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1

The Effect of Soil-Structure Interaction (SSI) on Structural Stability and Sustainability of RC Structures

Krishnan Ragi, Sivakumar Vidhya Lakshmi

Civil and Environmental Engineering Reports

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2024

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Vol. 34, no. 1

116--136

EN

The issue of SSI involves how the ground or soil reacts to a building built on top of it. Both the character of the structure and the nature of the soil have an impact on the stresses that exist between them, which in turn affects how the structure and soil beneath it move. The issue is crucial, particularly in earthquake regions. The interaction between soil and structure is an extremely intriguing factor in increasing or reducing structural damage or movement. Structures sitting on deformable soil as opposed to strong soil will experience an increase in static settlement and a decrease in seismic harm. The engineer must take into account that the soil liquefaction problem occurs for soft ground in seismic areas. A reinforced concrete wall-frame dual framework's dynamic reaction to SSI has not been sufficiently studied and is infrequently taken into consideration in engineering practice. The structures’ seismic performance when SSI effects are taken into account is still unknown, and there are still some misconceptions about the SSI idea, especially regarding RC wall-frame dual systems. The simulation study of the soil beneath the foundations significantly impacts the framework's frequency response and dynamic properties. Therefore, the overall significance of SSI in the structural aspect and sustainability aspects will be reviewed in this research.

2

Seismic performance evaluation of a base-isolated steel liquid storage tank with limiting-devices considering soil-structure interaction

Jing Wei, Tian Shuang

Archives of Civil Engineering

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2023

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Vol. 69, nr 4

635--661

EN

Liquid storage tank is widely used in the petrochemical industry, earthquake will lead to structural damage and secondary disasters, and damping control opens up a new way for seismic design of liquid storage tank. Considering soil-structure-fluid interaction, liquid sloshing dynamic behavior and material nonlinearity, a three-dimensional calculation model of shock absorption liquid storage tank is established by combining sliding isolation and displacement-limiting devices. The dynamic responses of the liquid storage tanks under the action of Kobe and El-Centro waves are investigated, and the influence of soil-structure interaction (SSI) on the dynamic response is discussed. The results show that the damping ratio is basically between 30% and 90%. After the SSI is considered, the damping ratio of liquid sloshing wave height is increased, while the damping ratio of the dynamic response of the liquid storage tank is decreased, and the change of elastic modulus has little effect on the damping effect. The sliding isolation with displacement-limiting devices has significant damping control effects on the liquid sloshing wave height and the dynamic responses of the liquid storage tank.

3

Analytical study on dynamic response of cantilever flexible retaining wall

Yang Xiuzhu, Liu Xinyuan, Zhao Shuang, Yu Jun

Archives of Civil Engineering

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2023

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Vol. 69, nr 2

435--453

EN

Based on wave mechanics theory, the dynamic response characteristics of cantilever flexible wall in two-dimensional site are analyzed. The partial derivative of the vibration equation of soil layer is obtained, and the general solution of the volume strain is obtained by the separation of variables method. The obtained solution is substituted back to the soil layer vibration equation to obtain the displacement vibration general solution. Combined with the soil-wall boundary condition and the orthogonality of the trigonometric function, the definite solution of the vibration equation is obtained. The correctness of the solution is verified by comparing the obtained solution with the existing simplified solution and the solution of rigid retaining wall, and the applicable conditions of each simplified solution are pointed out. Through parameter analysis, it is shown that when the excitation frequency is low, the earth pressure on the wall is greatly affected by the soil near the wall. When the excitation frequency is high, the influence of the far-field soil on the earth pressure of the wall gradually increases. The relative stiffness of the wall, the excitation frequency and the soil layer damping factor have a significant effect on the dynamic response of the flexible retaining wall.

4

DeepCwind semi-submersible floating offshore wind turbine platform with a nonlinear multi-segment catenary mooring line and intermediate buoy

Motallebi Mohammad, Ghassemi Hassan, Shokouhian Mehdi

Zeszyty Naukowe Akademii Morskiej w Szczecinie

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2022

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nr 69 (141)

20--34

EN

In this paper, to improve the mechanical behavior of DeepCwind semi-submersible floating offshore wind turbine (FOWT) platform mooring lines, the nonlinear catenary cables of the platform were divided into multi-segment and intermediate buoys. Mathematical formulations of the boundary element method (BEM) governing the dynamics of mooring line systems with buoy devices were described. This study was applied to the OC4-DeepCwind semi-submersible FOWT platform, which is designed for a 200-meter water depth with mooring lines consisting of three catenary steel chain cables at 120° angles to each other. The dynamic response of the multi-segment catenary mooring lines with different buoy radiuses and different positions along the cables was investigated. The full-scale platform was modeled in ANSYS-AQWA software, and the simulations were performed under harsh offshore conditions. The mooring line’s general arrangement, tension, strain and uplift force for different buoy radiuses and their position along the cable are presented and discussed. Moreover, platform motions in three directions (surge, heave, and pitch) were also analyzed. It was concluded that by correctly selecting the buoy volume and position along the cable, the tension of the cable may be reduced by up to 45%. By incorrectly selecting the buoy, the results caused adverse effects.

5

Using the instantaneous angular speed measurement to characterize the transient dynamic response of an inertial system

Valencia Andrés Felipe Rodríguez, Piedrahita Carlos Alberto Romero

Diagnostyka

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2022

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Vol. 23, No. 2

art. no. 2022204

EN

The measurement of instantaneous angular speed in flywheels has been used in Internal Combustion Engines for the diagnosis of faults in the fuel injection systems, combustion quality at idle, ignition system, and especially in the performance assessment of starter motor and battery accumulator, among others. It is the aim of this paper to forecast the use of an experimental flywheel-based test bench, driven by a single-cylinder Internal Combustion Engine and a starter motor, developed to perform research studies in the laboratory of internal combustion engines. It is illustrated the measurement and processing of the instantaneous angular speed of a flywheel to characterize the dynamic response of the inertial system during the run-up and run-out regimes. The mathematical model of the transfer function is presented, relating the angular velocity with the torque transmitted by the starter motor as a first-order system. For the acquisition of the signal, a NI 6009 card is used, while a Matlab computer program is employed to plot the instantaneous angular velocity curves, and also to identify the time response of the system. The time constant is 1.54 seconds, which corresponds to 63.2% of the value of steady state signal in run-up regime.

6

A value of damping factor in relation to the dynamic response for a plate structure

Borkowski Łukasz

Mechanics and Mechanical Engineering

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2021

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Vol. 25, nr 1

47--52

EN

The subject of the research is the analysis of the impact of damping value on the dynamic response of plate. The work presents the areas of dynamic stability and instability for the different damping values and compared with the plate without damping. Furthermore, the nature of solution for each analyzed case was presented. Research by using the dynamic tools such as phase portraits, Poincaré maps, FFT analysis, the largest Lyapunov exponents were performed. The compatibility of the selected method of stability analysis with the Volmir criterion was also presented.

7

Numerical study on the dynamic response of a concrete filled steel tubular long column under axial impact by a rigid-body

Qi Han, Chen Shuohui, Zou Jianlei, Zhang Huidi, Liu Mengsha, Ju Jinsan, Sang Xiuxing

Journal of Theoretical and Applied Mechanics

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2021

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Vol. 59 nr 4

551--563

EN

In this study, refined finite element models of concrete filled steel tubular long columns with length diameter ratio (L/D) of 50 were established, and their dynamic responses under a rigid-body impact were explored. It is found that the form of impact load is only related to and can be predicted from the impact velocity of the rigid-body. The change of axial stress and strain with time is synchronous with that of the impact load. Furthermore, the variation characteristics of axial stress and strain with time are mainly related to the initial velocity of the rigid-body.

8

A Study on Dynamic Behavior of Natural Draft Cooling Tower Considering the Effect of Soil-Structure Interaction

Chitrahalli Lingaraju Mahesh Kumar, Kotagi Girisha Shwetha, Bhaktanakatte Channabasappa Shanthappa, Karigowda Manjunatha

Civil and Environmental Engineering Reports

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2021

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Vol. 31, no. 4

17--32

EN

In this present era, the technology in advanced construction has developed to a very large extent. Some parts of the constructions are still in the improving stage which includes cooling tower construction. Hyperbolic cooling towers are large, thin shell reinforced concrete structures which contribute to power generation efficiency, reliability, and to environmental protection. Cooling towers use evaporation of water to eject heat from processes such as cooling the circulating water used in oil refineries and in power plants. Nowadays in many thermal power plants, we can see the cooling tower. So, preserving this industrial structure is an effort to save the cooling tower from dangerous earthquakes. The present-day cooling towers are exceptional structures in view of their sheer size and complexities. Present paper deals with the study of dynamic response that is modal analysis, seismic analysis of the two different cooling towers varying the H/t ratio and thicknesses with fixity at the base boundary condition, and the soil is modelled as raft for the effect of soil-structure interaction using the direct approach. In this paper, hyperbolic cooling towers are modelled using ANSYS software, which is a finite element software. Results show that the soil-structure interaction effect significantly modifies the earthquake behavior of hyperbolic cooling towers.

9

Dynamic response of the Stuttgart TV Tower measured by classical instruments and GPS technology

Breuer Peter, Chmielewski Tadeusz, Górski Piotr

Archives of Civil Engineering

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2021

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Vol. 67, nr 1

7--38

EN

This paper compares the measurement results of dynamic characteristics, including natural frequencies, damping ratio, and wind-induced responses of the Stuttgart TV Tower (TV Tower), obtained by Lenk in 1959 using classical instruments with those obtained by the authors a few decades later using Global Positioning System (GPS). The objective of this paper was to monitor the response of the TV Tower under wind loading, which is an important tool for the validation of its design, construction, and structural health. During the authors’ GPS measurements, weak and moderate wind speeds occurred most of the time. Only in 2007, the stronger wind observed (90 < V < 100 km/h) at the head of the TV Tower (H=157 m), which caused displacements in the decimetre range. Further measurements in 2011 were carried out, using additional GPS receivers with a higher data rate. The results achieved by the GPS prove that the cross-wind response was larger than the along-wind component for all ranges of wind speed, which occurred during the measurement periods, i.e. from 2002 to 2015. The authors of this paper extended Lenk’s results, by the static and along-wind components, confirmed the first natural frequency, and damping ratio, evaluated by the Random Decrement technique. Mounting a GPS receiver, on the steel antenna mast tip, enabled detection of the second natural frequency fs2 = 0.800 Hz, which is the frequency of the mode shape of the TV Tower steel antenna mast. Lenk did not measure this frequency.

PL

Wieża telewizyjna w Stuttgarcie została oddana do użytkowania w dniu 5 lutego 1956 roku. Konstrukcja wieży składa się z dwóch części: (a) trzonu żelbetowego z głowicą o wysokości 161 m i (b) stalowego masztu antenowego o wysokości 56 m. Całkowita wysokość wieży to 217 m. Średnica zewnętrzna trzonu żelbetonowego wynosi 10,8 m u podstawy trzonu i 5,04 m w górnej części trzonu (poniżej głowicy trzonu). Grubość ściany trzonu zmienia się od 60 cm do 19 cm. W latach 1953-1954 Leonhard zaproponował koncepcję i projekt wieży telewizyjnej. Biuro projektowe Pieckert zaprojektowało system konstrukcyjny. Koncepcję wieży telewizyjnej, jej układ konstrukcyjny, wszystkie założenia do obliczeń statycznych, oszacowanie nakładów finansowych i pierwsze pomiary osiadań fundamentów podane zostały w jednej z prac Leonhardta. W tej pracy zasugerowano także potrzebę pomiaru odpowiedzi wieży telewizyjnej na działanie wiatru. Jako pierwszy dokonał tego Lenk w 1959 roku. W latach 1977 i 1995 stwierdzono pionowe pęknięcia w żelbetowym trzonie wieży, które następnie zostały naprawione. Przyczyny tych pęknięć wyjaśniono jako konsekwencje promieniowania słonecznego i dobowych zmian temperatury powietrza działających na trzon wieży telewizyjnej, wywołujących deformacje płaszcza trzonu. Naprężenia termiczne spowodowały zmienną w czasie „owalizację” trzonu wieży, która z biegiem lat doprowadziła do zmęczenia materiału, czego skutkiem były wyraźnie widoczne podłużne pęknięcia po przeciwnych stronach trzonu wieży telewizyjnej. Autorom niniejszego artykułu nie są znane wcześniejsze pomiary charakterystyk dynamicznych wieży telewizyjnej związane z naprawą powstałych pęknięć. W związku z tym, w 1999 roku autorzy przeprowadzili pierwszą serię pomiarów przemieszczeń wierzchołka wieży telewizyjnej z zastosowaniem techniki satelitarnej GPS. Metodologia pomiarów była podobna do metodologii stosowanej przez innych badaczy. Na tej podstawie autorzy potwierdzili możliwość zastosowania systemu GPS do monitorowania przemieszczeń statycznych, quasi-statycznych i dynamicznych oraz do określania podstawowych charakterystyk dynamicznych (częstotliwości drgań własnych i współczynników tłumienia drgań) istniejących dużych konstrukcji w skali naturalnej. Autorzy cyklicznie monitorowali przedmiotową wieżę telewizyjną do roku 2015. Jednak pomimo podjętego wysiłku w celu zebrania dodatkowych danych pomiarowych, niestety w 2013 i 2015 r. nie było możliwości pomiaru przemieszczeń wieży telewizyjnej pod wpływem silnego wiatru. Niemniej jednak autorzy dokonali analizy danych pomiarowych zgromadzonych w latach 2002, 2005, 2006, 2007, 2008 i 2011, które obejmowały pomiary w zakresie prędkości wiatru od małej do dużej. W dniach 18-19 stycznia 2007 r. w pobliżu wieży zarejestrowano porywy wiatru o prędkości 26 m/s, co spowodowało jej przemieszczenia w zakresie decymetrów.

10

Dynamic response analysis of drill pipe considering horizontal movement of platform during installation of subsea production tree

Wang Fei, Chen Neng

Polish Maritime Research

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2020

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nr 3

22--30

EN

In order to study the dynamic response of a drill pipe under the motion of the float platform, current and waves during the installation of a subsea production tree (SPT), a numerical model was established to analyse the mechanical properties of the drill pipe. The effects of the float platform motion on the mechanical behaviours of the drill pipe are carried out as well as the operation depth, submerged weight of the SPT, current velocity and drill pipe specification. At the same time, the evolution mechanism of the dynamic response of the drill pipe was also explored. The results show that the bending stress of the drill pipe approaches the maximum value when the platform moves to about one fourth of its period. Based on the research, the deeper the operation depth, the smaller the range of motion of the bottom of the drill pipe; the current velocity and the size of drill pipe have the greatest influence on the lateral displacement and bending stress.

11

Analysis of the dynamic response of offshore floating wind power platforms in waves

Li Junlai, Xie Yonghe, Wu Weiguo, Zhang Chi

Polish Maritime Research

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2020

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nr 4

17--25

EN

Floating wind power platforms are in constant motion due to waves when deployed at sea. This motion directly affects the stability and safety of the platform. Therefore, it is very important to study the laws governing the platform’s dynamic response. In this paper, the dynamic characteristics of an offshore floating wind power platform were analysed under nine different sets of operating conditions using a numerical calculation method. Following this, a scaled 1:50 platform model was tested in a tank. Model tests were carried out with different wave conditions, and dynamic response data for the platform were measured and analysed. The hydrodynamic variation rules of floating wind power generation platform in waves were obtained. Some effective measures for maintain the stability and safety of wind power platforms are put forward that can provide a reference for dynamic stability research and the design of floating wind power platforms in the future.

12

Numerical study for evaluation of a vibration based damage index for effective damage detection

Mehboob S., Zaman Khan Q. U., Ahmad S.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2020

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Vol. 68, nr 6

1443--1456

EN

An improved damage detection index for a structural component is proposed, using eigenvalues estimated by means of frequency domain decomposition (FDD) and mode contribution subjected to ambient excitation. It is based on vibration measurements obtained from the acceleration data of a simple steel beam. Since the extraction of modal parameters involves practical limitations and, in general, it is difficult to obtain accurate results, therefore in the proposed method a derivative value of the time series acceleration response, termed modal contributing parameter (MCP), is used in combination with eigenfrequencies. The damage is indicated by element stiffness reduction (ESR). Different damage cases for various stiffness reduction values of 1% to 15% were investigated. Damage identification indices for every single damage and multiple damage cases were calculated. The modified MCP damage detection index showed a high index value, even for low-level damage with an element stiffness reduction of as low as 1% over the existing frequency drop and indices based on mode shape change. MCP index derived from the modal response, considering modal contributions to the entire structural response and eigenvalues for damage detection, improved overall sensitivity and reliability of index results. Both single and multiple cases of damage provided equally accurate results based on the MCP index value.

13

Dynamic response analysis of a thin-walled rectangular plate subjected to thermoacoustic loadings

Dang Zhigao, Mao Zhaoyong

Archives of Thermodynamics

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2020

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Vol. 41, no 1

151--174

EN

For thin-walled structures invariably exposed to thermal and noise environment, their dynamic response is an extreme concern in the design of the component of advanced hypersonic aircraft. To address the problem, three theoretical models are established with three typical graded thermal distributions considered. By introducing the thermal moment, membrane forces and acoustic loadings into the vibration equation of plate, the governing equation is derived and it is solved combined with boundary conditions of the plate, the modal function and velocity compatibility equations at the fluid-structure coupling surface. The accuracy of the theoretical predictions is checked against finite element results with good agreement achieved. The results show that not the physical parameters with variation of temperature but the thermal moments and membrane forces, cause the buckling phenomenon. It is noted that buckling phenomenon occurs not only in uniform temperature field but also in graded temperature distribution filed. The mechanism analysis about modal snap-through and losing phenomenon indicates that thermoacoustic loadings will affect the stiffness matrix and mass matrix of structure. With the increase of temperature, the lower modes of the plate are lost, the higher modes appear in advance, and the losing phenomenon occurs in accordance with the order.

14

Semi-analytical modelling of multilayer continuous systems nonlinear dynamics

Koziol P., Pilecki R.

Archives of Civil Engineering

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2020

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Vol. 66, nr 2

165--178

EN

Problems concerning structures dynamics are being one of most important subjects in recent investigations associated with railways constructions. The need of modelling of such structures and their behaviour prediction leads to necessity of seeking new approaches, mainly due to highly increasing speeds of vehicles and traffic intensity. Comparative studies carried out on experimental data, measurements and theoretical research show that models based on multi-layered approach supported by semi-analytical approximations of solutions can give new insight into undertaken analyses. More detailed consideration of roads components and their physical properties, along with application of effective estimations allowing to avoid numerical instabilities linked with extremal dynamic variations, can be important tools in obtaining new solutions both, theoretical and engineering. This paper briefly presents a number of multilayer railway track models, with special emphasis on nonlinear track properties. Existing analytical and semi-analytical solution methods are presented with main advantages of new approaches. The theoretical double-beam system with two nonlinear layers is solved and computational examples are presented along with possibility of their transition to other multilayer structures analysis.

PL

Problemy dynamiki konstrukcji stanowią jeden z najbardziej istotnych działów współczesnych badań związanych z konstrukcjami kolejowymi. Potrzeba modelowania takich konstrukcji oraz przewidywania ich dynamicznych oddziaływań prowadzi do konieczności poszukiwania nowych rozwiązań, głównie z powodu rosnących prędkości pojazdów i intensywności ruchu. Studia porównawcze prowadzone zarówno w ramach prac eksperymentalnych, pomiarowych, jak i teoretycznych rozważań pokazują, że modele wielowarstwowe w połączeniu z metodami semianalitycznymi mogą dać nowe spojrzenie na wyniki dotychczasowych analiz. Dokładniejsza analiza elementów drogi oraz ich fizycznych właściwości, razem z zastosowaniem efektywnych estymacji i aproksymacji pozwalających uniknąć numerycznych niestabilności spowodowanych ekstremalnymi dynamicznymi zmianami układów, mogą być ważnymi narzędziami służącymi otrzymaniu nowych rozwiązań, zarówno teoretycznych jak i inżynierskich. Artykuł ten prezentuje w skrócony sposób wybrane modele wielowarstwowe drogi kolejowej, ze szczególnym uwzględnieniem jej nieliniowych właściwości. Zostały omówione istniejące rozwiązania analityczne i semi-analityczne, ze wróceniem uwagi na korzyści płynące z ich zastosowania. Teoretyczny model belki podwójnej został rozwiązany. Pokazano przykłady obliczeniowe wraz z omówieniem możliwości ich adaptacji do analizy innych struktur wielowarstwowych. Dotychczas opublikowane prace zawierają interesujące wyniki semi-analityczne związane z założeniem nieliniowej sztywności elementów konstrukcji typu belka-podłoże. Modele jednowarstwowy i dwuwarstwowy zostały szczegółowo przeanalizowane przy założeniu nieliniowej sztywności podłoża, przy użyciu semi-analitycznej metody opartej na aproksymacjach falkowych połączonych z dekompozycją Adomiana. Modele te zostały również poddane walidacji poprzez porównanie wyników z pomiarami wykonanymi na rzeczywistym torze kolejowym, pokazujące wysoką zgodność rezultatów w zakresie drgań pionowych drogi kolejowej dla różnych zbiorów parametrów i prędkości pojazdów.

15

Macroscopic dynamic response of mechanical systems involving composites and effect of inner structure on damping properties

Murčinková Zuzana

Mechanik

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2019

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R. 92, nr 4

288--291

EN

The paper deals with relation between inner structure of the machine and the composite material used in it and macroscopic dynamic response. It presents the experimental results of testing the relation between inner composite material structure and damping properties presented by logarithmic decrement quantity. Moreover, the paper provides the case study of application the composite material layered structure to the flexographic printing machine and results of that applications presented by printing speed.

PL

W artykule omówiono zależność między wewnętrzną budową maszyny i wykorzystanego w niej materiału kompozytowego a makroskopową odpowiedzią dynamiczną układu. Przedstawiono wyniki badań zależności między wewnętrzną strukturą materiału kompozytowego a właściwościami tłumiącymi wyrażonymi przez logarytmiczny dekrement tłumienia. Ponadto zaprezentowano studium przypadku – zastosowanie kompozytu warstwowego w konstrukcji drukarki fleksograficznej oraz wpływ tego rozwiązana na uzyskiwaną prędkość druku.

16

Influence of the damping effect on the dynamic response of a plate

Borkowski Łukasz

Journal of Theoretical and Applied Mechanics

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2019

|

Vol. 57 nr 1

263--272

EN

The subject of the research is analysis of the influence of the damping effect on the dynamic response of a plate. During the tests, the areas of dynamic stability and instability for the plate with and without damping are compared. Besides, exact analysis of the nature of the solution by applying criteria such as phase portraits, Poincar´e maps, FFT analysis, the largest Lyapunov exponents are carried out and found.

17

Effect of pulse shape and duration on dynamic response of a forging system

Trąbka Arkadiusz

Acta Mechanica et Automatica

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2019

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Vol. 13, no. 4

226--232

EN

Forging hammers are machines whose operation causes negative effects both at the place of their foundation (the soil settlement) and in their surroundings (e.g., vibrations propagating to the other devices, noise, etc.). Knowledge of the parameters characterizing the time history of the force that arises as a result of impact of a ram on a shaped material is of fundamental importance for the correct analysis of both the structure of the hammer and its impact on the surroundings. In the paper, the effect of the shape and duration of a pulse load on the dynamic response of a hammer-foundation forging system was assessed. An analytical method of description of the forces that arise as a result of impact of the ram on the forged material, using different forms of pulses was presented. The forces defined in this way as loads in a mathematical model of three degrees of freedom forging system were used. The equations of motion derived from d'Alembert's principle were solved numerically in the Matlab program. The analyses for eight forms of the pulse loads with the same pulse sizes but different durations were performed. The results in the graphs were presented. It was found, among other things, that a greater impact on the maximum displacement, velocity and acceleration of each component of the hammer-foundation system as well as on the maximum forces transmitted to the soil has the duration of a pulse than its shape.

18

Dynamic behavior of a high-rise building under seismic loads for different bearing frame types

Sakharov V., Lytvyn O., Pidlutskyi V.

Civil and Environmental Engineering Reports

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2018

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Vol. 28, no. 4

180--189

EN

Paper presents the results of dynamic behavior analysis of a high-rise building under seismic loads as part of the “base-foundation-building” system. Analysis covers different types of reinforced concrete construction with girder frame and non-girder frame. Using modal analysis, paper presents differences in mode shapes and frequencies caused by the presence or absence of girders. Paper also demonstrates variations in the stress-strain state for the vertical bearing structures under the seismic load for different frame types.

PL

W artykule zostały przedstawione wyniki analizy dynamicznej zachowania się wielokondygnacyjnego budynku wysokiego pod obciążeniem sejsmicznym jako układu "podłoże gruntowe – fundament – budynek". Analiza obejmuje różne rodzaje konstrukcji szkieletowych z betonu zbrojonego o ramie nośnej z belkami wzmocnienia i bez nich. Wykorzystując analizę modalną, w artykule podane różnice we własnych formach i częstotliwościach dla różnych rodzajów szkieletu budynku. W prace również zostały wykazane zmiany w rozkładzie naprężeń w pionowych konstrukcjach nośnych budynku pod obciążeniem sejsmicznym w zależności od rodzaju szkieletu budynku.

19

The dependency of the dynamic response of a two mast bucket wheel excavator superstructure on the counterweight mass and the degree of Fourier approximation of the digging resistance

Gnjatovic N., Bosnjak S., Stefanovic A.

Archives of Mining Sciences

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2018

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Vol. 63, no. 2

491--509

EN

Sensitivity analysis of the dynamic response of both the designed and the actual models of a slewing superstructure with two masts to the variation of the counterweight mass and the degree of accuracy of the approximation polynomials of the digging resistance was conducted in the paper. Spatial reduced dynamic models of the bucket wheel excavator SchRs 1600 were used as a basis for the presented investigations. Based on the comparative analysis of the calculation results, the following conclusions were drawn: (a) mass of the counterweight has a significantly higher influence on the maximum intensities of accelerations of the referent points than on the spectrum of natural frequencies, (b) the accuracy of approximations of the digging resistance and the maximum values of accelerations differ by an order of magnitude, for the approximation trigonometric polynomial of the same number of harmonics.

PL

W pracy przeprowadzono analizę wrażliwości odpowiedzi dynamicznej modelu obliczeniowego i rzeczywistego konstrukcji obrotowej koparki z dwoma masztami na zmiany masy przeciwciężaru oraz zmiany stopnia dokładności przybliżania wielomianów określających opory urabiania. W pracy wykorzystano przestrzenne zredukowane modele dynamiczne koparki kołowej SchRs1600. Na podstawie analizy porównawczej wyników obliczeń wyciągnięto następujące wnioski: (a) masa przeciwciężaru ma znacznie większy wpływ na maksymalne natężenie przyspieszeń w punktach odniesienia niż na zakres częstotliwości własnych; (b) dokładność przybliżenia oporów urabiania i maksymalne wielkości przyspieszeń różnią się o rząd wielkości dla procedury aproksymacji wykorzystującej wielomian zawierający funkcje trygonometryczne, o tej samej liczbie harmonicznych.

20

Dynamic response of a steel pipeline with bolted connections to a mining shock obtained with the submodeling technique

Boroń P., Dulińska J.

Technical Transactions

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2017

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Vol. 6(114)

71--83

EN

In this paper, the dynamic response of an overground steel pipeline to a real mining shock is presented. The submodeling method was used in the calculation. Firstly, time history analysis of a simplified beam model of the pipeline (a global model) was conducted. Secondly, the 3D model of a part of the structure over the support was created (a submodel). The submodeling analysis allowed obtaining stress distribution in the bolted connection of the pipeline segments.

PL

W artykule przedstawiona została analiza odpowiedzi dynamicznej naziemnego gazociągu na rzeczywisty wstrząs górniczy. W obliczeniach zastosowano technikę submodelingu. W pierwszym etapie przeprowadzono obliczenia uproszczonego, belkowego modelu całego gazociągu (model globalny). W drugim etapie zastosowano model 3D fragmentu konstrukcji, obejmujący odcinek gazociągu nad podporą (submodel). Analiza z zastosowaniem techniki submodelingu pozwoliła na dokładne rozeznanie pracy złącza gazociągu oraz na określenie rozkładu naprężeń w kołnierzu i śrubach złącza.