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1

New challenges and technologies related to aircrafts’ battle damages

Roskowicz M., Smal T., Szrama S.

Scientific Journal of the Military University of Land Forces

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2018

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Vol. 50, No. 2(188)

208--223

EN

The authors of the article present the idea of the maintenance of aircrafts’ battle damages. The aim of the paper is to discuss the issue of the field maintenance of aircrafts. The process of evaluating damages and recommendations regarding verification of airframe structure elements and its equipment damaged by an enemy’s impact has been addressed. The paper demonstrates the changes in dealing with the issue of battle damages of aircrafts, which have occurred over the period of several decades. The new challenges faced by personnel servicing the modern aviation constructions in a contemporary battlefield have been subjected to the evaluation. Concepts regarding the new maintenance methods of an airframe construction of military aircrafts have been outlined.

2

Możliwe straty spowodowane w Polsce wichurami, trąbami powietrznymi i szkwałami

Chmielewski T., Szer J.

Inżynier Budownictwa

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2018

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nr 1

26--31

3

Lamb wave-based monitoring of shear failure of an adhesive lap joint

Rucka M., Wojtczak E., Lachowicz J.

Diagnostyka

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2018

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Vol. 19, No. 4

51--57

EN

The paper presents a study on the elastic wave propagation in adhesive joints of steel plates subjected to tensile loading. A single lap joint was chosen for analysis because of its simplicity and plurality of applications. Experimental investigations consisted of the uniaxial extension of prepared specimens. Force and displacement values were recorded by a testing machine. Simultaneously, guided Lamb waves were excited and signals of their propagation were collected in a number of points by piezoelectric transducers attached to the specimen surface. Further processing of signals allowed to determine some disturbances in gathered data. The continuous wavelet transform revealed discontinuities in force-displacement relations. The Fourier transform showed changes in frequency values of recorded signals. Large disturbances of the root mean square values were also observed. The results of all analyses allowed to conclude that the identification of partial degradation state before the sample destruction was possible.

PL

Artykuł przedstawia badania propagacji fal sprężystych w połączeniach klejonych płyt stalowych poddanych działaniu obciążenia rozciągającego. Pojedyncze złącze zakładkowe zostało wybrane do analizy ze względu na jego prostotę i mnogość zastosowań. Badania eksperymentalne polegały na jednoosiowym rozciąganiu przygotowanych próbek. Wartości siły i przemieszczenia były zapisywane przez maszynę wytrzymałościową. Jednocześnie, wzbudzano fale prowadzone Lamba, a sygnały ich propagacji rejestrowano w kilku punktach za pomocą czujników piezoelektrycznych przymocowanych do powierzchni próbki. Dalsza obróbka sygnałów pozwoliła na wykrycie pewnych zaburzeń w zebranych danych. Ciągła transformacja falkowa ukazała nieciągłości w zależnościach siła-przemieszczenie. Transformacja Fouriera pokazała zmiany w wartościach częstotliwości zarejestrowanych sygnałów. Zaobserwowano także duże skoki wartości średniej kwadratowej. Wyniki przeprowadzonych analiz pozwoliły na sformułowanie wniosku, iż identyfikacja stanu częściowej degradacji przed zniszczeniem próbek była możliwa.

4

Ocena uszkodzeń studni i wpustów ulicznych w Gdańsku

Pszczoła M., Edel R., Górecka E., Papkow I.

Przegląd Komunikacyjny

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2015

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Nr 11

9--13

PL

W niniejszym artykule przedstawiono metodykę badań oraz wyniki oceny uszkodzeń studni i wpustów ulicznych na wytypowanych odcinkach ulic w Gdańsku, charakteryzujących się dużym natężeniem ruchu. Łączna długość ocenionych odcinków ulic wynosiła ponad 10 km. Ocenie poddano ponad 500 urządzeń uzbrojenia inżynieryjnego: studni kanalizacji deszczowej i sanitarnej oraz wpustów ulicznych. Stwierdzono trzy najczęściej występujące rodzaje uszkodzeń analizowanych elementów ulic: zapadnięcie poniżej poziomu sąsiadującej konstrukcji nawierzchni, wyniesienie powyżej poziomu nawierzchni oraz niedopasowanie (wyeksploatowanie) elementów żeliwnych. Zgodnie z Ogólną Specyfikacją Techniczną D-03.02.01 a uszkodzenie studni kanalizacji deszczowej lub sanitarnej występuje, gdy różnica poziomów pomiędzy górną powierzchnią kołnierza żeliwnego lub włazu studni, a górną powierzchnią nawierzchni wynosi > 1,0 cm, natomiast uszkodzenie wpustu ulicznego występuje, gdy różnica poziomów pomiędzy kratą wpustu, a górną powierzchnią nawierzchni wynosi > 1,5 cm. Podczas badań stwierdzono, że kryteria uszkodzeń przyjęte w OST są niewystarczająco precyzyjne, gdyż kierowca odczuwa uszkodzenia studni lub wpustu nie tylko w ich bezpośrednim sąsiedztwie, ale również w dalszej odległości, co wpływa na komfort jazdy. Dlatego zaproponowano zmodyfikowaną metodykę pomiaru uszkodzeń studni i wpustów ulicznych. Według przeprowadzonych badań na wytypowanych odcinkach ulic w Gdańsku stwierdzono, że aż 64% urządzeń uzbrojenia podziemnego ulic nadaje się do renowacji. Warto podkreślić, że stosując metodykę zgodną z OST do renowacji zakwalifikowano by znacznie mniej, bo 35% urządzeń. Najczęstszymi przyczynami uszkodzeń są niewłaściwa regulacja już na etapie budowy lub remontu nawierzchni, złe dopasowanie elementów, niewłaściwie dobrane i zastosowane materiały do regulacji studni i wpustów, np. betony o zbyt małej wytrzymałości, nieodporne na działanie wody i mrozu.

EN

This paper presents the research methodology and the results of the damage assessment of manholes and street inlets on selected sections of streets in Gdansk, characterized by heavy traffic. The total length of the sections assessed during research was over 10 km. More than 500 devices were evaluated: the drainage and sewerage manholes and street inlets. There were found three most common types of damage of the analysed elements: deformation below the pavement surface, the elevation above the pavement surface and the mismatch (exploitation) of the cast. According to the General Technical Specification D-03.02.01 damage of manholes occurs when the difference in level between the upper surface of the collar or cover, and the surface of the pavement is > 1.0 cm, while the damage of street inlet occurs when the difference in levels is > 1.5 cm. It was found during the study that the damage criteria adopted in the OST are far imprecise, as the driver feel uncomfortable not only in the close vicinity of manholes and street outlets, but also at a distance, which affects the driver comfort. Therefore a modified methodology was proposed for measuring the damage of manholes and street inlets. According to research conducted on selected sections of streets in Gdansk was found that as many as 64% of the devices are suitable for renovation. It is worth noting that a methodology consistent with the OST for renovation qualified by much less, because 35% of the devices. The most common causes of damage are inadequate regulation at the stage of construction or repair of roads, poor matching items improperly selected and the materials used to settle manholes and streets inlets, for eg. concrete with too low strength, not resistant to action of water and frost.

5

Kaiser effect observation in reinforced concrete structures and its use for damage assessment

Vidya Sagar R., Raghu Prasad B. K., Singh R. K.

Archives of Civil and Mechanical Engineering

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2015

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Vol. 15, no. 2

548--557

EN

Reinforced concrete (RC) beams of span 3 m were tested under incremental cyclic load at different loading rates and simultaneously during the fracture process in the RC beams acoustic emissions (AE) were recorded. An attempt has been made to study the Kaiser effect as a measure of damage in RC beams. It was observed that RC beams made with high strength concrete under incremental cyclic loading showed an obvious Kaiser effect before the failure load. The results may be useful to study the damage in concrete structures and provide a reference for the application of Kaiser effect in engineering practice.

6

Evaluation of Impact Damages in Composites Based on Fusion of Ultrasonic and Optical Images with Optimized Parameters

Katunin A., Przystałka P., Wronkowicz A.

Machine Dynamics Research

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2014

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Vol. 38, No. 3

33-41

EN

Character of initiation and propagation of impact damages in polymer constructional composites does not allow for unambiguous evaluation of a structure condition basing on observation of its surface only. The developed method is based on wavelet fusion of ultrasonic and optical images with optimization of wavelet parameters, which allows for obtaining of single image with distinguishable internal and external damages. The method was tested experimentally on the composite plates after impact loading with various impact energy and different types of impactors.

7

Estimation of Relative Crack Depth in Composite Beams Using Wavelet Analysis

Katunin A.

Machine Dynamics Research

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2014

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Vol. 38, No. 1

39-46

EN

In this paper the method of crack detection, localization and estimation of its relative depth using wavelet analysis was presented. Basing on obtained results, which were based on the analysis with application of B-spline wavelet the consequences of inappropriate selection of wavelet order for the analysis was shown. In the case when the values of wavelet order were too low the detail coefficients were biased by the inappropriately filtered signal, which cause a significant increase of detail coefficients values in the location of a crack, while when the values of a wavelet order were too high the decrease of values of detail coefficients were observed due to the power losses caused by increased together with the wavelet order the length of effective support of a wavelet.

8

Detection and Localization of Cracks in Composite Beams Using Fractal Dimension-Based Algorithms : a Comparative Study

Katunin A., Serzysko K.

Machine Dynamics Research

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2014

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Vol. 38, No. 2

27-36

EN

In the presented study the possibility of application of algorithms, which based on the estimation of fractal dimension for the problems of damage detection in localization in composite structures was considered. Four algorithms were compared with respect to accuracy of detection and localization of damages in a composite beam and unambiguity of obtained results. Thanks to the low complexity of the computational algorithms, which based on fractal dimension they could be successfully applied in the diagnosing and monitoring real-time systems and even implemented in hardware.

9

Influence of test conditions on modal characteristics of reinforced concrete structures under different damage scenarios

Srinivas V., Sasmal S., Ramanjaneyulu K., Jeyasehar C. A.

Archives of Civil and Mechanical Engineering

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2013

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Vol. 13, no. 4

491--505

EN

In the present work, studies are carried out on experimental modal analysis of reinforced concrete structural members for damage assessment using linear and nonlinear vibration characteristics at different levels of damage. Parameters such as support conditions, type and level of excitation etc. are found to have prominent influence on vibration characteristics. Experimental investigations have been carried out to estimate the influence of these parameters on the vibration characteristics of reinforced concrete structures. Based on the investigations using different excitation mechanisms, it is noted that resolution of modal responses in the case of burst random is much better when compared to true random excitation. The excitation type and force levels are found to have considerable influence on vibration characteristics. It is opined that judicious selection in using the type of excitation, level of excitation force plays important role especially when evaluating the vibration characteristics of reinforced concrete structures for damage assessment.

10

Studies on woollen threads from historical tapestries

Odlyha M., Theodorakopoulos C., Campana R.

Autex Research Journal

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2007

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Vol. 7, no. 1

9--18

EN

Fourier transform (FTIR) attenuated total reflectance (ATR) and second derivative spectroscopy has been used for the first time to evaluate the state of degradation in historical woollen threads from the collections of Flemish tapestries (15th-17th centuries) in the Royal Palace, Madrid, Hampton Court Palace, and museums in Brussels. The work was performed as part of the EC-funded project "Monitoring of Damage in Historic Tapestries", also known as the MODHT project [1]. The overall aim was to develop procedures for recognising tapestries at risk and provide analysis for informing collection care. Prior to the testing of the historical threads, model tapestries were prepared according to traditional techniques of weaving and dyeing. They were then subjected to accelerated light ageing. This paper reports on the part of the MODHT project in which ATR-FTIR was used. It was selected since it is a non-destructive method, and also because it has previously been used to study the oxidation products of cystine in wool and to provide a semi-quantitative assessment of change [2]. Evaluation was conducted on the model tapestries, and the cysteic acid peak was selected as the marker for change, as it showed a systematic change with light ageing. The same marker was used to assess the change in historical threads.

11

Zastosowanie analizy modalnej do detekcji uszkodzenia wiaduktu

Mendrok K.

Diagnostyka

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2006

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nr 2(38)

69-74

PL

W pracy przedstawiono główne problemy eksploatacyjnej analizy modalnej dużych obiektów budownictwa lądowego. Skupiono się na trudnościach związanych ze specyfiką obiektów tj. gabarytami i niekorzystnymi wpływami otoczenia. Opisano badania modalne przeprowadzone na wiadukcie drogowym w celu określenie jego stanu technicznego. Wiadukt ten nie był wcześniej badany więc nie dysponowano modelem dla obiektu w stanie nieuszkodzonym co znacznie utrudniło ocenę stopnia jego uszkodzenia.

EN

In the paper the main problems of the operational modal analysis of large civil engineering objects are presented. Author focused on the difficulties which come from the specificity of the objects, that is the large dimensions, negative influence of the environment. The modal analysis performed on the road viaduct for its damage assessment is described. There are no undamaged model data available, what made the damage assessment particularly difficult.