Applied Mechanics and Materials Vol. 611

Abstract: The paper deals with the analysis of influence of pipe deviations on in-pipe machine locomotion. In-pipe machine locomotes inside a pipe using the friction difference principle of locomotion. Main task of the machine is inspection of inner pipe wall as the prevention of pipe crack and leaks of transported medium. Pipe systems have deviations of inner pipe wall, which are caused by production process and caused by using of pipe (deformations, sediments, changes from coupling of pipes etc.). These pipe deviations have direct influence on machine locomotion inside the pipe.

Abstract: The article in question concerns the proposal of a pressure vessel for a water heater made of plastic materials. At present, new materials and technologies are coming to the fore where the product price, above all, plays an important role, taking into account the relevant physical and strength properties. The pressure vessels of larger volume (more than 10 litres) water heaters are only manufactured using steel materials under European Union conditions. The proposal considers the use of an alternative material, namely plastic. By optimising the proposal – by the use of plastic materials – it would be possible to achieve a financial economy, since plastic is a good thermal insulating material and does not require enamelling or the use of a cathode protection. There are plastics available on the market which meet the requirements of heat resistance and have a relatively high tensile strength. One of these proposed materials is Noryl GFN1630V which contains 30 % of glass fibre and was chosen as the optimal material. By making strength calculations in the ANSYS programme, water heater pressure vessels were proposed.

Abstract: Proposed paper describes development of CyberGlove II - MechaTE low-cost robotic hand interface intended for future use in virtual and mixed reality robot programming. The main goal is to explore possibilities and gain programing experience in controlling mechanical hands by means of data gloves and its interconnection to virtual reality modeling software. First part of paper describes recent progress in using virtual reality for purposes of intuitive robot programming; second part includes an overview of recent development of mechanical hands construction, as well as currently available data gloves. Last part provides details about CyberGlove – MechaTE interface and its potential for methods of intuitive robot programming in virtual or mixed reality environments.

Abstract: In engineering practice, some of the structural elements take the form of a thin planar plate. For such elements, it is sometimes important to consider dangerous condition of resonance. A structural element cannot operate in the range of resonant frequencies. It is therefore necessary to determine natural frequencies and normal modes of vibration of such structural elements. Parts of the paper are the results of the analysis of natural frequencies and normal modes of vibration using FEM program Cosmos. The subject of the analysis was a thin flat circular plate considered in three modifications, i.e. free thin circular plate without hole, a thin circular plate without hole, clamped on the outer periphery, a thin circular plate with a hole, clamped on the outer and inner circumference. At the same time, Chladni patterns were obtained. They were created using the Matlab system and extraction of the outputs of the Cosmos program.

Abstract: The presented work is focused on the analysis of stress distribution around the graphitic particles in microstructure of ductile cast iron with the spheroidal shape of graphite (SGCI) and grey cast iron with the lamellar shape of graphite (LGCI). The analysis was made with help of the finite element method in the software system ADINA.v.8.6.2. On the basis of the real structure, the finite element method was used for creation of the model which was subsequently used for calculation of the distribution of stress in the material structure. The input data for numerical analysis were obtained on the basis of evaluation of the structure with help of image analysis. The numerical analysis proved that graphitic particles in the matrix cause the accumulation of stress and the distribution of given stress depends on the shape of the graphitic particles.

Abstract: The paper deals with design of robot for puck collecting. Puck collecting is a competition category at RobotChallenge. The aim of this competition is to find and collect pucks with defined color (blue or red) and place them to home position with the same color. The robot has a two-wheeled undercarriage with differentially driven wheels. The robot works as an autonomous system and it has two microcontrollers for parallel controlling of processes. The robot is able to find and recognize the puck and place it to home position defined with the same color. The designed robot Tukebot attended the competition RobotChallenge 2012.

Abstract: In this paper there is presented a possibility to estimate, with a sufficient accuracy, contact forces on idler rollers of hexagonal idler housing in case of the pipe conveyor belt. This prediction is based on values of tension forces that are measured experimentally. The calculated regressive models are able to predict contact forces in individual positions of idler rollers with suitable correctness. The measurements of tension forces were carried out on a static model of a pipe conveyor. This static model is able to simulate real operational conditions of idler rollers, which guide the conveyor belt. In this way it is very simply possible to determine contact force values in the individual positions of idler rollers. Information about contact forces is useful for designers and for users of the conveyor belts, as well.

Abstract: This article focuses on the analysis of stresses within a thin-walled vessel. Focused on rotary symmetrical shell, boundary faults arising at the junction of the cylindrical part of the vessel and its bottom are monitored. The bottom of the vessel is designed in three variants and obtained values of stresses are compared. From the obtained results it is possible to assess which form of the bottom is preferred.

Abstract: The calculation of the stress in the tooth is based on a number of assumptions. Here is calculated so-called comparative stress. This is useful if they are used in calculating the results and findings from research and practice in the determination of any effects that affect the actual teeth stress. The complicated shape of the teeth is the theoretical determination of stress in the teeth difficult. The starting assumption is highly idealized notion of a linear displacement of the tooth for and tooth load is considered as a beam loaded by bending. The paper deals with the problems of stress examining in a dangerous section of the foot tooth with asymmetrical profile. The stress of tooth is solution by finite element method.

Abstract: This article deals with identification and a control design of nonlinear laboratory model Amira DR 300 in a real time. It mentions a mathematical description of the model, its static and dynamical characteristics. Using an experimental method of identification a model has been created, which is suitable for the purpose of simulation testing of non-adaptive as well as adaptive controllers. These were tested as simple adaptive, i.e. non-adaptive controllers, namely in both simulation ways and at a real model control. For the purpose of a non-adaptive control, system parameters were determined by off-line method of the least squares. In an identification part of self-tuning controllers a method of recursive least squares with directional adaptive forgetting factor has been used.