research area, which will help to develop the production process of perforated belts.

Static Compression Tests of Concentrated Crystallized Carbon Dioxide

This paper presents the results of static compression tests of concentrated crystallized carbon dioxide. The test results obtained under this research describe the relationship between the compressive stress and strain allowing to estimate the proportionality ratio, limit stress and critical stress values. Special test methods were used due to low temperature of crystallized carbon dioxide (minus 78.5°C) and its sublimation under standard testing conditions. The results of the mechanical properties of agglomerated CO2 were compared with the mechanical properties of other known materials. This allowed us to derive assumptions, which can become the starting point of the process to build a mathematical model describing the dry ice compaction and granulation processes.

Experimental research of round welded drive belts

Butt welding using the hot plate method is one of the stages of the production of tension belts with a circular cross-section. They are usually made of elastomeric thermoplastics, most often polyurethane [1]. The growing demand for these elements has influenced the need to automate their production. Hence the idea of designing a device to connect them, allowing to automate manual hotplate welding. The aim of these activities is not only to improve production efficiency, but also to obtain a consistent, high quality belts. The research concerned the butt welding by means of a hot plate of industrial tension belts with circular crosssection, made of polyurethane. One of the research stages was conducting welding tests in laboratory conditions. In order to be able to evaluate the correctness of the connection, certain weld quality control procedures should be applied and its significant mechanical parameters, e.g. the tensile strength limit, should be measured. These results will be referred to the strength of the native material. Due to the lack of precise data on these materials, their thermomechanical properties should be investigated. The obtained material solids will also be used to develop a physical model of the butt welding process, using a hot plate, at further research stages. In the literature, a number of works on butt welding using the hot plate method can be found. Welding tests were carried out, among others, of belts made of the same material, of various materials and reinforced with fibers or powders of other material. Typically, relatively rigid materials were tested under normal ambient conditions, e.g. polycarbonate (PC) [7,9,13], polymethylene methacrylate (PMMA) [8, 9], acrylonitrile-butadiene-styrene (ABS) copolymer [8], polyethylene (PE) [11] or polypropylene (PP) [10]. When welding thermoplastic elastomers, data on material properties and parameters of the welding process are vague and insufficient for analysis.

Butt Welding of Round Drive Belts

Abstract The on-going rapid development of industry encourages development of new production technologies and designing of machines that use inventive mechanical engineering solutions, a big demand for parts of such machines being a natural consequence. Polymeric power transmission belts are a good example of that. This paper proposes an improvement in the process of production of such belting. Their production includes cutting to length and splicing of elastic round belts to obtain endless belts of the specified length. This is the key phase of the whole production process. A number of splicing methods are available using different physical phenomena. One of them is butt welding technique. In this process heat is applied on the material through an additional heating element called the heat platen. The effect depends on several factors, including preparation of the work pieces. Due to its characteristics the process is often carried out by hand. The need for automated manufacturing was created by important factors associated with manufacturing on an industrial scale: cost, time and quality. The proposed butt welding machine, complete with a control system is an answer to this need. The practical benefits include improved repeatability of splices, time savings and less work load for the operator.

Concept of the hexa-quad bimorph walking robot and the design of its prototype

Abstract Present-day walking robots can increasingly successfully execute locomotive as well as manipulative functions, which leads to their expansion into more and more applications. This article presents the design of a hexa-quad bimorph walking robot with the ability to move at a relatively high speed in difficult terrain. It also has manipulation capabilities both at a standstill and in motion. This feature of the robot is made possible by the ability to easily change the configuration from six-legged to four-legged by elevating the front segment of its body. Presented prototype will be used in further research to develop the hexa-quad bimorph walking robot.

Dry Ice Compaction in Piston Extrusion Process

Abstract The article presents the results of research on the effect of extrusion tube geometry on the axial force being the key parameter of the dry ice piston extrusion process. The tests were carried out with the experimental set-up based on a cylindrical extrusion tube used alone and supplemented with reducer (orifice). The focus of the experiments was to determine the effect of compression tube reducer on the value of the force of resistance FOP in the dry ice compression process. Its value can subsequently be used as the basis for establishing guidelines for designing and building machines for compression and pelletizing of dry ice.

Recognition of Seat Elements during Production through Image Processing

The primary aim of the research, whose results are presented in this article, was to investigate the process of visual identification of objects. The objects recognised under this research were passenger seats for mass transit applications. The system presented in this paper is intended to be incorporated in the production process control system. The problem under analysis is based on the need to recognise (identify) an object located in the process area of the machine before proceeding with the process. Neural network was chosen as the adaptive element due to a high degree of similarity between the semi-products. The function of the network was to check if correct element had been fed. The input data fed to the network was the information from processing the photo images of these elements. The results of research as presented in this article are based on a limited set of elements and present the method used for solving the task of identification.

Geometric Indicators of Flexible Slice Lip

The paper is thematically connected with paper making machines. This type of the machine is equipped with a head which has a flexible slice lip for skimming the pulp applied to produce the paper. The definition of geometric features of the slice lip is a key issue. The slice lip should be made of material which is resistant to external factors, and designers want to obtain a high flexibility of this element. It is possible to get a high flexibility by forming a proper shape of the slice lip. The paper presents the proposal of dimensionless geometric indicators which combine basic geometric parameters of the slice lip. These indicators are the following: indicator of the cross-section, indicator of the length and indicator of the length of the transverse notch. FEM strength analyses were done – the aim of these analyses was the determination of the stress state and maximum deflection of the slice lip. The authors have analysed the slice lip with holes for mounting the actuators and the slice lip and with transverse notches for increasing its flexibility. The results were presented in the form of graphs.

The Effect of Magnetic Field on Magnetorheological Composites - Artificial Neural Network Based Modelling and Experiments

Looking for new applications of the available materials, such as magnetorheological elastomers (MERs) is an important element of machine design process. To this end it is necessary to determine their fundamental mechanical properties, including Young’s modulus and shear modulus. These properties are determined experimentally by testing the material in compression, tension and shear. In the case of the analysed group of materials the above-mentioned constants depend, inter alia, on the parameters of magnetic field acting on them. Therefore, it is necessary to determine the character and the extent of variation of the mechanical properties as a function of the physical constants characterising the active magnetic field, namely magnetic flux and magnetic intensity (field strength).This paper presents the results of static compression tests carried out on magnetorheological elastomers. The parameters measured during the static compression test were force and displacement at a pre-set magnetic flux. The maximum strength of the induced magnetic field was limited by the design parameters of the test set-up. In order to determine the behaviour of the material at greater values of magnetic strength and flux the properties of a real material were modelled with a neural network. The simulation was carried out using a simple, one-layer neural network. The chosen network training approach was error backpropagation. This approach enables approximation and predicting of changes of the properties of the tested material. The output results will enable deriving an analytical model of the tested MREs.