Patrik Šarga

Determination of the Necessary Geometric Parameters of the Specimen in Ring-Core Method

There are several measuring techniques for determining residual stress which can be divided according to the created damage in to the construction in non-destructive, semi-destructive and destructive ones. One of the most common is semi-destructive hole-drilling method. This paper deals about Ring-Core method which is based on the similar principles. Today, there is no standard for the Ring-Core method, thus it is important to consider various influential factors. One of them are the dimensions of specimen. Calibration coefficients are determined by finite element (FE) analysis using the commercial software Solidworks. These coefficients are used for residual stress evaluation by incremental method used in Ring-Core method. The influence of different specimen dimensions on the accuracy of the evaluated residual stresses is considered.

Kinematic Analysis Planar Mechanism of a Pump Using MSC Adams

The aim of the paper is to present the application of MSC Adams/View for kinematic analysis of motion of a pump mechanism. The first section describes the program Adams and its modules Adams/View, work with this module and its basic operation. In the following section there is the kinematics solved using numerical methods. This work deals with the assembly of the models in Adams/View, simulations, plotting of the trajectory of the mechanisms points, and kinematic parameters of mechanism members. The software shows displacement, velocity and acceleration, angular velocity and angular acceleration. Finally, the paper presents the results with graphic representation of parameters such as displacement, velocity and acceleration.

Proposal of Methodology for Determination of Stresses around Groove by Photo Stress Method

The aim of the paper is to propose a new methodology for verifying residual and operational stresses, determined by the drilling method. The newly proposed methodology will be based on the use of optical methods for total surface deformations and stress analysis through optically sensitive material applied to the surface of the object being investigated.

A geometric approach to modeling of four- and five-link planar snake-like robot

The article deals with the issue of use of geometric mechanics tools in modelling nonholonomic systems. The introductory part of the article contains fiber bundle theory that we use at creating mathematical model of nonholonomic locomotion system with undulatory movement. Further the determination of general mathematical model for n-link snake-like robot is presented, where we used nonholonomic constraints. The relation between changes of shape and position variables was expressed using the local connection that was used to analyze and control system movement by vector fields. The effect of links number of snake-like robot on its mathematical model was investigated. The last part of this article consists of detailed description of modeling reconstruction equation for four- and five-link snake-like robot.

Verification of the Geometric Parameters of the Ring-Core Method

The Ring-Core method is a semi-destructive method for residual stress determination inside materials. The evaluation of residual stresses using Ring-Core method requires complex analysis of the geometric parameters. This work deals with the uniformly distributed residual stress components through the material thickness.

Impact Assessment of the Stresses in the Sheet Made by Welding

The article presents determination of residual stresses in the material caused by production processes, concretely by welding manufacturing process. In this article we analyse welding methods and their impact on the formation of residual stresses. Objects used for conducting the experiment were two samples of welded metal plates. Plates are welded by MAG method, in a controlled atmosphere of carbon dioxide gas. Evaluation process of residual stresses on this plates was made by hole-drilling method by the System MTS-3000.

Modern Trends in the Field of Measurement of Residual Stresses Using Hole-Drilling Method

Residual stresses in the constructions have in most cases a negative effect on their overall life. Large numbers of investigations have been carried out to study this phenomenon and its effect on the mechanical characteristics of these constructions or their components. Hole-drilling method is one of the most used methods used for the determination of residual stresses. This method typically uses strain gauges. This article describes options of using optical methods instead of strain gauge in the process of evaluation of residual stresses by hole-drilling method.

Utilisation Possibilities of PhotoStress Method in Determination of Residual Stresses

The presented paper demonstrates the determination of residual stresses by means of PhotoStress® method. The identification was performed on a drilled and subsequently loaded sample of a split ring. Through drilling and subsequent loading of the sample we were able to simulate residual stresses throughout the surface of the split ring. Using the values of residual stresses, a gradient of residual stresses was specified. The 3 mm thick split ring was laser-cut from a non-alloyed fine-grained structural steel sheet suitable for welding, i.e. steel 11 523. It was coated with 3.125 mm thick photoelastic coating PS-1A with fringe constant.

Kinematics Analysis of the Crank Mechanism Conveyor Using MSC Adams

The aim of the thesis is the solution of kinematics analysis model of the conveyor with a crank mechanism. For solution is to use a graphical method for determining the kinematics parameters of the individual members of the mechanism. In part kinematics analysis is also used MSC Adams View program that is designed to address the problems of kinematics and dynamics of systems with more degrees of freedom. This program shows the displacement, velocity and acceleration and angular velocity and angular acceleration of members. Finally, the work presents the results with graphic display of parameters such as displacement, velocity and acceleration. Introductory chapters are devoted to general issues kinematics mechanisms and the following chapters are devoted to a particular model of the conveyor mechanism.

Balancing of Forces in Segments of Axial Bearing by Dynamometers

The Francis turbine in water power plant station is positioned at top and bottom axial hanging bearings. During reparation work the turbine was disassembled and during assembling the adjusting segments in the hanging bearings were released. In the paper are described procedures that are necessary in order to provide correct distribution of axial forces in twelve segments of upper axial hanging bearing by strain-gages applied on elastic pipes positioned under individual bearing segments.