Mariusz Żółtowski

Investigations of harbour brick structures by using operational modal analysis

ABSTRACT Historic harbour brick objects are subject to large dynamic loads clearly reflected by generated vibration processes. The vibrations may affect state of serviceability of structures by lowering comfort of persons working there as well as possible reaching the level hazardous to safety of the structures. The effect of vibrations to structure is mainly manifested by additional stresses in a given cross-section, which are summed up with those resulting from static loads. Moreover often occur consequences associated with environmental conditions and fatigue of materials which accelerate destruction of the objects. Therefore the dynamic loads may cause damaging effects in buildings of various structural types or even lead to their catastrofic destruction. Judging the necessity of improving the quality assessment methods of building structures for purposes of estimation of their state as well as safety factors for brick structures (see PN-B- 03002 standard, p.3.1.3 and 4.6), the author of this work undertook an attempt to investigate destruction process of selected building structures by using the method of operational modal analysis.

Vibrations in the Assessment of Construction State

The knowledge of the dynamic state and structure of the system allows to describe its behavior, and allows creating prognosis models of the system behavior in the function of dynamic evolution time, based on the model of the technical state symptoms growth. Most often, however, there are no known equations describing behaviors of the system in the function of dynamic evolution time, which accounts for the need to apply new tools to examine the dynamic state. There is, therefore, the requirement to experimentally verify analytical technical models as the proper one is a model which is verified in practice. An experiment is, therefore, often only an inspiration for further researches leading to the optimization of the construction. In this work presented are chosen problems of machines’ technical state diagnosis with the use of identification and technical diagnostics methods. Relations between methods of dynamic state evaluation and methods of technical state evaluation were indicated. Example modal analysis results illustrate the complexity of projecting dynamic state researches into diagnostic researches of machine state evaluation.

Assessment State of Masonry Components Degradation

The chosen problems of identification the state destruction of wall elements in work were introduced. It was showed on possible relationships between methods of opinion of dynamic state and methods of opinion of destruction the wall elements. Near they utilizations experimental modal analysis they illustrate the complexity the problems and need of optimization of number component measuring the examples - results of investigations.

Truss harbor cranes modal design elements research

Abstract Dockside cranes must meet the relevant strength requirements that provide usefulness and not endanger the safety of their use. The vibration effect on structural safety hazard results from the impact of horizontal forces caused by the transport of goods for loading and transverse forces caused by wind, which can be dangerous for correct functioning. In addition, there are often serious effects of climate-related impacts of the environment, material fatigue, which actuates the degradation state of the object. Dynamic loads may therefor cause random effects that devastate the structures or lead to their catastrophic destruction. Recognizing the need to improve the testing methods of crane structures in order to assess their condition and assess their safety factors - this paper attempts to develop a methodology for testing the degradation of the selected portion of a construction crane - using experimental modal analysis, realized in simulation tests in the Inventor environment as well as at test stand research.

Study of the state a Francis turbine

Abstract This paper presents a methodology to evaluate the technical state of a Francis turbine by shaft rotor dynamic simulation. There are several rotor dynamic criteria that define the technical state of a turbo-machine. To feed the shaft rotor dynamic model this delivers the required information to accomplish the technical assessment. The numerical rotor dynamic model uses as input, the field forces obtained by the fluid-solid interaction analysis undertaken over the blades of the runner. The rotor dynamic numerical simulations allow to determinate the record-in-time of the displacements of any point along the shaft. This information is relevant for diagnosis tasks, because it is possible to decompose it spectrally and to estimate the severity of the vibrations. Comparing the results of the numerical model against those obtained from machines that operates under normal conditions, it is possible to determinate the technical state of the turbo-machine. This allows studying the stability of the turbine working on several operation ranges. A Francis turbine is a very complex machine that involves many physical phenomena of different nature. In this way, the hydraulic input forces needed by the rotor dynamic model should not be assumed but calculated directly from the fluid interaction over the turbine structure.

Estimation of combustion engine technical state by multidimensional analysis using SVD method

The changes of vibration estimators as a result of engine maladjustment, waste, damage or failure are the main idea of vibrodiagnostic investigation. Diagnostic investigations that use vibration to determine the technical state of combustion engines are very difficult. A limited set of proposed methods could have use in diagnostics. This paper presents a validation of research results of the use of the singular value decomposition (SVD) method. The research object is a combustion engine with power 55 kW at 830 rpm, which is feasible to obtain signals generated by vibration, as well as investigate the influence of the engine in the variation of the vibroacoustic data. Using the SVD method is possible to decide which symptom in the observation matrix is the best to recognise the technical state of combustion engines.

A Hydrogenic Electrolyzer for Fuels

Abstract In this work - in view of still decreasing crude oil resources and increasing fuel prices - are presented issues concerning research on development of other, alternative fuel sources including those used in water, land and air transport means. One of them is hydrogen which, while burning, does not produce noxious carbon dioxide but only side effects such as heat and clean water. It is almost true that along with sudden drop of availability and rising price of crude oil many countries face economical paralysis. Any of alternative sources is not capable of supplying even only a basic amount of such energy, not mentioning the whole amount of energy demanded by our civilization. Hydrogen as an independent fuel for internal combustion engines has yet to go a long way to commercialization. to be Co-burning systems (combustion of mixtures)of today used hydrocarbon fuels combined with hydrogen seem closer to this aim. As proved in many investigations the substitution of a part of hydrocarbon fuel by hydrogen enables to make use of beneficial features of both the fuels. One of possible solutions of the problem may be application of an innovative hydrogenic fuel electrolyzer which is presented and evaluated in this paper.

The Reliability Testing of Brick Infrastructure with Operating Modal Analysis / Badanie Niezawodności Infrastruktury Murowej Z Użyciem Operacyjnej Analizy Modalnej

Abstract Modal analysis is widely used in the removal of defects caused by vibration of infrastructure, structure modification, updating the analytical model, or the control of the state and is used to monitor the vibration of structures in the aerospace and civil engineering mechanics from early 1990 began to pay close attention to the use of operational modal analysis (OMA) in a study of the existing building structures. In this case, the vibration exciter platforms, buildings, towers, bridges, etc. to force Operating (ambient). Here we measure only the response of the force generated by the environment. OMA is also very attractive for aerospace and mechanical engineering. This article presents the results of the existing building structure (reinforced concrete wall using operational modal analysis software and used to carry out the LMS and visualization of the results of such research. Streszczenie Analiza modalna jest szeroko stosowana w usuwaniu usterek spowodowanych drganiami infrastruktury, modyfikacją struktury, aktualizacją modelu analitycznego, czy kontrolą stanu, a także wykorzystywana jest do monitorowania wibracji struktur w przemyśle lotniczym i mechanice inżynierii lądowej Od początku 1990 zaczęto zwracać baczną uwagę na wykorzystywanie operacyjnej analizy modalnej (OMA) w badaniu istniejących konstrukcji budowlanych. W tym przypadku wzbudnikiem drgań platformy, budynków, wież, mostów itp. jest wymuszenie eksploatacyjne (otoczenie). Mierzymy tu tylko odpowiedzi układu na wymuszenia generowane przez otoczenie. OMA jest również bardzo atrakcyjna dla przemysłu lotniczego i inżynierii mechanicznej. W tym artykule przedstawiono wyniki badań istniejącej konstrukcji budowlanej (ściana żelbetonowa) z zastosowaniem operacyjnej analizy modalnej i oprogramowaniem LMS służącym do przeprowadzenia i wizualizacji wyników takich badań.

Improvement the systems of exploitation machine/Doskonalenie strategii utrzymania zdatności maszyn

Abstract It this work was talked over chosen and the new problems of exploitation of folded machine engines, helped with methods of technical diagnostics and monitoring the state. This concerns more and more often: the questions perfecting the effectiveness of methods of diagnosing, systems of preventive exchanges, new solutions of software on stage co-ordinating the decision (one - and the multi - dimension), as and the dedicated systems of diagnosing in engineering of diagnostics. Introduced problems of this study finds in processes of destruction of machine engines his reason, concurrent every machine engine near at hand after her producing, until to liquidation. The be shaping the costs of exploitation of machine engines and the possibilities of applying of well-known strategies of exploitation differentiate in this area the variety of organizational workings. The developing technical diagnostics gives to rational exploitation of machine engines the basis in newly created or the perfected diagnostic systems of exploitation. Streszczenie W pracy omówiono wybrane problemy utrzymania zdatności złożonych maszyn, wspomagane metodami diagnostyki technicznej. Dotyczy to zagadnień doskonalących skuteczność metod diagnozowania, nowych rozwiązań oprogramowania na etapie uzgadniania decyzji (jedno- i wielo- wymiarowej), jak i dedykowanych systemów diagnozowania w inżynierii diagnostyki. Przedstawiona problematyka tego opracowania znajduje swoje uzasadnienie w procesach destrukcji maszyn, towarzyszących każdej maszynie po wytworzeniu, aż do jej likwidacji. Kształtowanie się kosztów eksploatacji maszyn i różnorodność działań organizacyjnych w tym obszarze różnicują możliwości stosowania znanych strategii eksploatacji. Rozwijająca się diagnostyka techniczna daje podstawy do racjonalnej eksploatacji maszyn w nowo tworzonych lub doskonalonych diagnostycznych systemach eksploatacji.