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Tytuł:
Survey of modern trends in analysis of continuum damage mechanics
Autorzy:
Ambroziak, A.
Kłosowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/1933193.pdf
Data publikacji:
2006
Wydawca:
Politechnika Gdańska
Tematy:
continuum damage mechanics
ductile damage
fatigue damage
viscoplasticity
Opis:
A brief review of the damage mechanics literature is given. As this area of scientific research is very modern, the authors have restricted themselves to about 100 most impor-tant books and papers. Basic equations to introduce the isotropic model in the framework of thermodynamics are given in a form easily applicable in numerical symulations.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2006, 10, 4; 437-454
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of continuous damage deactivation on yield and failure surfaces
Autorzy:
Cegielski, M.
Ganczarski, A.
Powiązania:
https://bibliotekanauki.pl/articles/387329.pdf
Data publikacji:
2007
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
damage
damage deactivation
failure
Opis:
This article deals with the modeling of the continuous damage deactivation affected yield surfaces of copper and failure surfaces of mortar, from the viewpoint of continuum damage mechanics. The concept of damage deactivation is adapted to Tresca-Guest and Huber-Mises surfaces and two models are presented: the classical discontinuous one, in which microcracks close instantaneously, and the new continuous one, in which they close gradually. The results for both models are compared and verified in order to achieve the best fitting the experimental data. Detailed quantitative and qualitative analysis of obtained solutions confirms the necessity and correctness of an application of the continuous damage deactivation concept.
Źródło:
Acta Mechanica et Automatica; 2007, 1, 2; 15-18
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Causing non-contractual damages according to Albanian law
Autorzy:
Levanaj, Amantia
Arshiaj, Besmira
Powiązania:
https://bibliotekanauki.pl/articles/1036446.pdf
Data publikacji:
2015
Wydawca:
Academicus. International Scientific Journal publishing house
Tematy:
causing damage
moral damage
fault
causal connection
compensation of damage
Opis:
This study is mainly focused on handling the causing non-contractual damage, achieving a theoretical analysis of its constituent components as fault, causal connection, unlawful act or omission and damage compensation. Non-contractual liability is provided by our civil code, defining it as at fault or without fault liability. Our country, as a country in transition needs legal investment and its implementation into practice. One of the cases on which liability on damage compensation arises is the combination of the rights of persons, whose dignity has been infringed against the right that is explicitly sanctioned in the Constitution of the Republic of Albania, freedom of speech as well as thought, fundamental principles of law, but always without thereby infringing the dignity of a subject of law and and being faced with moral and material damages. In order to handle legally this issue as well as its civil legal consequences that threaten to influence on the entities that breach the law, but also their sensibilization. Hereafter I am handling the theoretical and legal way – the analysis of such a case, under legal - civil perspective.
Źródło:
Academicus International Scientific Journal; 2015, 11; 166-174
2079-3715
2309-1088
Pojawia się w:
Academicus International Scientific Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New Characteristics in the Assessment of Reliability of Machines and Devices
Autorzy:
Kopania, Gabriela
Kuczmaszewska, Anna
Powiązania:
https://bibliotekanauki.pl/articles/2023856.pdf
Data publikacji:
2021-12
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
reliability
damage intensity function
cumulative damage
Opis:
The aim of this work is to present new reliability characteristics expressed as functions of some variable expressing the measure of effective operation of a machine or a device. These characteristics can be used for both renewable and non-renewable objects. Their mathematical idea reflects the essence of already known characteristics, i.e. it expresses the probability of failure but expressed as a function of a variable, not necessarily identified with time.
Źródło:
Management and Production Engineering Review; 2021, 14, 4; 45-52
2080-8208
2082-1344
Pojawia się w:
Management and Production Engineering Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prediction of estimates of technical object’s reliability on the basis of damage determined from lindberg levy’s claim and multiplicity of the set specified from ergodicity stream damage
Autorzy:
Lindstedt, P.
Sudakowski, T.
Grądzki, R.
Powiązania:
https://bibliotekanauki.pl/articles/245098.pdf
Data publikacji:
2013
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
damage identification
damage flux ergodicity
reliability estimators
Opis:
During the exploitation one problem still unsolved is that of determining reliability characteristics for single (individual or small set) technical object. This particularly concerns identification of damage set (parametrical and momentary) as well as determination of substitute cardinality of objects set, where in fact this equals 1, 2, 3 at the most. The article presents a method of determining parametrical and momentary damages from iteration equations: D K= aRb DK + bRbU , (1) UW = aRc U + bRc DK , (2) where: DK – complex diagnostic signal, UW – net environment signal (manner of use), aRb – technical condition parameter, aRc – exploitation condition parameter (exploitation potential), bRb – parameter of environment (manner of use) influence intensity on technical condition, bRc – intensity parameter of technical condition (physical wear) influence on technical object operation quality. Assumption is made that if current value of aRb technical condition parameter is higher than aRb dop (permissible) stemming from central limit theorem, parametrical damage occurs and analogically if value of exploitation condition parameter aRc is higher that aRc dop, momentary damage occurs. Additional assumption is made that substitute cardinality of objects set might be deputized by properly long observation of single object, as resulting from assumption of damage flux ergodicity. Therefore, having damages number (parametrical and momentary) and large enough substitute cardinality for a single object, unreliability estimators might be calculated and thus reliability characteristics of technical object. Presented method of determining reliability characteristics is based on virtually not dangerous parametrical and momentary damages that occur before extremely dangerous catastrophic damage. Method has been verified in practices on bearing systems of two pump complexes of second grade pump station in Jurowce Water Purification Plant of Białystok Water Department.
Źródło:
Journal of KONES; 2013, 20, 1; 179-184
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physical vulnerability to flood inundation: As the mitigation strategies design
Autorzy:
Azmeri, Azmeri
Yunita, Halida
Safrida, Safrida
Satria, Indra
Jemi, Faris Z.
Powiązania:
https://bibliotekanauki.pl/articles/292316.pdf
Data publikacji:
2020
Wydawca:
Instytut Technologiczno-Przyrodniczy
Tematy:
architectural damage
flood
physical vulnerability
structural damage
Opis:
Flood with intense rainfall and inadequate drainage system leads to flood inundation in residential areas, which in turn damages the housing components and causes a loss. The different level of flood inundation at various affected locations caused varying degrees of losses. This study aimed to identify the damage conditions and analysed the physical loss of the residential building components. The physical vulnerability level is influenced by two damage qualification: the structural and architectural damages. The third-order polynomial function approach produces the best model for both qualifications, yielding the smallest average of errors (RMSE) of 0.0187 for the structural quality and 0.0672 for the architectural quality. The amount of losses related to the architectural elements of the house is smaller compared to the structural one as it is not its main component. This approach is useful as a guide in determining the post-flood handling rehabilitation cost of both structural and architectural elements that will be more appropriate for future conditions. This information is essential as effective management to design flood disaster mitigation strategies and may serve as a basis for flood risk management.
Źródło:
Journal of Water and Land Development; 2020, 46; 20-28
1429-7426
2083-4535
Pojawia się w:
Journal of Water and Land Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Scalar and vector time series methods for vibration based damage diagnosis in a scale aircraft skeleton structure
Skalarne i wektorowe szeregi czasowe w diagnostyce uszkodzeń opartej na analizie drgań na przykładzie modelu szkieletu samolotu
Autorzy:
Kopsaftopoulos, F. P.
Fassois, S. D
Powiązania:
https://bibliotekanauki.pl/articles/279265.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
structural health monitoring (SHM)
damage detection
damage identification
Opis:
A comparative assessment of several scalar and vector statistical time series methods for vibration based Structural Health Monitoring (SHM) is presented via their application to a laboratory scale aircraft skeleton structure in which different damage scenarios correspond to the loosening of different bolts. A concise overview of scalar and vector methods, that is methods using scalar or vector signals, statistics, and corresponding models, is presented. The methods are further classified as nonparametric or parametric and response-only or excitation-response. The effectiveness of the methods for both damage detection and identification is assessed via various test cases corresponding to different damage scenarios. The results of the study reveal various facets of the methods and confirm the global damage diagnosis capability and the effectiveness of both scalar and vector statistical time series methods for SHM.
W pracy zawarto analizę porównawczą kilku skalarnych i wektorowych statystycznych szeregów czasowych stosowanych w technikach monitorowania stanu konstrukcji (SHM) na podstawie ich skuteczności w zastosowaniu do wykrywania uszkodzeń szkieletowej struktury laboratoryjnego modelu samolotu dla różnych scenariuszy uszkodzeń wywołanych poluzowaniem połączeń śrubowych. Zaprezentowano krótki przegląd skalarnych i wektorowych metod analizy, tj. bazujących na skalarnych i wektorowych sygnałach i statystykach, oraz odpowiadające im modele. Metody te sklasyfikowano jako nieparametryczne i parametryczne oraz oparte wyłącznie na informacji o odpowiedzi dynamicznej układu lub relacji pomiędzy wymuszeniem i odpowiedzią. Efektywność rozważanych metod oceniono na podstawie kilku eksperymentalnych przypadków badawczych odpowiadających różnym scenariuszom uszkodzeń modelu. Wyniki badań ujawniły różne aspekty zastosowanych technik analizy i potwierdziły przydatność skalarnych i wektorowych szeregów czasowych w diagnostyce i monitorowaniu stanu konstrukcji (SHM).
Źródło:
Journal of Theoretical and Applied Mechanics; 2011, 49, 3; 727-756
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ pory roku na uszkodzenia drzewostanów olchowych podczas trzebieży wczesnej
Influence of the season on damage in black alder stands during early thinning
Autorzy:
Grzywiński, W.
Turowski, R.
Naskrent, B.
Powiązania:
https://bibliotekanauki.pl/articles/978921.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
logging
tree damage
stand damage rates
Alnus glutinosa
Opis:
The paper presents the comparison of the influence of the season (winter and summer) on the level of damage to trees remaining after the timber harvest during early thinning in young alder stands. The study was carried out in black alder stands aged 38 and 40 years located in north−eastern Poland (Płaska Forest District). Chainsaw logging was performed in the cut−to−length harvest system, while timber was extracted using an agricultural tractor with a trailer with manual timber loading and unloading. The number and share of damaged trees and stand damage rates were estimated in a particular season of the year. Logging resulted in the damage of 8.3% to residual trees. Almost twice as many trees were damaged in summer as in winter (p=0.001). Significantly higher share of trees in 3rd, 4th, and 5th damage classes was found. Only the damage of timber fibers (6th class) did not differ significantly between analyzed seasons. The stand weighted damage rate (W) ranged in winter from 0.12 to 0.38, and in summer between 0.12 and 0.80. In turn, the value of weighted coefficient of damaged trees in the remaining stand amounted to 10.24−60.15 in winter, and 19.07−119.64 in summer. Both W (p<0.01) and WDI (p<0.05) indices were twice higher in the summer than in the winter period.
Źródło:
Sylwan; 2020, 164, 05; 365-372
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of rolling bearing life with damage curve approach
Autorzy:
Mehdigholi, H.
Mirzaei Rafsanjani, H.
Behzad, M.
Powiązania:
https://bibliotekanauki.pl/articles/260574.pdf
Data publikacji:
2011
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
rolling bearing
prognostic
damage mechanics
Damage curve approach
Opis:
The ability to determine the bearing life time is one of the main purposes in maintenance of rotating machineries. Because of reliability, cost and productivity, the bearing life time prognostic is important. In this paper, a stiffness-based prognostic model for bearing systems is discussed. According to presumed model of bearing and fundamental of damage mechanics, damage curve approach is used to relate stiffness of vibratory system and bearing running life. Furthermore, using the relation between acceleration amplitude at natural frequency and stiffness, final relation between acceleration amplitude at natural frequency and running life time according to damage curve approach can be established and the final running time is predicted. Experiments have been performed on self alignment bearing under failures on inner race and outer race to calibrate and to validate the proposed model. The comparison between model-calculated data and experimental results indicates that this model can be used effectively to predict the failure lifetime and the remaining life of a bearing system.
Źródło:
Polish Maritime Research; 2011, 3; 66-70
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lokalizacja uszkodzenia z zastosowaniem filtracji modalnej - weryfikacja eksperymentalna
Damage location with use of modal filtering - experimental verification
Autorzy:
Mendrok, K.
Powiązania:
https://bibliotekanauki.pl/articles/328284.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
filtr modalny
wykrywanie uszkodzeń
lokalizacja uszkodzeń
uszkodzenie
modal filter
damage
damage detection
damage localization
Opis:
Filtracja modalna ma wiele zastosowań w analizie dynamiki obiektów. Ostatnio w piśmiennictwie naukowym można znaleźć przykłady zastosowania filtracji modalnej do wykrywania uszkodzeń. Filtr modalny służy do rozkładu odpowiedzi układu na składowe związane z kolejnymi współrzędnymi modalnymi. Gdy więc filtrujemy widmowe funkcje przejścia układu, na wyjściu filtru pojawia się charakterystyka z jednym tylko maksimum, związanym z częstotliwością drgań własnych, na którą filtr był nastrojony. Zmiany strukturalne (np. spadek sztywności lub masy związany z uszkodzeniem) powodują pojawienie się dodatkowych pików na charakterystyce wyjściowej filtru. Filtr modalny jest więc świetnym narzędziem do detekcji uszkodzeń o następujących zaletach: niewielkie wymagania obliczeniowe, łatwość automatyzacji, niewrażliwość na zmiany warunków zewnętrznych. Posiada jednak istotną wadę - nie daje informacji o miejscu wystąpienia uszkodzenia. Artykuł przedstawia rozwiązanie, które likwiduje tę wadę. Pokazana metoda jest najpierw sprawdzana na danych symulacyjnych, a następnie na przebiegach zarejestrowanych podczas eksperymentu laboratoryjnego.
Modal filtering has numerous applications in analysis of objects dynamics. Lately in the literature one can find an example of use of modal filtering for damage detection. Modal filter decomposes the system responses into the modal coordinates, and thus, on the output of the filter, one has the frequency response with only one peak corresponding to the natural frequency to which the filter was tuned. Structural modification (e.g. drop of stiffness or mass due to damage) causes appearance of spurious peaks on the output of the modal filter. Modal filter is, therefore, a great indicator of damage detection with such advantages as low computational effort due to data reduction, easiness of automation and lack of sensitivity to environmental changes. It has however one serious fault - it does not provide any information about damage location. The paper presents a solution, that liquidates this disadvantage. Proposed method is first tested on numerical example and than on the data recorded during laboratory experiments.
Źródło:
Diagnostyka; 2008, 1(45); 85-90
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonlinear Fatigue Damage Accumulation
Autorzy:
Dębski, D. K.
Powiązania:
https://bibliotekanauki.pl/articles/97967.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
cumulative fatigue damage
fatigue damage accumulation
cumulative damage rules
load interaction effects
fatigue life prediction
Opis:
One important element of any computational fatigue analysis is the adoption of a hypothesis of fatigue damage accumulation. The most commonly used is the hypothesis of linear accumulation of fatigue damage called the Palmgren-Miner hypothesis. This linear hypothesis does not take into account a factor of great importance: the mutual influence of consecutive fatigue load sequences on each other. In the presented paper, only two consecutive load sequences linked by mutual relations have been analyzed and the results of the analysis have been shown. A more complex form which takes into account the full load history would create complex formula difficult to use. Perhaps, we should go in this direction, especially that today we have enormous computing power at our disposal.
Źródło:
Fatigue of Aircraft Structures; 2015, 7; 18-23
2081-7738
2300-7591
Pojawia się w:
Fatigue of Aircraft Structures
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The assessment of object usability on the basis of instantaneous values of technical condition and regulation state parameters
Autorzy:
Lindstedt, P.
Sudakowski, T.
Powiązania:
https://bibliotekanauki.pl/articles/246863.pdf
Data publikacji:
2012
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
parametric damage
instant damage
technical condition parameter
reliability characteristics
Opis:
In the process of using a complex technical object, it is deregulated, worn and its reliability is decreased. Therefore, it is required that its status, technical state and reliability should be observed during its normal use and handling. The results of such observations allow a synthetic (complex) assessment of suitability of the object, determining its ability to properly carry out its tasks in accordance with its intended purpose. A continuous observation of changes of technical condition on the basis of relationship between the diagnostic signals (output) and the input signals (environment) allow evaluation of the regulation state of the object [4, 5]. An innovative method of assessment of the operated system usability presented in the article concerns an adequate analysis of the changes to aRb technical condition and aRc, regulation state current parameters formed from coupled equations of state (1 and 2) [1, 2, 3, 7]. While analysing the waveforms of instantaneous values of aRb technical condition and aRc regulation state parameters, it has been observed that parameter and instantaneous damage can be identified on the basis of quantitative relationships between the instantaneous threshold value of dpr and the corresponding instantaneous value of dpr dop, which are calculated from the following formulas (7, 8, 9). It is assumed that damage exists if for the instant theta i . dpri greather than d prdop i . Having the quantity of damage, reliability characteristics can be determined for every time of technical object exploitation (prior to the occurrence of catastrophic damage) [6].
Źródło:
Journal of KONES; 2012, 19, 2; 305-312
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The specific abiotic and biotic damage of poppy (Papaver somniferum) — a review
Autorzy:
Havel, Jiri
Powiązania:
https://bibliotekanauki.pl/articles/2199905.pdf
Data publikacji:
2019-04-01
Wydawca:
Instytut Hodowli i Aklimatyzacji Roślin
Tematy:
abiotic damage
edible poppy
unusual biotic damage
Papaver somniferum
Opis:
The poppy (Papaver somniferum) is a very sensitive crop, suffering from specific types of abiotic and biotic damage. Herbicides, soil conditions, weather and their combination are frequent causes of abiotic damage. Specific type of herbicide deformation is spiral stem. Damage caused by sequence of registered herbicides is also known. Massive solidification of the soil can cause fat growth of root neck or beet deformation of roots. Seedless capsules as a specific poppy damage that is caused by the influence of stress factors (herbicides, soil conditions, high amount of plant chemicals) at elongation growth phase, followed by inappropriate weather at the blossom time. Atypical biotic damage can be caused by diseases Fusarium sp., Sclerotinia sclerotiorum, Botryotinia fuckeliana or bacterial infection. Visual symptoms of fusarial infection (orange colored plant parts or pinkish mycelium) occur only rarely. The often-detected traces of fusariotoxins in the seeds suggest, that the hidden infection of poppy by Fusarium is also possible. Sporadically, Sclerotinia sclerotiorum and Botryotinia fuckeliana can infect stems and capsules too. Lower intensity of bacterial infection (Erwinia carotovora ssp. carotovora) causes the black colored stem basis and root neck. Verticillium sp. causes similar symptoms and so these infections can confused for each other. If the pest damage is unusual, is questionable, because papaver stem midge (Timaspis papaveris) occurs commonly, but this pest is not too well known. The poppy capsule weevil (Neoglocianus maculaalba) is well known in the warmest growth areas and it is now extending to the colder areas too. Hares and roes cause specific biotic damage, when they eat only the buds in the elongation growth stage
Źródło:
Biuletyn Instytutu Hodowli i Aklimatyzacji Roślin; 2018, 284; 75-94
0373-7837
2657-8913
Pojawia się w:
Biuletyn Instytutu Hodowli i Aklimatyzacji Roślin
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Machine Learning (ML) Methods in Assessing the Intensity of Damage Caused by High-Energy Mining Tremors in Traditional Development of LGOM Mining Area
Autorzy:
Witkowski, Michał
Powiązania:
https://bibliotekanauki.pl/articles/2091567.pdf
Data publikacji:
2022
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
mining damage
housing construction
compensation
damage risk
Machine Learning
Opis:
The paper presents a comparative analysis of Machine Learning (ML) research methods allowing to assess the risk of mining damage occurring in traditional masonry buildings located in the mining area of Legnica-Głogów Copper District (LGOM) as a result of intense mining tremors. The database of reports on damage that occurred after the tremors of 20 February 2002, 16 May 2004 and 21 May 2006 formed the basis for the analysis. Based on these data, classification models were created using the Probabilistic Neural Network (PNN) and the Support Vector Machine (SVM) method. The results of previous research studies allowed to include structural and geometric features of buildings,as well as protective measures against mining tremors in the model. The probabilistic notation of the model makes it possible to effectively assess the probability of damage in the analysis of large groups of building structures located in the area of paraseismic impacts. The results of the conducted analyses confirm the thesis that the proposed methodology may allow to estimate, with the appropriate probability, the financial outlays that the mining plant should secure for the repair of the expected damage to the traditional development of the LGOM mining area.
Źródło:
Budownictwo i Architektura; 2022, 21, 1; 5--17
1899-0665
Pojawia się w:
Budownictwo i Architektura
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of two types of moisture treatment of wheat grain on endosperm damage
Autorzy:
Wozniak, W.
Powiązania:
https://bibliotekanauki.pl/articles/25696.pdf
Data publikacji:
1995
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
internal damage
X-ray detection
endosperm damage
grain
mechanical damage
wheat grain
kernel
moisture gradient
Źródło:
International Agrophysics; 1995, 09, 2
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A modified model of residual strength prediction for metal plates with through-thickness cracks
Autorzy:
Li, Yanping
Wang, Jianjun
Guo, Weiguo
Guo, Jin
Powiązania:
https://bibliotekanauki.pl/articles/281643.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
residual strength
damage degree factor
crack
multiple site damage
Opis:
A new model, accurate and easy-to-apply, has been proposed to predict the residual strength for metal plates intact or with different damage degrees. In this model, we introduced the damage degree factor (DDF) to quantify the initial damage condition of a plate. The middle crack tension (M(T)) tests and multiple site damage (MSD) tension tests were performed on plate specimens in aluminum alloy LY12-CZ and 2524-T3, respectively. For various damage degrees, the predicted results of this new model showed an improved correlation with test results compared to the net section yield criterion, K-apparent criterion and Duong’s method.
Źródło:
Journal of Theoretical and Applied Mechanics; 2019, 57, 3; 537-547
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of the Fatigue Load Level and the Hole Diameter on the Laminate Structure’s Fatigue Performance
Autorzy:
Zalewska, M.
Powiązania:
https://bibliotekanauki.pl/articles/97951.pdf
Data publikacji:
2018
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
composite
fatigue
damage
Opis:
Damage tolerance of composite aircraft structure is one of the main areas of research, important when a new product is being developed. There are a number of variables, such as damage characteristics (dent depth, delamination area) and loading parameters (load type, amplitude of cyclic loading, load sequence) that need to be investigated experimentally [1]. These tests of composite materials are usually performed at an element level and are carried out in order to validate the analytical model, developed to predict the full-scale component’s behaviour. The paper presents the results of compression testing of the [36/55/9] carbon fibre/epoxy laminate, manufactured with the Automated Fibre Placement technology (AFP) and subjected to static and fatigue loads. The laminate compression loading mode was achieved through sandwich 4-point flexure. At the stage of fatigue testing, two parameters were investigated: the damage size, simulated by the hole diameter and the fatigue load level. Based on the test results, the laminate fatigue load limit equal to 75% of the OHC failure load was evaluated. By collating the static and fatigue tests results, the damage tolerance characteristic of the considered laminate was created.
Źródło:
Fatigue of Aircraft Structures; 2018, 10; 21-30
2081-7738
2300-7591
Pojawia się w:
Fatigue of Aircraft Structures
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Early detection of bearing damage by means of decision trees
Autorzy:
Kilundu, B.
Dehombreux, P.
Letot, Ch.
Chiementin, X.
Powiązania:
https://bibliotekanauki.pl/articles/384675.pdf
Data publikacji:
2009
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
damage detection
bearing damage
envelope detection
decision trees
preventive maintenance
Opis:
This paper presents a procedure for early detection of rolling bearing damages on the basis of vibration measurements. First, an envelope analysis is performed on bandpass filtered signals. For each frequency range, a feature indicator is defined as sum of spectral lines. These features are passed through a principal component model to generate a single variable, which allows tracking change in the bearing health. Thresholds and rules for early detection are learned thanks to decision trees. Experimental results demonstrate that this procedure enables early detection of bearing defects.
Źródło:
Journal of Automation Mobile Robotics and Intelligent Systems; 2009, 3, 3; 70-74
1897-8649
2080-2145
Pojawia się w:
Journal of Automation Mobile Robotics and Intelligent Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Classification of Damages of Palletized Loads in Road Transport and Its Impact on Environmental Protection
Autorzy:
Tkaczyk, Sławomir
Powiązania:
https://bibliotekanauki.pl/articles/2174898.pdf
Data publikacji:
2022
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
cargo
cargo damage
classification of damage
carbon footprint
environmental protection
Opis:
Cargo damage in extreme situations may threaten the safety of people participating in the further stages of the transport task in the distribution chain. Regardless of this, the damage also affects the unplanned extension of the delivery time or even prevents its further execution. The final and inevitable consequence is unplanned additional costs that will be charged to the shipper preparing the cargo for shipment. Additional costs will be incurred, direct (materials for repackaging and load securing, fuel, tolls, insurance) and indirect costs (carbon footprint of the materials produced and the fuel used by vehicles, increased traffic congestion, and the safety of road users). Their consequence will be an unnecessary increase in the pollution of the natural human environment. The article presents the classification of damage to palletised loads. The correctness of the proposed classification was to be achieved by analysing the results of surveys and broadly understood consultations with business entities dealing with the damage to palletised loads daily. The small number of completed questionnaires indicates the need to develop a new, less detailed questionnaire and a possible simplification of the proposed classification of damage to palletised loads. Based on the numerous discussions and meetings held during the consultations regarding the quantity and quality of cargo damage, it can be concluded that this is a very complex, sensitive topic. Literature review studies can confirm it, including industry studies and published statistical data. It is practically difficult to determine the size of damage to palletised loads in road transport. The proposed classification of damage to palletised loads allows for the definition of dangers, difficulties and, consequently, direct and indirect costs of transport, which can be remedied, and certainly significantly reduced. Minimising damaged and destroyed loads result in both a reduction of the direct costs of damaged products and a secondary reduction in the consumption of natural resources of the environment necessary to re-manufacture damaged or destroyed products. It also contributes to reducing the carbon footprint, an important issue, especially nowadays.
Źródło:
Rocznik Ochrona Środowiska; 2022, 24; 457--471
1506-218X
Pojawia się w:
Rocznik Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling ductile damage of steel in aggressive environment
Autorzy:
Kucharski, R.
Powiązania:
https://bibliotekanauki.pl/articles/1933197.pdf
Data publikacji:
2006
Wydawca:
Politechnika Gdańska
Tematy:
stress corrosion damage
reaction-diffusion equations
damage evolution equation
FEM
Opis:
This paper is a proposition of a new damage model, extended to include the influence of the external environment, based on the Gurson yield function and a new damage evolution equation. The model also contains a mass transport equation based on Pick's law. A comparison of experimental and numerical results is included.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2006, 10, 4; 417-425
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Approach to Damage Detection in the Aircraft Structure with the Use of Integrated Sensors – The Symost Project
Autorzy:
Dragan, K.
Dziendzikowski, M.
Leski, A.
Dworakowski, Z.
Uhl, T.
Powiązania:
https://bibliotekanauki.pl/articles/97801.pdf
Data publikacji:
2012
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
averaged damage index
full scale fatigue test
damage growth monitoring
Opis:
This paper presents an approach to damage growth monitoring and early damage detection in the structure of PZL – 130 ORLIK TC II turbo-prop military trainer aft using the statistical models elaborated by the Polish Air Force Institute of Technology (AFIT) and the network of the sensors attached to the structure. Drawing on the previous experiences of the AFIT and AGH in structural health monitoring, the present research will deploy an array of the PZT sensors in the structure of the PZL -130 Orlik TC II aircraft. The aircraft has just started Full Scale Fatigue Test (FSFT) that will continue up to 2013. The FSFT of the structure is necessary as a consequence of the structure modification and the change of the maintenance system - the transition to Condition Based Maintenance. In this paper, a novel approach to the monitoring of the aircraft hot-spots will be presented. Special attention will be paid to the preliminary results of the statistical models that provide an automated tool to infer about the presence of damage and its size. In particular, the effectiveness of the selected signal characteristics will be assessed using dimensional reduction methods (PCA) and the so-called averaged damage indices will be delivered. Moreover, the results of the signal classification based on the neural network will be presented alongside the numerical model of the wave propagation. The work contains selected information about the project scope and the results achieved at the preliminary stage of the project.
Źródło:
Fatigue of Aircraft Structures; 2012, 4; 10-16
2081-7738
2300-7591
Pojawia się w:
Fatigue of Aircraft Structures
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Etyka zawodowa likwidatora szkód w towarzystwie ubezpieczeniowym
Autorzy:
Zasada, Jarosław
Powiązania:
https://bibliotekanauki.pl/articles/653080.pdf
Data publikacji:
2011
Wydawca:
Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Tematy:
damage adjuster
personal damage
professioalism of a damage adjuster
profession of public trust confidentiality of aggrieved party records
Źródło:
Annales. Etyka w Życiu Gospodarczym; 2011, 14, 2
1899-2226
2353-4869
Pojawia się w:
Annales. Etyka w Życiu Gospodarczym
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Porównanie klasycznych metod szacowania niskocyklowej trwałości zmęczeniowej z podejściem CDM
Comparison of classical methods for estimating low cycle fatigue with cdm approach
Autorzy:
Burak, M.
Skibicki, D.
Powiązania:
https://bibliotekanauki.pl/articles/95408.pdf
Data publikacji:
2014
Wydawca:
Politechnika Bydgoska im. Jana i Jędrzeja Śniadeckich. Wydawnictwo PB
Tematy:
Continuum Damage Mechanics
Morrow
Smith-Watson-Topper
niskocyklowa trwałość zmęczeniowa
uszkodzenie
continuum damage mechanics
low cycle fatigue
damage
Opis:
W pracy skupiono się na porównaniu podejść szacowania trwałości zmęczeniowej metodami tzw. klasycznymi (Morrow, Morrow (σm), SWT) – szeroko wykorzystywanymi w obliczeniach zmęczeniowych – z podejściem kontynualnej mechaniki uszkodzenia (Continuum Damage Mechanics – CDM).
The study focused on a comparison of approaches for estimating the fatigue life of the so-called classical methods (Morrow, Morrow (σm), SWT) widely used in the fatigue calculation with the approach of Continuum Damage Mechanics (CDM).
Źródło:
Postępy w Inżynierii Mechanicznej; 2014, 3(2); 5-12
2300-3383
Pojawia się w:
Postępy w Inżynierii Mechanicznej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wykrywanie uszkodzeń konstrukcji na podstawie analizy zmian parametrów dynamicznych
Structural damage detection based on changes in dynamic parameters
Autorzy:
Ziaja, D.
Miller, B.
Powiązania:
https://bibliotekanauki.pl/articles/371976.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
uszkodzenia konstrukcji
detekcja uszkodzeń
dynamika
SHM
structural damage
damage detection
dynamics
Opis:
W artykule zaprezentowano ideę monitorowania stanu konstrukcji jako działania wspierającego ochronę środowiska. Przedstawiono, na przykładzie badań dwukondygnacyjnej ramy portalowej, wstępną propozycję procedury umożliwiającej detekcję uszkodzeń połączeń w badanej konstrukcji. Prezentowane w opracowaniu wnioski bazują na pomiarach przyspieszeń w wybranych punktach konstrukcji poddanej wzbudzeniu dynamicznemu. Jako narzędzie do analizy zmian parametrów dynamicznych układu wykorzystano jednowarstwowe, jednokierunkowe sztuczne sieci neuronowe.
The article presents the idea of structural health monitoring as a supporting action to protect the environment. The preliminary proposal of a procedure enabling the damage detection of the joints is shown on the example of a two-storey portal frame. Conclusions, presented in the paper, based on the measurement of accelerations in selected points of structure, subjected to dynamic excitation. Single-layer, feed-forward artificial neural networks were used as a tool for the analysis of changes in the dynamic parameters.
Źródło:
Zeszyty Naukowe. Inżynieria Środowiska / Uniwersytet Zielonogórski; 2017, 166 (46); 75-84
1895-7323
Pojawia się w:
Zeszyty Naukowe. Inżynieria Środowiska / Uniwersytet Zielonogórski
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multiscale approach to structure damage modelling
Wieloskalowe podejście do modelowania uszkodzeń konstrukcji
Autorzy:
Paćko, P.
Uhl, T.
Powiązania:
https://bibliotekanauki.pl/articles/280897.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
multiscale damage modelling
delamination modelling
ductile damage modelling and experimental validation
Opis:
The paper deals with the problem of modelling of different types of damages in metallic and composite structures. The modelling of damage and fracture plays an important role in design and implementation of Structural Health Monitoring systems, particularly it is very important in prognosis of the rest of safe life of structures. The authors overview and analyse the existing methods and available tools of damage and fracture modelling. The application of selected models for structure damage and fracture modelling in macro and micro scale simulations is the main subject of this paper. Two groups of models are considered; the first group consists of models capable of predicting brittle fracture, second – models used for ductile damage evaluation. In the latter group, macro and multiscale models are presented. Finally, the multiscale damage model based on a representative volume element is presented. The grain structure modelling and its FE implementation are discussed in conjunction with application of ductile damage criterion for grain structures. Several numerical examples are presented.
Modelowanie uszkodzeń i pęknięć konstrukcji odgrywa bardzo istotną rolę w projektowaniu i implementacji systemów monitorowania stanu konstrukcji (SHM) oraz jest szczególnie istotne dla prognozy czasu bezawaryjnej pracy obiektów. Autorzy prezentują przegląd i analizę dostępnych metod i narzędzi pozwalających na modelowanie uszkodzeń konstrukcji metalicznych i kompozytowych. Głównym tematem pracy jest zastosowanie wybranych modeli uszkodzeń konstrukcji do symulacji uszkodzeń w skalach mikro oraz makro. Przeanalizowane zostały dwie grupy modeli; modele pozwalające na symulację zjawiska pękania kruchego oraz modele wykorzystywane do analizy uszkodzeń plastycznych. W drugiej grupie rozpatrzono modele w skali makro oraz modele wieloskalowe. W pracy zaprezentowano wieloskalowy model bazujący na elemencie objętościowym (RVE). Omówione zostało modelowanie struktur ziarnistych oraz implementacja z wykorzystaniem metody elementów skończonych w połączeniu z zastosowaniem kryteriów pękania plastycznego dla struktur ziarnistych. W pracy zaprezentowane zostały wyniki symulacji numerycznych oraz ich weryfikacja eksperymentalna.
Źródło:
Journal of Theoretical and Applied Mechanics; 2011, 49, 1; 243-264
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-25 z 1316

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