Peter Frankovský

Methodology of contact stress analysis of gearwheel by means of experimental photoelasticity.

The subject of this paper is the analysis of contact stresses that occur between the teeth of a gear. The analysis was carried out by means of reflection photoelasticity, which is an experimental method rarely used in this field. Contact stresses assessed in the experiment are compared with values assessed through an analytical calculation while using the Airy stress function or Hertzian relations.

Further Possibilities of Using Software PhotoStress for Separation of Principal Normal Stresses

Further Possibilities of Using Software PhotoStress for Separation of Principal Normal Stresses Software PhotoStress, elaborated in our laboratories allows determination of directions and magnitudes of strains or principal normal stresses in loaded photoelastically coated structural elements. It allows accelerating process of measurement and evaluation of deformations or stresses in point, along line or along curve, respectively. In those entities can be determined directions, and magnitudes of differences and separated principal deformations or stresses on the basis of photography of loaded photoelastically coated objects. In the paper is given procedure for of evaluation of separated principal normal stresses by using of separation methods: method of difference of shear stresses with using separation strain gage and method of oblique incidence.

Application of the harmonic star method in photoelastic separation of principal stresses.

This paper deals with automation of an experiment process by means of photoelasticity on the condition that only information which was previously collected by identification of isochromatic fringes is used. The analysis of this issue pointed to Poissons and Laplaces equations. These equations were solved through the harmonic star method. The automation of an experiment was based on the development of a noncommercial program for processing of data which had been collected during photoelastic measurements. In addition, the program was used for verification of these measurements and comparison of measurement outcomes with results which were gained by the finite element method (FEM). Such a program enabled us to measure stresses in a certain point of the examined surface and, at the same time, separate these stresses, that is, determine the magnitude of individual stresses. A data transfer medium-a camera-was used to transfer the picture of isochromatic fringes directly into a computer. The chosen procedure of solving and evaluating the experiment provided us with reliable outcomes comparable to results gained by FEM.

Influence Gearing Parameters on the Tooth Deformation of Spur Gears

Gear teeth are deformed due to the load. The tooth deformation of spur gears is not constant for all examined teeth of gears. Tooth deformation is depends on the shape of the teeth, on the basic parameters of examined spur gear, such as the number of teeth, module gearing, pressure angle, gearing width, correction and modification of gearing.

Kinematic Analysis of Mechanisms Using MSC Adams

This paper deals with kinematic analysis of a six-member mechanism. The analytical solution is based on the fundamental kinematic relations derived for this mechanism. The program MSC ADAMS was selected for the simulation modeling of mechanism. That program allows comprehensive analysis of this system using a simple modeling.

Analysis of the Fatigue Life of Composite Leaf Springs

The automobile industry has shown an increased interest in the use of composite leaf springs due to their high strength to weight ratio. The introduction of composite materials has made it possible to reduce the weight of the leaf spring without any reduction in load carrying capacity and stiffness. In this paper, the results of research on fatigue life of composite (Glass Fiber Reinforced plastic – GFRP) leaf springs are presented. Composite springs were designed in such a way that they could replace steel springs in a van.

Kinematic Analysis of Crank Rocker Mechanism Using MSC Adams/View

The aim of this article is to develop a functional model of crank rocker mechanism in ADAMS/View software and subsequent complete kinematics analysis hereof. We analyze the movement of the members of the mechanism. The kinematic analysis was performed analytically and graphically. The mechanism has been modeled too and solution was drafted in the program MSC ADAMS/View. The next stage is the simulation with a set of different parameters to obtain its kinematic analysis. Finally, the data gathered in this process is compared and evaluated. Finally, the paper presents the results with graphical representation of parameters such as speed, distance and acceleration.

Implementation of Correction Coefficients Relevant for Photoelastic Coatings into the PhotoStress Software

Optical experimental method PhotoStress is based on the principle of birefringence that occurs on photoelastic coatings on the surface of an object subject to examination. However, photoelastic coating strengthens the examined surface; hence, strains that co-occur in the analysed object exhibit lower values than when no coating is applied. This is the reason for the implementation of relationships for correction coefficients into the PhotoStress software which is now being designed. These coefficients are supposed to eliminate discrepancies in gained values resulting from the impact of stiffness through applied photoelastic coating. Into the PhotoStress software were implemented correction coefficients for plane stress CPS, one-side coated objects under bending stress CB, two-sides coated objects under bending stress CB2, shaft rotation Ct and pressure vessels CN. The following paper includes explanations of particular types of corrections which were implemented into the PhotoStress software.

Distorsion of Isochromatic Fringes in the Process of Stress Measurement in Structural Part by Photoelasticimetry

Abstract In the article we show the possibility of distorting the results of the experiment by photoelasticity path, in case the isochromatic fringe patterns are recorded by the camera. The recording of the color spectrum may be distorted by inappropriate selection of the recording medium, which is reflected by different types of aberrations. Transferring a record to a computer allows you to automate the experiment process, thus saving time to work with isochromatic fringes. As an example, we present the experimental determination of the stresses of the rotor with a symmetrical arm. The analysis was performed using software developed by the authors. This software enables full automation of the experiment process. The rotor is investigated by the method of reflection photoelasticity. The experimental solution is realized as a case of periodically repeating dynamic effects, in which a stroboscopic source of white light is needed. The results of the experiment are compared with the numerical solution and their dependence is represented by diagram.

The Use of Optical Methods in the Analysis of the Areas with Stress Concentration

Abstract Anchoring parts of technical systems are often damaged due to the heavy forces acting on these systems during their operation. For that reason, various modifications are suggested and created on the anchoring screws, which should help to reduce the mechanical stress values in a place of the first load-bearing thread of a female screw. For the determination of stress fields on the surface of a plane model of a threaded joint, two non-contact optical methods were used – conventional transmission photoelasticimetry and modern digital image correlation.