DIAGNOSTYKA Vol. 16, No. 3 (2015)
Table of contents - SCIENTIFIC PAPERS
Mariusz SZWEDO, Barbara TOMAKA
Pages :

pdf [downloaded 869 times]

Abstract (EN)
Skin tests in allergology are a method of medical diagnosis that attempts to provoke a small, controlled allergic response. Evaluation of the patch test depends on visual assessment so it is not an objective method, because it does concern only skin surface and difficulties like changes in skin pigmentation, atopic skin, black race skin or delayed reaction may occur. Studies with use of thermography confirm that skin surface allergic reaction is strictly connected with temperature increasing at that area so such technique may be the key for impartial evaluation. Carried out tests, also confirmed information from literature review, that to obtain valuable infrared images large intervals between allergens must be kept.

Paweł ZDZIEBKO, Jakub KORTA, Tadeusz UHL
Pages :

pdf [downloaded 541 times]

Abstract (EN)
Multi-material joints are implemented in many fields, including automotive and aerospace in-dustries. Adhesive bonding technique allows for joining components made of different materials, which facilitates the implementation of lightweight materials in multi-material structures. In this study the shear strength of single lap, adhesively bonded joints was examined at room and high temperature (110⁰C). In the paper the influence of elevated temperature on epoxy adhesive joints in multi - materials structures is presented. A sensitivity of shear strength on material type of ad-herents in adhesively bonded joints is considered. Prediction of the state of joints and knowledge on their degradation process are important for structural health monitoring of structures with adhe-sive joints.
For the purposes of research, specimens consisting of adherents made of various materials were used (following were involved: aluminum alloy, CFRP and abrasive resistant steel). Studies have demonstrated, that applied epoxy adhesive considerably weakens at elevated temperature and it was observed that material type of adherents has a large influence on the shear strength of adhe-sively bonded joints.

Pages :

pdf [downloaded 926 times]

Abstract (EN)
This article presents the strength and modal analysis of the rotor model of the Tesla micro-turbine. The calculations were made in order to verify the design of multi-disc turbine’s rotor before production process.  Two commercial solvers were used independently, which are capable to deal with problems of solid state physics – Abaqus and Ansys Mechanical with Workbench software. The comparison of results from two applications aimed at checking solvers’ applicability in the present case. Preliminary analysis was carried out in Abaqus software. The calculations were performed assuming perfect bearing stiffness for different rotation speeds. A more detailed analysis was made in Ansys Mechanical software using structure analysis modules to determine the stresses in the structure which arise as a consequence of rotor’s rotational motion. Subsequently, it was followed up with modal analysis results. Additionally the parameters of selected bearings were determined and modal analysis took into account the stiffness corresponding to individual rolling bearings.

Pages :

pdf [downloaded 897 times]

Abstract (EN)
The paper presents the results of experimental investigations of the ORC system equipped
with the expansion valve simulating microturbine operation. The aim of the research was to verify
the correct functioning of the installation components and to access the technical condition of the
thermal insulation in the heating and cooling mode with regard to the design assumptions. The
research was conducted for different values of medium flow rates. The images were acquired using
the thermal imaging camera FLIR E50, which is equipped with a specialized software. On the
basis of the experimental results, the heat losses have been estimated, together with the places
which were the major source of loss (the so-called thermal bridges). It was shown experimentally
that the application of a thermal imaging camera can constitute a simple and fast thermal
diagnostics method for installations of this type.

Wojciech SAWCZUK
Pages :

pdf [downloaded 862 times]

Abstract (EN)
The article presents a new method for the evaluation of the braking process through analysis of the braking vibration during braking to stop with a permanent the analysis of temporal signals of vibration acceleration in the frequency domain. The problem of research assembled in the article was determined by estimating the braking process one value of the diagnostic parameter of the vibration signal generated by the disc braking level set during braking.

Pages :

pdf [downloaded 892 times]

Abstract (EN)
Concept of fibre spontaneous Raman scattering utilizing for distributed temperature sensing is presented. Chosen approach uses both backscattered Stokes as reference and anti-Stokes as detection signals. The analysis is carried out towards Stokes and anti-Stokes bands temperature dependence. In order to achieve best measurement accuracy influence of maximum modulation frequency on spatial resolution is verified. Analysed technique allows to calculate temperature along the fibre with 5 m space precision and 1°C temperature precision. Simulations involve 200 m standard single mode fibre in temperatures in range < -5°C , 60 °C> with 2x1100 m reference fibre maintained in 22°C.

Pages :

pdf [downloaded 1059 times]

Abstract (EN)
Knowledge of diagnosed object includes issues of design, manufacture and operation of the facility. One of the objectives of production and structural diagnosis is to identify sources of potential threats and thus in this paper will be presented computer tools for trace detection of gears engagement. In this way it is possible to assess the correctness of their cooperation, determine the causes of high stress, and also reduce the number of tests on a real object.
The study contains selected aspects of creating an application used to facilitate the analysis of gears using the finite element method. There was developed software application, plug-in extending the capabilities of ABAQUS, which was written in Python programming language. Libraries available in the ABAQUS package were used to design a graphical interface for a created application as well as to implement the respective functions of performing specific tasks. Thanks to this application it is possible to easily prepare the model for simulation, as well as to display desirable results, including determined traces of gears cooperation.

Wojciech HOMIK, Tomasz KUDASIK
Pages :

pdf [downloaded 913 times]

Abstract (EN)
The article presents the results of experimental research selected parts of the rubber smalldimension
torsional vibration damper. The study aimed to determine the dynamic loads and stress
pattern in the area of the damper hub mounting to a crankshaft of a multicylinder engine. For this
purpose a photoelasticity is used, what allows to distribution of effort of both real parts of
machine and models based on their , made, among others, RP rapid prototyping techniques
(called. Rapid Prototyping) and RT techniques (called. Rapid Tooling), in
particular by casting in silicone molds (VC. Vacuum Casting).
The paper presents the exact process of create models of torsional vibration damper VC
techniques based on real element and the process of coating photoelasticity layer to the model,
what is necessary to carry the analysis out by photoelasticity method on the reflected light. The
results of analysis, determining the hazardous area in terms of stress distribution. In this study is
presented own experiences and verify the suitability of the method and material used for research
photoelastic ity torsional vibration damper.

Pages :

pdf [downloaded 903 times]

Abstract (EN)
The results of long-lasting research into steel cord belt splices strength performed at Wroclaw University of Technology Belt Conveying Laboratory indicate that the quality of splicing procedure greatly affects splice strength. Properly performed splices have strength of up to 100% of the nominal strength of belt, while the strength of improperly performed splices may be 70% or even lower.
Each mistake made during splicing procedure results in decreased splice strength. Varying operating conditions and unstable conveyor operation may lead to exceeding actual strength values of performed splice. This may in turn lead to the splice breaking and bring the conveyor to emergency stop, until the damage is repaired. Such emergency stop results in a financial loss due to high cost not only of resplicing and belt loop restretching, but also of removing spilled material and of complete transportation system downtime. Practical mistakes made during splicing result in inappropriate splice geometry, which decreases splice strength and in extreme cases may lead to premature splice damage.

Bogdan KOZIK, Mariusz SOBOLAK
Pages :

pdf [downloaded 929 times]

Abstract (EN)
One of the phases of existence of machinery according to [5], is among others, constructing. The aim of constructional diagnostics used in this case is to identify sources of potential risks.
In a dual-path gear transmission power is transferred by two parallel paths. Due to backlash and precision of making the whole gearing, the power is not transferred evenly along both paths. It creates potential risk which makes it necessary to create such gearing with higher module. This in turn causes an increase in dimensions and weight of the gearing. The paper presents a technical solution that allows to delete backlash on teeth on all stages of the gear transmission and thus increase the uniformity of power distribution into two paths. The solution consists in applying an intermediary split shaft whose parts can be exactly positioned angularly in relation to each other in the process of assembling the gear transmission.

Pages :

pdf [downloaded 936 times]

Abstract (EN)
Designing and manufacturing of aeronautic bevel gearboxes is a complicated and time-consuming process. This is due to the high quality requirements to the aviation industry products and the complex kinematic of the machining process. So far, in practice, this process has required a series of research and prototypes testing. The development, has been made in the field of Computer Aided Design systems, allows increasing use in design process and carry out the necessary research in the CAD environment. This approach simplifies and accelerates the aeronautic bevel gearboxes design process.
The study presents process of gears solid models generating and carrying out simulate of cooperation bevel gearbox in the CAD environment. Solid models has been prepared by the solid machining simulation, while the performed analyzes are used to determine temporary tooth bearings, summary tooth bearing and motion graphs.

Pages :

pdf [downloaded 919 times]

Abstract (EN)
The article discusses about the design of a combined exhaust gas heat exchanger with muffler. The first stage deals with the calculation of the exhaust gas heat exchanger according to the required parameters. The next step addresses the structural design of the exhaust gas heat exchanger according to the parameters of the calculation. Subsequently creation a 3D model, which will be used for the simulation of flow of the working substance in the heat exchanger and heat transfer simulation of the media. The simulations are solved in a 3D simulation program COMSOL Multiphysics 5.0. Further solves the structural design of muffler, which will form a part of the exhaust gas heat exchanger. Subsequently execution of the measurements on the real model of the combined exhaust gas heat exchanger to verify the accuracy of calculations, simulations and structural designs.

Janusz Zachwieja
Pages :

pdf [downloaded 931 times]

Abstract (EN)
The rotors can be balanced using two different methods: a modal method and an influence coefficient method. Until recently, it was generally viewed that the former method can be used for balancing rigid rotors, whereas the latter method for balancing flexible rotors. Nowadays, the difference in classification of rotors and the approach to balancing have changed. The study presents general differences between the two balancing methods and compares the efficiency of balancing the flexible rotor using the modal method and the influence coefficient method.