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1

Finite element model updating of steel-concrete composite bridge: A study case of the Ruri bridge in Vietnam

Nguyen Duc Cong, Salamak Marek, Katunin Andrzej, Gerges Michael, Abdel-Maguid Mohamed

Archives of Civil Engineering

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2023

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Vol. 69, nr 3

425--443

EN

The study presents the finite element (FE) model update of the existing simple-spans steel-concrete composite bridge structure using a particle swarm optimisation (PSO) and genetic algorithm (GA) approaches. The Wireless Structural Testing System (STS-WiFi) of Bridge Diagnostic, Inc. from the USA, implemented various types of sensors including: LVDT displacement sensors, intelligent strain transducers, and accelerometers that the static and dynamic historical behaviors of the bridge structure have been recorded in the field testing. One part of all field data sets has been used to calibrate the cross-sectional stiffness properties of steel girders and material of steel beams and concrete deck in the structural members including 16 master and slave variables, and that the PSO and GA optimisation methods in the MATLAB software have been developed with the new innovative tools to interface with the analytical results of the FE model in the ANSYS APDL software automatically. The vibration analysis from the dynamic responses of the structure have been conducted to extract four natural frequencies from experimental data that have been compared with the numerical natural frequencies in the FE model of the bridge through the minimum objective function of percent error to be less than 10%. In order to identify the experimental mode shapes of the structure more accurately and reliably, the discrete-time state-space model using the subspace method (N4SID) and fast Fourier transform (FFT) in MATLAB software have been applied to determine the experimental natural frequencies in which were compared with the computed natural frequencies. The main goal of the innovative approach is to determine the representative FE model of the actual bridge in which it is applied to various truck load configurations according to bridge design codes and standards. The improved methods in this document have been successfully applied to the Vietnamese steel-concrete composite bridge in which the load rating factors (RF) of the AASHTO design standards have been calculated to predict load limits, so the final updated FE model of the existing bridge is well rated with all RF values greater than 1.0. The presented approaches show great performance and the potential to implement them in industrial conditions.

2

Analiza szklenia strukturalnego dla konstrukcji o złożonym kształcie

Maffeis Massimo, Bombonato Marco, Consolaro Alberto, Barbieri Luca

Świat Szkła

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2022

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R. 27, nr 11

36, 38, 40--42, 49

3

A novel method for identification of damage location in frame structures using a modal parameters-based indicator

Nashta Mina Roodgar, Taghipour Reza, Bozorgnasab Mohsen, Mirgolbabaei Hessam

Archives of Civil Engineering

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2022

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Vol. 68, nr 3

633--643

EN

Diverse strategies for identifying and finding the damages in structures have been continuously engaging to originators within the field. Due to the direct connection between the firmness, characteristic frequency, and mode shapes within the structure, the modular parameters may well be utilized for recognizing and finding the damages in structures. In current consider, a modern damage marker named Damage Localization Index (DLI) is applied, utilizing the mode shapes and their derivative. A finite element model of a frame with twenty and thirty components has been utilized, separately. The numerical model is confirmed based on experimental information. The indicator has been explored for the damaged components of a frame with one bay. The results have been compared with those of the well-known index CDF. To demonstrate the capability and exactness of the proposed method, the damages with low seriousness at different areas of the structures are explored. The results are investigated in noisy condition, considering 3% and 5% noise on modal data. The outcomes show the high level of accuracy of the proposed method for identifying the location of the damaged elements in frames.

4

Numerical and experimental investigations on Mannesmann effect of nickel‑based superalloy

Zhang Zhe, Liu Dong, Man Tongchi, Li Nan, Yang Yanhui, Pang Yuhua, Wang Jianguo

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 3

art. no. e133

EN

The preparation of nickel-based superalloy tubes by rotary tube piercing (RTP) process is still difficult due to the Mannesmann effect (central cracking phenomenon) has not been clarified. The combinations of numerical analysis and experiment verifications method were adopted in the study. The critical parameters for central cracking were determined by experiments. It was found that the evolution process of central cracking for nickel-based superalloy includes voids nucleation, growth and aggregation. Based on the obtained critical parameters, the evolutions of stress, strain, strain rate, temperature and damage were discussed by numerical simulation. By comparing the experiment results and simulation results, the Normalized Cockcroft and Latham (NCL) model was determined as the most suitable model. Considering the influences of temperature and strain rate on the damage threshold, the NCL model of Inconel 718 alloy was established by high-temperature tensile test. Based on the above results, it is found that the maximum shear stress promotes the plastic deformation, which provides necessary conditions for the generation of defects, and the maximum principal stress induces the generation of voids and expansion of micro-cracks, which directly leads to the central cracking. The essence of central cracking is ductile fracture under tensile stress.

5

Finite-element analysis of strengthening the subgrade on the basis of boring and mixing technology

Tiutkin Oleksii, Neduzha Larysa, Kalivoda M.

Transport Problems

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2021

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T. 16, z. 2

189--197

EN

One of the effective techniques to strengthen the subgrade is boring and mixing technology, which is based on the immersion of vertical elements – piles into the subgrade. This method of strengthening significantly affects the stress state of the track superstructure. Two options of the placement of strengthening elements are examined in this paper. To determine the influence of position of strengthening elements on the stress state of the track superstructure, appropriate finite-element models were created. The models fully reflect the geometric and deformation characteristics of a real subgrade, which is strengthened by piles. The calculated stress state of the track superstructure is shown and analyzed in this paper. The main contribution of the paper lies in optimization of the geometric parameters of the technology to reduce the stress state of the "track superstructure–subgrade–soil basement" system. The results show that the location of piles near the rails is more effective than the location of piles near the ballast section.

6

Experimental and theoretical research on large-diameter rock-socketed pile embedded depth

Li Yanfeng, Zhao Jihe, Xiong Ying, Wang Qinghe

Archives of Civil Engineering

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2021

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Vol. 67, nr 2

537--550

EN

A theoretical formula for large-diameter rock-socket depth is developed to support pail embedding in a large bridge pile foundation project. There is a horizontal additional stress concentration at the place where the soil around the rock-socketed pile meets the soil layer under the horizontal load. When the rock-socketed tip stress and bending moment of the pile are relatively small, the pile shows favourable embedment effect and the pile foundation can be considered safe. The function curve of soil resistance around the pile under the action of horizontal force was obtained by finite element analysis. The force characteristics reveal the depth of the largediameter rock-socketed pile under the horizontal load. As the rock-socketed pile rotates under the action of horizontal force, the rock mass resistance around the pile changes according to the cosine. The distribution of pileside soil resistance is proportional to the displacement and distributed according to the sine. A comprehensive correction coefficient of pile shaft resistance β is introduced to deduce the theoretical formula of the depth hr of the large-diameter rock-socketed pile embedded in the bedrock. It is verified through both experiments and numerical analysis.

7

A new index for damage identification in beam structures based on modal parameters

Taghipour Reza, Nashta Mina Roodgar, Bozorgnasab Moshen, Mirgolbabaei Hessam

Archive of Mechanical Engineering

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2021

|

LXVIII, nr 4

375--394

EN

The structural damages can lead to structural failure if they are not identified at early stages. Different methods for detecting and locating the damages in structures have been always appealing to designers in the field. Due to direct relation between the stiffness, natural frequency, and mode shapes in the structure, the modal parameters could be used for the purpose of detecting and locating the damages in structures. In the current study, a new damage indicator named “DLI” is proposed, using the mode shapes and their derivatives. A finite element model of a beam is used, and the numerical model is validated against experimental data. The proposed index is investigated for two beams with different support conditions and the results are compared with those of two well-known indices – MSEBI and CDF. To show the capability and accuracy of the proposed index, the damages with low severity at various locations of the structures containing the elements near the supports were investigated. The results under noisy conditions are investigated by considering 3% and 5% noise on modal data. The results show a high level of accuracy of the proposed index for identifying the location of the damaged elements in beams.

8

Konečno-èlementnaâ modelʹ èlektronno-lučevoj pajki tverdosplavnyh režuŝih èlementov k opravke

Goranskij G.G., Pobol A.I

Zeszyty Naukowe Politechniki Częstochowskiej. Budownictwo

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2020

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Z. 26 (176)

44-55

RU

Sozdany obobŝennye konečno-èlementnye (KÈ) modeli èlektronno-lučevoj obrabotki (ÈLO) poverhnostej dlâ materialov s suŝestvenno otličaûŝimisâ teplofizičeskimi svojstvami, pozvolâûŝie proizvoditʹ rasčet i optimizaciû režimov processa. Dlâ izdelij raznoj geometrii, učityvaâ termodinamiku processa i temperaturnye zavisimosti svojstv materialov, upravlââ geometriej èlektronnogo pučka i ciklogrammoj processa, optimizirovany diapazony ènergeti českih parametrov ÈLO. KÈ modelirovanie nagreva poverhnosti pri ÈLO provedeno dlâ detali ploskoj formy stacionarnym istočnikom so skaniruûŝej razvertkoj, a takže pri vozdejstvii v režime linejnogo peremeŝeniâ luča bez skaniruûŝej razvertki. Dlâ optimizacii èlektronno-lučevogo oplavleniâ pri pajke predložena termodinamičeskaâ KÈ modelʹ, učityvaûŝaâ geometričeskie osobennosti rezcovyh vstavok i teplofizičeskie svojstva sostavlâûŝih ih materialov. Pokazano, čto učet temperaturnoj zavisimosti teplofizičeskih svojstv materialov pozvolâet realizovyvatʹ shemy ÈLO s menʹšej prodolžitelʹnostʹû vozdejstviâ pučka bolʹšej moŝnosti.

EN

Generalized finite-element models for the electron-beam treatment of the surface of materials with significantly different thermophysical properties have been created, allowing the calculation and optimization of process conditions. For products of different geometries, taking into account the thermodynamics of the process and the temperature dependences of the properties of materials, controlling the electron beam geometry and the process cycloramas, the ranges of energy parameters of electron beam processing have been optimized. Finite-element modeling of surface heating during electron-beam processing was carried out for a flatshaped part by a stationary source with scanning, as well as when exposed to linear beam movement without scanning. To optimize electron beam reflow during soldering, a thermodynamic finite-element model is proposed that takes into account the geometric features of the cutter inserts and the thermophysical properties of their constituent materials. It is shown that taking into account the temperature dependence of the thermophysical properties of the materials makes it possible to realize electron beam processing schemes with a shorter duration of exposure to a beam of greater power.

9

Verifying of the finite element model of the bridge based on the vibration monitoring at differente stages of construction

Hernandez W., Viviescas A., Riveros-Jerez C. A.

Archives of Civil Engineering

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2020

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Vol. 66, nr 1

25--40

EN

This paper presents the results of a dynamic response evaluation of a segmental bridge during two construction stages: before connecting the final segment of the bridge and after connecting the final segment of the bridge but prior to opening the bridge to traffic. The vibration signals obtained from Ambient Vibration Testing (AVT) campaigns were processed in order to obtain the modal parameters of the bridge during the two construction stages. Modal parameters experimentally obtained for the first stage were compared with those obtained from Finite Element (FE) models considering different construction loads scenarios. Finally, modal parameters experimentally obtained for the second stage were used to update its corresponding FE model considering two scenarios, before and after the installation of the asphalt pavement. The results presented in this paper demonstrated that a rigorous construction control is needed in order to effectively calibrate FE models during the construction process of segmental bridges.

10

Patient-specific finite element analysis of frictional behavior in different esophageal regions during endoscopy

Lin Chengxiong, Ren Pan, Li Wei, Deng Hengyi, Zhou Zhongrong

Acta of Bioengineering and Biomechanics

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2020

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Vol. 22, no. 2

11--24

EN

Endoscopy is a common and effective method to treat digestive system diseases. Not only can it detect the physiological state of the digestive tract, but also can conduct clinical operations. As a result, it’s of great significance to make clear the relationship between the clinical operation and the complications. Methods: Considering the difficulty in measuring the contact force and determining the stress distribution in real time during endoscopy, a specific-patient finite element model for the frictional behavior at the endoscope-esophagus interface was built in current study. By collecting the CT data of the patient, a 3D esophagus model was built and divided into three characteristic regions (narrow region, thoracic region and abdominal region) according to the physiological structure. Results: Results showed that the radius of the narrowest position was the dominant factor for the maximum von Mises stress when the endoscope passed through the narrow region. For abdominal region and thoracic region, with the increasing coefficient of friction (COF) and amplitude, the total force duo to frictional force (CFSM), frictional dissipation (FD), strain energy (SE) and maximum von Mises stress (Max) all increased correspondingly. Meanwhile, the region of stress concentration gradually approached the initial contact stage. Conclusions: The results can provide theoretical basis and technical support for clinical application and offer some suggestions for medical workers during endoscopy as well.

11

Modyfikacja strukturalna konstrukcji płyty spodniej generatora 113 MW

Bednarz J.

Autobusy : technika, eksploatacja, systemy transportowe

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2017

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R. 18, nr 12

709--715, CD

PL

W pracy przedstawione są wyniki przeprowadzonych badań, których celem była identyfikacja częstotliwości i postaci drgań własnych płyty spodniej generatora przy wykorzystaniu wymuszenia eksploatacyjnego w postaci nominalnej pracy turbozespołu. Praca swoim zakresem obejmuje:1. symulacje komputerowe w oparciu o wcześniej przeprowadzone pomiary drgań; 2. opracowanie koncepcji modyfikacji strukturalnej w oparciu o obliczenia z wykorzystaniem modelu elementów skończonych generatora.

EN

The paper presents the results of conducted research aimed at identifying the frequency and the form of vibration of the generator bottom plate using as the excitation the nominal turbine operation. The work includes: 1. computer simulations based on previously performed vibration measurements; 2. Development of a concept of structural modification of generator bottom plate based on calculations using finite element model.

12

Numerical survey, analysis and assessment of past interventions on historical timber structures : the roof of Valentino Castle

Bertolini-Cestari C., Invernizzi S., Marzi T., Spano A.

Wiadomości Konserwatorskie

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2016

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Nr 45

87--97

EN

The paper analyzes a series of reinforcement interventions performed on the historical timber roof structure of the Valentino Castle in Torino (Italy) some thirty years ago. It is not very common to be able to assess the durability of interventions without relying to accelerated ageing test. In this case a real structure is considered, which was consolidated by one of the authors (C. Bertolini) in the past. Recently the laser scanning survey has strengthened a relevant interest in sectors as monitoring and static assessment of building structures. The high detailed models which is possible to reach, and the chance to foresee the accuracy and the resolution of surface models, make them particularly adaptable for studies concerning conservation and maintenance of cultural heritage. The laser survey models is compared with the documentation of the intervention fulfilled three decades ago, in order to evidence the general safety level of whole complex. The fully three-dimensional geometrical information is input in the finite element code, and a structural model is presented which is able to account for the positive contribution of the roof planking connected above the main truss frame. Both the original planking and the reinforcing planking, put in place some thirty years ago, have been accounted for, considering different degrees of the connection stiffness. The paper, starting from the original design, presents an assessment of the durability of the adopted techniques according to the present situation. The effectiveness of the past interventions is proved by nowadays survey, NDT investigations and numerical simulations.

PL

Artykuł analizuje serię wcześniejszych interwencji wzmacniających na zabytkowej konstrukcji drewnianej dachu w zamku Valentino w Turynie (Włochy) przeprowadzonych około 30 lat temu. Rzadko trafia się możliwość oceny trwałości zastosowanej interwencji bez konieczności polegania na teście przyspieszonego starzenia. W tym przypadku badano prawdziwą konstrukcję, której wzmocnienia dokonała w przeszłości jedna z autorek (C. Bertolini). Rozwój metod badawczych wykorzystujących skaner laserowy wpłynął ostatnio na wzrost zainteresowania takimi obszarami, jak monitorowanie i ocena statyczna konstrukcji budynku. Możliwość uzyskania bardzo szczegółowych modeli oraz możliwość prognozowania dokładności i rozdzielczości modeli powierzchniowych sprawiają, że metoda ta może z powodzeniem być wykorzystywana w badaniach dotyczących konserwacji i zachowania obiektów zabytkowych. Model obiektu uzyskany w wyniku skanu laserowego został porównany z dokumentacją interwencji przeprowadzonej trzydzieści lat wcześniej, w celu sprawdzenia ogólnego bezpieczeństwa całego obiektu. Trójwymiarowe dane geometryczne zostały wprowadzone do kodu elementów skończonych w celu wygenerowania modelu konstrukcji. Model ten uwzględniał pozytywne oddziaływanie deskowania dachu połączonego z konstrukcją wiązarów. Zarówno oryginalne deskowanie, jak też deskowanie wzmacniające, zastosowane ok. 30 lat temu, zostały uwzględnione w analizie, z odniesieniem do różnego stopnia sztywności połączeń. Artykuł, wychodząc od oryginalnego projektu, prezentuje ocenę trwałości zastosowanych rozwiązań w świetle sytuacji dzisiejszej. Skuteczność podjętych w przeszłości interwencji została potwierdzona przez badania przeprowadzone obecnie, analizy metodami nieniszczącymi oraz symulacje numeryczne.

13

An influence of auditory chain components’ stiffness on vibrations characteristics measured by a finite-element model of the middle ear structure

Samborski S., Rusinek R., Szymański M.

Vibrations in Physical Systems

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2012

|

Vol. 25

347--353

EN

The problem of modelling of middle ear auditory chain functioning is still very difficult to be made precisely in comparison with the real ossicles’ behaviour observed experimentally. The main reason for this is geometrical complexity and a number of material characteristics of the ossicles themselves. Here, FEM is engaged to model human middle ear work because this method allows for reconfiguring of complex auditory chain geometry, various material models etc. and provides good accuracy.

14

Finite element model updating of reinforced concrete beams with honeycomb damage

Ismail Z.

Archives of Civil Engineering

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2012

|

Vol. 58, nr 2

135-151

EN

A method of detecting honeycombing damage in a reinforced concrete beam using the finite element model updating technique was proposed. A control beam and two finite element models representing different severity of damage were constructed using available software and the defect parameters were updated. Analyses were performed on the finite element models to approximate the modal parameters. A datum and a control finite element model to match the datum test beams with honeycombs were prepared. Results from the finite element model were corrected by updating the Young’s modulus and the damage parameters. There was a loss of stiffness of 3% for one case, and a loss of 7% for another. The more severe the damage, the higher the loss of stiffness. There was no significant loss of stiffness by doubling the volume of the honeycombs.

15

Numerical investigation of AAC wall panels based on the damage plasticity constitutive law

Taddei F., Reindl L., Park J., Butenweg C., Karadogan F.

Cement Wapno Beton

|

2011

|

nr spec.

86-91

EN

This paper gives a short overview on the Ytong Building System and discusses possible seismic verification concepts. Moreover it proposes three-dimensional finite element models for unreinforced and reinforced walls panels in aerated autoclaved concrete on the basis of the concrete damage plasticity constitutive law implemented into the FEM toolkit ABAQUS. The paper focuses on an unreinforced ten panel shear wall and on a reinforced four panel shear wall. For the latter, two different solutions are developed: in the first the reinforcement is directly embedded into the AAC mesh, while in the second grouted cores around the reinforcement bars are taken into account. The quasi-static loading condition was simulated using both static and dynamic implicit analysis, switching from the former to the latter at the occurrence of nonlinearities. The simulation results show that the AAC shear wall models can correctly represent the load-displacement responses as well as the cracking patterns and crack propagations. The concrete damage plasticity constitutive law allows for a proper representation of the cyclic behavior and the damage accumulation of AAC shear walls, which is very important for the performance-based design of structures under seismic loading. Further researches are recommended in order to improve the results and to investigate different combinations of applied axial load, aspect ratios and reinforcement details. The long term goal is the development of a feasible and powerful deformation based seismic verification procedure for the Ytong Building System.

16

Vulnerability analysis of aircraft fuselage subjected to internal explosion

Dacko A., Toczyski J.

Archive of Mechanical Engineering

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2011

|

Vol. LVIII, nr 4

393-406

EN

The most important task in tests of resistance of aircraft structures to the terorist threats is to determine the vulnerability of thin-walled structures to the blast wave load. For obvious reasons, full-scale experimental investigations are carried out exceptionally. In such cases, numerical simulations are very important. They make it possible to tune model parameters, yielding proper correlation with experimental data. Basing on preliminary numerical analyses - experiment can be planned properly. The paper presents some results of dynamic simulations of finite element (FE) models of a medium-size aircraft fuselage. Modeling of C4 detonation is also discussed. Characteristics of the materials used in FE calculations were obtained experimentally. The paper describes also the investigation of sensitivity of results of an explicit dynamic study to FE model parameters in a typical fluid-structure interaction (FSI) problem (detonation of a C4 explosive charge). Three cases of extent of the Eulerian mesh (the domain which contains air and a charge) were examined. Studies have shown very strong sensitivity of the results to chosen numerical models of materials, formulations of elements, assumed parameters etc. Studies confirm very strong necessity of the correlation of analysis results with experimental data. Without such a correlation, it is difficult to talk about the validation of results obtained from "explicit" codes.

PL

W pracy przedstawiono wybrane aspekty modelowania i symulacji numerycznych odporności struktury cienkościennego kadłuba lotniczego na obciążenia wywołane falą uderzeniową, generowaną przez wewnętrzną detonację ładunku wybuchowego o masie m0. Charakterystyki mechaniczne materiałów przyjęto z pomiarów eksperymentalnych. Zastosowano technikę sprzężenia oddziaływań między strukturą a płynem, Arbitrary Lagrangian-Eulerian, z opcją erozji zniszczonych elementów. Przeanalizowano mechanizmy zniszczenia struktury w zależności od lokalizacji ładunku wybuchowego. Rozpatrzono wpływ różnych parametrów modelu obliczeniowego na wyniki analiz. Zbadano również wpływ wymiarów przestrzeni eulerowskiej na wyniki. Wykazano bardzo silną wrażliwość analizy na przyjęte parametry, wybrane sformułowania elementów (opcje), modele materiałów. Wskazuje to na konieczność korelacji symulacji numerycznych z wynikami eksperymentalnymi. Bez możliwości takich porównań trudno mówić o walidacji modelu obliczeniowego.

17

Simplified and advanced models of a valve system used in shock absorbers

Czop P., Sławik D., Śliwa P., Wszołek G.

Journal of Achievements in Materials and Manufacturing Engineering

|

2009

|

Vol. 33, nr 2

173-180

EN

Purpose: The aim of this paper is to develop a model of a valve system applicable for strain and stress prediction. Design/methodology/approach: The analytical and numerical approaches are presented to provide an overview for available methods and prediction accuracy. Findings: An equivalent numerical model of a disc valve system of different complexity was developed and discussed. Research limitations/implications: It is important to provide a model functionality allowing for calculation of disc stacks supported by a coil spring and stack settings having the opening limiter. Disc stack stress and opening characteristics vs. applied pressure may be determined with simplified analytically derived model and full 2D model including almost all significant forces and moments in a stack of circular plates. An advantage of a simplified disc stack model is possibility of its implementation in an environment supporting matrix operations, e.g. Matlab. Practical implications: A valve system has to withstand the cyclic pressure load across the piston. The number of discs, their diameters and thicknesses directly affect durability of a valve system. Damper force and valve durability expressed in life-cycles are the optimization criteria considering during selection and tuning of a valve system. Originality/value: A new valve system was developed in two versions, i.e. simplified and advanced. The model allows durability prediction at the design stage reducing the testing costs of low-performance valve systems.

18

Experimental and numerical study of damage initiation mechanism in elastomeric composites

Silva Botelho T. D., Bayraktar E.

Journal of Achievements in Materials and Manufacturing Engineering

|

2009

|

Vol. 36, nr 1

65-70

EN

Purpose: Experimental and Finite Element Analysis (FEA) of the damage initiation mechanisms in elastomeric composites were carried out under static loading at room temperature. Double Cantilever Beam (DCB) specimens from natural rubber (NR) vulcanised and reinforced with other materials such as carbon black, silica, fibres and textiles or metals (rubber composites). Design/methodology/approach: Very huge experimental results were compared with that of the Finite Element Analysis (FEA). Damage mechanism has been described with a threshold criterion to identify damage. The damage was evaluated just at the beginning of the tearing by assuming large strain. A typical type of specimen geometry of Double Cantilever Beam (DCB) specimens was considered under static tensile tests conducted on the notched specimens with variable depths. Findings: In this stage of this research, a finite element analysis (FEA) has been applied under the same conditions of this part in order to obtain the agreement between experimental and FEA results. The numerical modelling is a representation of a previous experimental study. The specimen is stretched more than once its initial size, so that large strains occur. A hyper elastic Moonley-Rivlin law and a Griffith criterion are chosen. The finite elements analysis was performed with ABAQUS code (V.6.4.4). Practical implications: A damage criterion was suggested in the case of simple tension conditions by assuming large strain levels. an effective finite elements model has been developed to evaluate notch size effects on the load-displacement elastic response of 3D-DCB type specimen. Originality/value: This study proposes a threshold criterion for the damage just at the beginning of the tearing for Double Cantilever Beam (DCB) specimens from rubber composites and gives a detail discussion for explaining the damage mechanisms. Comparison of FEA results with those of experimental studies gives many facilities for the sake of simplicity in industrial applications.

19

Chemo-mechanical finite element model of deterioration of plain concrete structures

Romanowski P., Cichoń C.

Archives of Civil Engineering

|

2005

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Vol. 51, nr 1

85-106

EN

The degradation of mechanically loaded plain concrete structures under two deterioration mechanism: chlorides diffusion and calcium dissolution, with the influence of the moisture transport in concrete, are considered. It is assumed that the concrete behavior is initially isotropic and described by two scalar damage variables, independently for compression and tension loading conditions. The chemical degradation of concrete is described by means of an additional internal variable, named environmental damage. This damage variable consists with two internal variables which are the measure of deterioration of concrete caused by chloride and calcium ions actions. The usefulness of the proposed method of FE numerical analysis is verified by two examples.

PL

W pracy rozważana jest degradacja konsrtukcji betonowej, pod stałym obciążeniem mechanicznym, poddana dwu mechanizmom zniszczenia: dyfuzji chlorków i wymywania jonów wapnia, z uwzględnieniem transportu wilgoci w betonie. Założone zostało izotopowe początkowo zachowanie betonu i opisane dwoma parametrami zniszczenia, niezależnie dla ściskania i rozciągania. Chemiczna degradacja betonu opisana została przy użyciu dodatkowej zmiennej, nazywanej "parametrem zniszczenia środowiskowego". Na wartość tej zmiennej składają się dwie zmienne będące miarami zniszczenia betonu spowodowanego działaniem chlorków i jonów wapnia. Użyteczność proponowanej skończenie elementowej analizy została zweryfikowana na dwu przykładach.