Wyniki wyszukiwania - BazTech

1

Nośność i morfologia uszkodzeń połączeń ścian wykonanych z ABK poddanych ścinaniu ze zginaniem

Galman Iwona

Przegląd Budowlany

|

2024

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R. 95, nr 1-2

67--72

PL

W pracy przedstawiono wyniki badań doświadczalnych 4 serii (łącznie 24 modeli badawczych) połączeń wzajemnie prostopadłych ścian wykonanych z elementów murowych z autoklawizowanego betonu komórkowego (abk) poddanych ścinaniu ze zginaniem. Badano modele referencyjne składające się z dwóch ścian połączonych prostopadle tradycyjnym wiązaniem murarskim oraz modele o takiej samej geometrii, ale ze zmodyfikowanym sposobem łączenia - z wykorzystaniem różnych, dostępnych na rynku typów łączników (blach, kratowniczek). Dokonano analizy dotyczącej nośności oraz morfologii i mechanizmu uszkodzeń modeli.

EN

The paper presents the results of experimental tests of 4 series (a total of 24 research models) of mutually perpendicular joints of walls made of autoclaved aerated concrete (aac) masonry elements subjected to shearing with bending. Reference models consisting of two walls connected perpendicularly with a traditional masonry bond and models with the same geometry, but with a modified method of connection - using various types of connectors available on the market (plates, trusses) were tested. An analysis of the load capacity, morphology and damage mechanism of the models was made.

2

Innovative thrust vectoring system with moveable jet vanes integrated with a moveable diffuser – Measurement and analysis of selected nozzle performance parameters

Nocoń Łukasz Krzysztof, Grzyb Marta, Szmidt Piotr, Nowakowski Łukasz Marian

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2024

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Vol. 72, nr 2

art. no. e148444

EN

The aim of the study described herein was to design, construct and test a demonstrator of a system to control the direction of the resultant thrust vector of a rocket motor to be used in short range anti-tank missiles with a mass of up to 15 kg. The novelty of the system is that the direction of the resultant thrust vector is manipulated by means of moveable jet vanes integrated with a moveable nozzle diffuser through telescopic connectors. The technology demonstrator was built using different materials and different manufacturing processes. The first versions were 3D printed from plastic materials. Minor modifications to the design were made at an early stage. The final version had the main components made of aluminum using CNC machining. The system, with and without jet vanes, was tested on a specially developed test rig equipped with a multi-axis sensor to measure forces and torques. The nozzle performance parameters measured and analyzed in this study were the components of the thrust vector, the moments and the effective vectoring angle. The findings show that the experimental data are in good agreement with the results of earlier simulations and that the demonstrator is fully operational.

3

Analysis of a crash on a vehicle system by adjusting appropriate input parameters to manage energy absorption capacity for enhancing passenger safety

Dhamone Sagar Parashuram, Padmakumar Arunkumar

Acta Innovations

|

2023

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no. 50

5--17

EN

The aim of the research is to develop a front bumper system that absorbs maximum impact energy as compared to the current bumper available in the market, Bumper design is based on increasing the area of the crumping zone to slow down the collision and observe the impacts taking place at the time of jerks and reduces the percentage of damage. To develop the system, the number of load cases tested numerically in passive safety simulation has increased significantly in recent years. The variety of applications may be divided into three main topics: structural crashworthiness of the whole car, passenger protection, and crashworthiness of components. Present theories and practices. To absorb impact, the front bumper of the car uses a spring-loaded system that is installed between the bumper and the support for the chassis structure. This system is made of metal and serves as the bumper's structural foundation. A honeycomb structure is being added to the bumper as a composite material together with a layer of galvanized iron as it is being created in this manner, which increases strength while weighing less. This arrangement design is suitable for psychoacoustics, varying velocity explicit analysis is performed with the approach of finite element analysis, experimental testing is carried out for the validation of the value and advanced manufacturing methods are implemented with statistical results, and one of the cheapest systems is developed as compared to the current bumper systems.

4

Developed jet-centrifugal spray devices: experimental testing to establish the possibility of their application in plants spraying technologies

Vambol S., Khan N. A., Khan A. H., Kiriyenko M., Borysova L., Taraduda D., Zakora A., Bilotserkivska N.

Journal of Achievements in Materials and Manufacturing Engineering

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2020

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Vol. 102, nr 1

30--41

EN

Purpose: Experimentally substantiate the possibility of using the developed jet-centrifugal spraying device in plants spraying technologies. Design/methodology/approach: Many years of experience in creating spraying devices for solving practical problems in various industries made it possible to propose a design diagram of a single-phase jet-centrifugal spraying device. The tests were aimed at achieving device characteristics that are acceptable for use in plants spraying technologies such as jet coverage distance, droplet size and droplet deposition area (spray diameter). For this a several tests series with different design parameters was done. Before testing, the tightness of the device body was checked (the holding time under a pressure of 1 MPa is not less than 2 minutes). Findings: Based on the obtained jet coverage distance, droplet size and droplet deposition area, the developed spray device of some modifications can be used in plants spraying technologies. However, it is necessary to determine the quality of the spray device according to the BCPC classification; the device should be tested with some insecticides, fungicides and in plants spraying technologies to develop recommendations for their use. Research limitations/implications: The influence of design features of developed jetcentrifugal spray device on the jet coverage distance, droplet size and droplet deposition area was studied. Practical implications: The results obtained are useful in the field of improving national plants spraying technologies in order to improve the quality of the plant protection agent application and reduce the loss of the drug into the environment. Originality/value: To ensure maximum efficiency the proposed design of the jetcentrifugal spray device can be upgraded directly by the farmer by installing interchangeable nozzles that are attached with a union nut. Replaceable nozzles have different diameters and modifications and can be selected depending on the required jet coverage distance and spraying dispersion according to the current environmental conditions.

5

Comparative analysis of energy performance of squirrel cage induction motor, line-start synchronous reluctance and permanent magnet motors employing the same stator design

Lyskawinski Wieslaw

Archives of Electrical Engineering

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2020

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Vol. 69, nr 4

967--981

EN

The paper presents research on the development of a line-start synchronous reluctance motor (LSSynRM) and line-start permanent magnet synchronous motor (LSPMSM) based on components of a mass-produced three-phase low-power squirrel cage induction motor (IM). The aim of the research was to modify the squirrel cage rotor structure for which the best functional parameters characterizing the steady state of the LSSynRM and LSPMSM were obtained, while meeting the additional requirements for asynchronous start-up. Field-circuit models of the LSSynRM and LSPMSM have been developed in the professional finite element method (FEM) package, MagNet, and applied in the design and optimization calculations of the considered machines. Experimental testing on the designed LSSynRM and LSPMSM prototypes were carried out. The obtained results were compared with the performance of the reference IM. The conclusions resulting from the comparative analysis of these three motors are given and proposals for further work are discussed.

6

Rocking of freestanding objects: theoretical and experimental comparisons

Gesualdo A., Iannuzzo A., Minutolo V., Monaco M.

Journal of Theoretical and Applied Mechanics

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2018

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Vol. 56 nr 4

977--991

EN

The methodical study of safeguard of artistic heritage and other devices subjected to earthquake and, in general, to time-dependent forces has considerably spreaded in the last years, thus increasing researchers’ interest in problems concerning motions of rigid objects simply supported on a base plane. The behaviour of piece of equipments, statues, storage tanks, or even tall buildings has been in fact studied as that of rigid bodies with relation to different base excitations. In some cases, the possibility of influencing the quality of motion can be a strong tool to reduce vulnerability, like in the cases in which rocking motion is to be avoided and sliding motion is welcome. This paper focuses the attention on this last problem. This is the same large class of both non-structural and structural elements that can lose their functionality because of earthquake motions. The results of numerical modelling of sliding and rocking motion in presence of both different excitations and mechanical parameters are presented and compared with experimental data performed by the authors. The results developed are in good agreement with the laboratory tests, and this assures the reliability of both the analytical procedure and the determination of the parameters involved.

7

Odporność na skręcanie elementów z betonu samozagęszczającego się zbrojonego włóknami stalowymi i zawierającego kruszywo z recyklingu

Sai Nitesh K. J. N., Rao S. V., Kumar P. R.

Cement Wapno Beton

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2018

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R. 21/83, nr 4

259--276

PL

W artykule przedstawiono wyniki badań właściwości mechanicznych betonu samozagęszczalnego, w którym 25% kruszywa grubego zastąpiono kruszywem z odpadowego betonu. W betonie zastosowano 0,5% objętościowy dodatek włókien stalowych o współczynniku kształtu 50, 70 oraz 100 z haczykowatymi zakończeniami. Przygotowano 32 belki z betonu samozagęszczalnego oraz wibrowanego o wytrzymałościach 50 MPa oraz 80 MPa z kruszywem naturalnym oraz z odpadowego betonu. Uzyskane wyniki pozwoliły stwierdzić, że beton samozagęszczalny miał lepsze właściwości związane ze skręcaniem, takie jak maksymalny moment obrotowy, kąt skrętu, sztywność skrętna i odporność na skręcanie w porównaniu z betonem wibrowanym zarówno z kruszywem naturalnym jak i z odpadowego betonu, zawierającym dodatek włókien. Lepsze właściwości uzyskano dla elementów o współczynniku kształtu stosowanych włókien wynoszącym 70 w przypadku obu rodzajów betonów w porównaniu do próbek o współczynniku kształtu wynoszącym 50 i 100. Modelowanie metodą elementów skończonych przeprowadzono dla wszystkich belek stosując oprogramowanie ATENA-GID. Zgodność pomiędzy wynikami doświadczalnymi, a wynikami uzyskanymi za pomocą modelowania MES uznano za zadowalającą.

EN

In the present study, self compacting concrete beams with recycled coarse aggregate as 25% replacement of total coarse aggregate, were tested at varying aspect ratio of 50, 70 and 100 of hook end steel fiber for constant fiber content of 0.5 % by volume of concrete and compared with vibrated concrete. A total of 32 beams were cast with 50MPa and 80MPa self compacting and vibrated concrete with natural and recycled coarse aggregate. It can be observed from the study that there is a significant increase in all torsional properties like ultimate torque, angle of twist, torsional stiffness, torsional toughness in self compacting compared to vibrated concrete for both natural and recycled coarse aggregate with the addition of fibers in SCC. Better performance was observed in members with fiber aspect ratio 70 in both concretes compared to lower [50] and higher aspect ratio [100]. Finite element modelling was done based on ATENA-GID software for all the beams and results were compared with experimental test results. The correlation between experimental and FEM modelling results was found satisfactory.

8

Evaluation of large-scale load-carrying structures of machines with the application of the dynamic effects factor

Pietrusiak D.

Eksploatacja i Niezawodność

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2017

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Vol. 19, no. 4

542--551

EN

Load-carrying structures of large-scale machines are their key element, mainly due to their size which renders them virtually impossible to replace during operation. Such structures are used for example in the heavy industry, mining, bulk material handling or rock processing. This article presents the most important results of recent research into dynamic loads and design of such structures. Based on these results the article introduces the author's method of evaluating load-carrying structures with the application of the dynamic effects factor and describes the effects of the application of this method.

PL

Ustroje nośne maszyn wielkogabarytowych są ich kluczowym elementem, ze względu na ich rozmiar a tym samym niemalże brak możliwości wymiany w trakcie eksploatacji. Ustroje tego typu stosowane są np. w przemyśle wydobywczym, przeładunkowym czy przetwórstwa skalnego. W artykule zebrano i zaprezentowano wyniki najważniejszych badań ostatnich lat dotyczących obciążeń dynamicznych oraz projektowania tego rodzaju obiektów. Na tej podstawie przedstawiono autorską metodę oceny ustrojów nośnych z zastosowaniem współczynnika obciążeń zastępczych oraz efekty jej stosowania.

9

Prefabrykowane nadproża z autoklawizowanego betonu komórkowego – badania i analizy teoretyczne

Drobiec Ł., Jasiński R., Mazur W.

Cement Wapno Beton

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2017

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R. 21/83, nr 5

399--413

PL

Wyniki badań układów nadproże-mur wykazały, że średnia wartość siły niszczącej elementów z trzema warstwami detali murowych była większa o 3% od średniej siły niszczącej modeli z pięcioma warstwami elementów murowych i o 99% od średniej siły niszczącej z jedną warstwą elementów murowych. Zniszczenie nadproży, badanych jako belki swobodnie podparte oraz jako belki z nadbudowanym murem i belką żelbetową imitująca wieniec, było inne. Nadproża badane jako belki swobodnie podparte traciły możliwość przenoszenia obciążeń w wyniku utraty nośności zakotwienia zbrojenia w strefie podporowej, czego w zasadzie nie obserwowano w badaniach nadproży wraz z murem. W przeprowadzonych badaniach uwidocznił się wpływ utwierdzenia nadproża na podporze co potwierdzają wyniki analizy numerycznej. Wyniki badań pokazują również, że wraz ze wzrostem wysokości muru malały ugięcia określone przy największej sile. W efekcie zniszczenie ściany nie jest sygnalizowane wyraźnym ugięciem nadproża, wykluczając możliwość działań zabezpieczających.

EN

On the basis of test results of lintel-brickwork system, it was found that the average value of the destructive force for elements with 3 layers of masonry units was higher than the destructive force for elements with 5 layers of masonry units by 3%, and higher than the destructive force for elements with 1 layer of masonry units by 99%. The destruction of tested lintels as freely supported beam and beam with brickwork above, and reinforced concrete beam simulating the tie was different. The lintels tested in the system of freely supported beam were not able to transmit loads as they lost anchoring capacity of reinforcement in the support zone. The performed tests highlighted the impact of lintel restraint to the support, which was also confirmed by numerical analysis. The test results also demonstrate the decrease in deflections determined at the greatest force along with the increased height of brickwork. As a result, brickwork destruction was not signaled by clear deflection of the lintel, which excluded possible preventive measures.

10

Digital Image Correlation and nanoindentation in evaluation of material parameters of cancellous bone microstructure

Kokot G., Skalski K., Makuch A., Ogierman W.

Archives of Materials Science and Engineering

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2017

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Vol. 83, nr 1

10--16

EN

Purpose: Purpose of this paper is to present the possibilities of the application of the two methods: Digital Image Correlation and nanoindentation in porous bone tissues testing. Firstly, as a tool in the evaluation process of material parameters for porous microstructures, such as bone tissues or other foams and, secondly, as validation and verification tools for finite element analysis of bone or foams structures. Those methods are helpful when the high accuracy of the mechanical parameters of porous microstructures is required. Design/methodology/approach: Two methods: Digital Image Correlation (DIC) and nanoindentation are used as an efficient approach in the evaluation process of material parameters or constitutive relationship of porous structures like bone tissues. Digital image correlation enlarges the accuracy of classical mechanical tests and the nanoindentation allows to look inside the microstructure. Findings: The proposed methods were found to be effective in experimental testing and material parameters evaluation process of some special materials. Among them are porous structures, such as bone tissue. Additionally, the DIC is an excellent tool for finite element model validation and results verification. Practical implications: The presented method based on the combination of the Digital Image Correlation and nanoindentation presents new possibilities in material testing fields, material behavior and parameters evaluation. They have great advantages, among others, in the field of testing of porous bone structure or determining the mechanical parameters of bone tissue. Originality/value: The paper presents methods for testing the complicated porous bone structures: evaluating mechanical behavior of the whole structure and evaluating mechanical properties of the single element of the structure. The mechanical parameters of human cancellous bone structures are presented as the preliminary research results.

11

The influence of superstructure vibrations on operational loads in the undercarriage of bulk material handling machine

Pietrusiak D., Smolnicki T., Stanńco M.

Archives of Civil and Mechanical Engineering

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2017

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Vol. 17, no. 4

855--862

EN

This article presents research on the correlation between vibrations of the ŁZKS 1600 stacker-reclaimer superstructure and the harmonic changes in loads in undercarriage supports. Investigations are focused on the change in center of gravity location caused by superstructure vibrations and its influence on loads acting on the elements of the undercarriage. The presented research and analysis of results indicate a clear correlation between dynamic behavior of the superstructure and the changes in loads acting on the undercarriage. It was shown that the harmonic nature of the changes in these loads is derived from the global vibrations of the superstructure, which cause a dynamic change in the position of the center of mass.

12

Experimental investigation of an energy harvesting rotary generator-MR damper system

Sapiński B.

Journal of Theoretical and Applied Mechanics

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2016

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Vol. 54 nr 3

679--690

EN

The study investigates an energy harvesting system utilising rotary motion. The system has three components: a rotary MR damper to vary the damping characteristics, a rotary power generator (energy extractor) producing electrical power, and a conditioning electronics unit to interface directly with the damper and the generator. The objective of the study is to examine the system performance through experiments. The paper outlines the structure of the damper and the generator, provides selected results of examination of the system components and the whole system under idle run and under load for the assumed speed range. The results demonstrate that the system is adaptable to external excitations, does not require an extra power supply and provides a smart solution with potential applications to rotary motion control.

13

The effects of strain amplitude and localization on viscoelastic mechanical behaviour of human abdominal fascia

Kirilova-Doneva M., Pashkouleva D., Kavardzhikov V.

Acta of Bioengineering and Biomechanics

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2016

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Vol. 18, no. 4

127--133

EN

Purpose: The purpose of the paper is to examine and compare the viscoelastic mechanical properties of human transversalis and umbilical fasciae according to chosen strain levels. Methods: A sequence of relaxation tests of finite deformation ranging from 4 to 6% strain with increment 0.3% was performed at strain rate 1.26 mm/s. Initial and equilibrium stresses T0, Teq, initial modulus E and equilibrium modulus Eeq, reduction of the stress during relaxation process ΔT, as well as the ratio (1 – Eeq /E) were calculated. Results: The range in which parameters change their values are (0.184–1.74 MPa) for initial stress, (0.098–0.95 MPa) for equilibrium stress, (43.5–4.6 MPa) for initial modulus E. For Eeq this interval is (23.75–2.45 MPa). There are no statistically significant differences between the values of these parameters according to localization. The differences in viscoelastic properties of both fasciae are demonstrated by reduction of the stress during relaxation process and ratio (1 – Eeq /E). The values of ΔT and (1 – Eeq /E) ratio for umbilical fascia are significantly greater than that of fascia transversalis. An increase of 2% in strain leads to change of the normalized relaxation ratio of fasciae between 28%–66%. There is a weak contribution of viscous elements in fascia transversalis samples during relaxation, while in umbilical fascia the contribution of viscous component increases with strain level to 0.66 at 5.3% strain. Conclusions: This study adds new data for the material properties of human abdominal fascia. The results demonstrate that in chosen range of strain there is an influence of localization on visco-elastic tissue properties.

14

Wpływ ciśnienia zasilania na zmianę parametrów pracy zasysacza liniowego Z4

Wąsik W., Drzymała T., Chudy P.

Logistyka

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2015

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nr 4

8482--8493, CD2, cz. 5

PL

Do wytworzenia piany na miejscu działań ratowniczo – gaśniczych niezbędny jest specjalistyczny sprzęt, którego najważniejszym elementem umożliwiającym zassanie i wymieszanie środka pianotwórczego z wodą jest strumienica czyli urządzenie przeznaczone do zasysania i podnoszenia płynów albo do mieszania płynów z ciałami stałymi. Mimo nowej technologii, zasysacze liniowe poprzez swoją niezawodną konstrukcję, wciąż stanowią podstawowe wyposażenie samochodów gaśniczych. W referacie omówiono przeprowadzone badania dla wybranego zasysacza liniowego Z4, aktualnie stosowanego w ochronie przeciwpożarowej oraz stawiane mu wymagania normowe. Na podstawie przeprowadzonych badań wyznaczone zostały charakterystyki teoretyczne, jak również charakterystyki rzeczywiste (doświadczalne) badanego sprzętu oraz sformułowano wnioski końcowe z przeprowadzonych badań.

EN

In the manufacture of the foam on the spot relief activities-for specialized equipment is needed, which is the most important element for pull and mixing foam concentrate with water is a spotlight or a device designed to suck in and picking up liquids or for mixing liquids with solid. Despite new technology, in-line foam concentrate inducers through its reliable design, still constitute the basic equipment of firefighting vehicles. Research of flow characteristics of selected in-line foam concentrate inducer Z4 used currently in fire protection and its comparison with standard requirements are discussed in the paper. On the basis of the studies carried out either theoretical or real characteristics of tested devices are presented. A comparative analysis of the tested ejector and the final conclusions are included at the end of the paper.

15

Ocena podstawowych charakterystyk pracy pomp strumieniowych stosowanych w pożarnictwie

Drzymała T., Wąsik W., Chudy P., Rózga Ł.

Logistyka

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2015

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nr 4

7391--7403, CD2

PL

Prosta konstrukcja strumienic i łatwość ich wykonania zapewniły im szeroki zakres zastosowania w technice. Podstawowymi rodzajami strumienic cieczowych stosowanych w ochronie przeciwpożarowej są wysysacze (wypompowywanie wody z zalanych pomieszczeń) i zasysacze liniowe (wytwarzanie wodnego roztworu środka pianotwórczego). W referacie omówiono badania dla wybranych pomp strumieniowych (wysysaczy) aktualnie stosowanych w ochronie przeciwpożarowej oraz stawiane im wymagania normowe. Na podstawie przeprowadzonych badań wyznaczone zostały charakterystyki teoretyczne, jak również charakterystyki rzeczywiste (doświadczalne) badanego sprzętu. Przeprowadzono analizę porównawczą badanych pomp strumieniowych oraz sformułowano wnioski końcowe z przeprowadzonych badań.

EN

Simple design and ease-of-implementation of them provided their spotlights a wide range of applications in technology. The basic types of liquid ejectors used in fire protection are ejector pumps (pumping out water from flooded rooms) and in-line foam concentrate inducers (manufacture of aqueous solution foam). Research on flow characteristics of selected ejector pumps used currently in fire protection and its comparison with standard requirements are discussed in the paper. On the basis of the studies carried out either theoretical or real characteristics of tested devices are presented. A comparative analysis of the tested ejector pumps and the final conclusions are included at the end of the paper.

16

Analysis, design and applications of rotational friction dampers for seismic protection

Mualla I., Belev B.

Czasopismo Inżynierii Lądowej, Środowiska i Architektury / Journal of Civil Engineering, Environment and Architecture

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2015

|

z. 62, nr 4

335--346

EN

The paper introduces the basic types of damping devices and summarizes the benefits of implementing supplemental damping systems for seismic protection of buildings and other structures. A novel damper device based on the rotational friction hinge concept invented by the first author is described. The slip capacity of the device and its energy dissipation capacity can be easily increased by adding more layers of steel plates and friction pads. The experimental evaluation of the original damper unit was first carried out in DTU, Denmark under displacement and forcing frequency control. The friction pads were made from advanced material capable of sustaining up to 400 cycles without property degradation. In 2001, an international team including the authors conducted intensive research program on a three-storey building equipped with rotational friction dampers at the large-scale shake-table testing facility of the NCREE, Taiwan. The performance of the damped structure was examined for 14 cases of seismic input with peak ground acceleration (PGA) varying from 0.05g to 0.30g. The testing demonstrated the remarkable efficiency of the damping system for reducing the lateral displacements and interstorey drifts of the test building. Nonlinear time-history analyses were used for predicting the dynamic response of the structure and selecting adequate damper capacities. A few representative applications of RFDs for seismic protection of buildings and facilities in Europe and Japan are given which demonstrate the reliability of the devices and their most typical arrangements within new and existing structures. It is concluded that the displacement-dependent dampers such as friction and metallic are a powerful and nonexpensive engineering tool for solving vibrational problems both in new and existing structures.

PL

W artykule przedstawiono podstawowe typy urządzeń tłumiących i podsumowano korzyści z zastosowania dodatkowych systemów tłumiących w celu sejsmicznej ochrony budynków i innych konstrukcji. Opisano nowatorskie urządzenie tłumiące, wymyślonego przez pierwszego autora, bazujące na koncepcji tarcia obrotowego w przegubie. Zdolność do poślizgu urządzenia i jego zdolność do dyssypacji energetycznej może być łatwo zwiększana przez dodawanie kolejnych warstw blach stalowych i podkładek ciernych. Doświadczalna ocena prototypu urządzenia tłumiącego, pod kątem przemieszczeń i częstości drgań wymuszonych, została przeprowadzona w DTU, w Danii. Podkładki cierne zostały wykonane z zaawansowanego technologicznie materiału zdolnego wytrzymać do 400 cykli obciążenia bez degradacji swoich właściwości. W 2001 roku międzynarodowy zespół, w skład którego wchodzili również autorzy, przeprowadził intensywny program badawczy na trzykondygnacyjnym budynku, wyposażonym w tłumiki obrotowo cierne na stole wibracyjnym dużej skali obiekcie testowym NCREE, na Tajwanie. Przygotowaną Konstrukcję z tłumikami badano dla 14 przypadków obciążeń sejsmicznych ze szczytowymi wartościami przyśpieszenie ziemi (PGA) w granicach 0.05 g do 0.30 g. Badania wykazały niezwykłą efektywność systemu tłumiącego w redukcji giętnych przemieszczeń i przesunięć międzykondygnacyjnych w badanym budynku. Do określenia odpowiedzi dynamicznej konstrukcji i dobrania odpowiedniej mocy tłumika zostały użyte nieliniowe analizy przebiegów czasowych. Zaprezentowano kilka przykładowych zastosowań RFDs w celu sejsmicznego zabezpieczenia budynków i obiektów w Europie i Japonii, wykazując niezawodność urządzeń i ich najbardziej typowe układy wewnątrz nowych i istniejących budynków. Na koniec stwierdzono, że tłumiki związane z przemieszczeniami takimi jak tarcie są potężnym i niedrogim narzędziem inżynierii dla rozwiązywania problemów drgań zarówno w nowych jak i istniejących konstrukcjach.

17

Split Hopkinson Pressure Bar impulse experimental measurement with numerical validation

Baranowski P.

Metrology and Measurement Systems

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2014

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Vol. 21, nr 1

47--58

EN

Materials and their development process are highly dependent on proper experimental testing under wide range of loading within which high-strain rate conditions play a very significant role. For such dynamic loading Split Hopkinson Pressure Bar (SHPB) is widely used for investigating the dynamic behavior of various materials. The presented paper is focused on the SHPB impulse measurement process using experimental and numerical methods. One of the main problems occurring during tests are oscillations recorded by the strain gauges which adversely affect results. Thus, it is desired to obtain the peak shape in the incident bar of SHPB as “smooth” as possible without any distortions. Such impulse characteristics can be achieved using several shaping techniques, e.g. by placing a special shaper between two bars, which in fact was performed by the authors experimentally and subsequently was validated using computational methods.

18

Analysis of a conical sleeve with pivot joint loading of axial force

Andrzejuk A., Skup Z., Zalewski R.

Journal of Theoretical and Applied Mechanics

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2014

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Vol. 52 nr 2

345--358

EN

The paper presents theoretical and experimental studies of energy dissipation in a model of a conical sleeve-pivot joint. Energy dissipation between cooperating surfaces of a friction pair including structural friction, elastic and frictional effects between its elements and Lame’s problem are taken into account. A comparative analysis was conducted to compare the theoretical results obtained from numerical simulations and direct experimental data acquired from the MTS testing machine. The analysis of the influence of geometrical and material parameters, external loading on the dissipation of energy is presented too. This paper shows an outline of theoretical considerations, the method for conducting tests as well as selected comparative results.

19

Study on computational methods applied to modelling of pulse shaper in split-Hopkinson bar

Baranowski P., Janiszewski J., Malachowski J.

Archives of Mechanics

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2014

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Vol. 66, nr 6

429--452

EN

The paper presents a possibility of numerical modelling of a copper shaper utilized in an SHPB device with additional attention paid to the proper bar-shaper interaction simulation. The pulse shaper was modelled with the use of three methods available in the commercial code, i.e., applying typical finite Lagrangian elements, meshless smoothed particle hydrodynamics (SPH) method and multi- material arbitrary Lagrangian–Eulerian (MM-ALE) formulation. Additionally, the authors performed a mesh (particles) sensitivity study and the assessment of its influence on the obtained incident pulse characteristics. Consequently, the results obtained from all numerical analyses were compared and validated with the experimental ones with a particular attention given to the shape of the incident pulse and copper shaper deformation. The paper describes also the investigation of a relationship between the contact (coupling) force and the impulse shape.

20

Evaluation of mechanical properties of soft magnetic materials for axial flux permanent magnet synchronous machines

Praunseis Z., Virtič P.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 2b

35--37

EN

Accurate determination of real material mechanical properties is important for safe servicing of energy components. The aim of the paper is systematic experimental approach for determination of mechanical properties of high strenght low alloyed steels and mild carbon steel in the rolling, thickness and width direction.

PL

W artykule przedstawiono metodę eksperymentalnej i systematycznej oceny właściwości mechanicznych stali niskostopowej i niskowęglowej o wysokiej wytrzymałości. Precyzyjne określenie tych parametrów pozwala na zwiększenie bezpieczeństwa użytkowania i serwisowania elementów.