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1
Content available remote Joinability of centrifugal composite castings
EN
Centrifugal composite castings based on aluminium alloys belong to a group of materials with high potential for application in the automotive and aerospace industries. Their use is limited by the lack of a technology enabling the obtainment of a permanent joint ensuring safe operation. The article presents the results of preliminary surfacing and welding tests of a hybrid centrifugal composite casting based on the AlSi12 alloy and reinforced with silicon carbide (5% by weight) and glassy carbon (5% by weight) particles. Structural tests and the quantitative evaluation of the distribution of structural constituents indicated the possibility of the joining of such composites using the TIG welding process. It was found that overlay welds made using the filler metal having a chemical composition similar to that of the matrix could be treated as a buffer layer. The aforesaid approach should enable the joining of composite castings. The structure of the weld revealed the presence of heterogeneously distributed reinforcing phases, which was related to the gradient structure of centrifugal composite castings. The presence of the Al4C3 phase at the interface between the glassy carbon and the matrix could result in the reduction of corrosion resistance in a humid environment. The structural tests discussed in the article should be supplemented with the assessment of the mechanical properties of the joint. As a result, it will be possible to implement the technology for the welding of composite castings on an industrial scale.
PL
Kompozyty metalowe na osnowie stopów aluminium odlewane odśrodkowo należą do grupy materiałów o dużym potencjale zastosowania w przemyśle motoryzacyjnym i lotniczym. Ograniczeniem ich wykorzystania jest brak technologii łączenia trwałego zapewniającego bezpieczną eksploatację. W artykule przedstawiono wyniki wstępnych prób napawania i spawania kompozytu o osnowie stopu AlSi12 umacnianego cząstkami węglika krzemu (5% wag.) oraz węgla szklistego (5% wag.) odlewanego odśrodkowo. Przeprowadzone badania strukturalne oraz ilościowa ocena rozmieszczenia składników strukturalnych wskazała na możliwość łączenia tego typu kompozytów za pomocą spawania metodą TIG. Stwierdzono, że napoiny wykonane materiałem dodatkowym o zbliżonym do osnowy składzie chemicznym można traktować jako warstwę buforową, co pozwoli na łączenie odlewów kompozytowych. W strukturze spoiny ujawniono niejednorodnie rozmieszczone fazy umacniające. Jest to związane z gradientową strukturą kompozytów odlewanych odśrodkowo. Obecność fazy Al4C3 na granicy węgla szklistego i osnowy może skutkować obniżeniem odporności korozyjnej w środowisku wilgoci. Przeprowadzone badania strukturalne należy uzupełnić o ocenę właściwości mechanicznych złącza. Pozwoli to na wdrożenie technologii spawania odlewów kompozytowych do praktyki przemysłowej.
2
EN
The article presents applications of high-strength quenched steels in various industrial sectors and the chronological development of various grades of the aforesaid steels. The research-related tests involved flat butt joints made in 7 mm thick steel grade S1300QL, welded using the following methods: TIG, A-TIG, MAG involving the use of a hard flux-cored surfacing wire, MAG method involving the use of a solid wire, T.I.M.E. method involving the use of a solid wire, laser welding method without the use of the filler metal, hybrid (HLAW) method involving the use of a metallic flux-cored wire, electron beam welding without using the filler metal. The research also involved the performance of the mechanical properties of the welded joints made in quenched steel S1300QL using various welding methods. The joints made using the laser welding method, hybrid welding method and the electron beam welding method were characterised by tensile strength higher than the minimum yield point of steel S1300QL, amounting to 1300 MPa. In turn, the tensile strength of the joints made in steel S1300QL using arc welding methods was lower than the minimum yield point of the steel. All of the test joints were subjected to non-destructive digital radiographic tests. The tests concerning the mechanical properties of the joints with respect to various welding methods were subjected to comparative analysis. The research work finished with the formulation of concluding remarks concerning the mechanical properties of the joints.
PL
Przedstawiono zastosowanie stali ulepszanych cieplnie o wysokiej wytrzymałości w różnych dziedzinach przemysłu oraz chronologiczny rozwój różnych gatunków tych stali. Przedmiotem badań były złącza doczołowe płaskie stali ulepszonej cieplnie w gatunku S1300QL o grubości 7 mm, spawane metodami TIG, A-TIG, MAG z użyciem drutu proszkowego, MAG z użyciem drutu litego, T.I.M.E. z użyciem drutu litego, laserową bez materiału dodatkowego, hybrydową HLAW z użyciem drutu elektrodowego proszkowego z rdzeniem metalicznym i wiązką elektronów bez użycia materiału dodatkowego. Wykonano badania właściwości wytrzymałościowych złączy stali ulepszonej cieplnie typu S1300QL wykonanych różnymi metodami spawania. Złącza spawane metodą laserową, metodą hybrydową oraz wiązką elektronów uzyskały wytrzymałość na rozciąganie wyższą od minimalnej granicy plastyczności stali S1300QL, tj. 1300 MPa. Z kolei złącza stali S1300QL spawane metodami łukowymi nie osiągnęły wytrzymałości na rozciąganie dorównującej minimalnej granicy plastyczności tej stali. Wszystkie badane złącza spawane poddano badaniom nieniszczącym radiograficznym, przy zastosowaniu radiografii cyfrowej. Przeprowadzono analizę porównawczą uzyskanych wyników właściwości wytrzymałościowych złączy w aspekcie różnych metod spawania. Na zakończenie sformułowano wnioski z badań właściwości mechanicznych złączy spawanych.
EN
It is clear that the advantages of fibre glass-reinforced plastics surpass those of steel, but the failure analysis of composite structures is much more complex than that of isotropic materials as composite materials may fail in a variety of ways. In order to simulate the damage and fracture of bolted joints of fibre reinforced composite, the bond-based peridynamic method suitable for elastic, brittle and anisotropic characteristics of composite material is used. The peridynamic model for composite laminate is validated by the finite element method. Then a peridynamic program of composite damage is applied to calculating the damage of bolted joint structure and the damage propagation process and failure mode of the structure is obtained.
EN
The article presents the research results on the mechanical properties of aluminum alloy AW-5083 and its joints welded by hybrid method – traditional MIG and FSW. AW-5083 alloy is the most currently used in shipbuilding industry. Friction Stir Welding (FSW) – a new technology can be successfully used for butt-welding of different types of aluminum alloy sheets. FSW method can be an alternative to traditional arc welding methods i.e. MIG or TIG. Hybrid welding (FSW with MIG or TIG) could be used in cases when joining only by FSW is not possible. Welding parameters used for the connection of the sheets were presented. Metallographic analysis showed the correct construction of structural bonded joints. The research was carried out using a static tensile test in accordance with the requirements of the Standard PN-EN ISO 4136:2013-05. Flat samples cut perpendicular to the direction of rolling were used. The research was conducted at the temperature of +20ºC. The test shows that the mechanical properties of joints made by hybrid method compered to native material were lower. The tensile strength of joint was lower by 20% then native material 5083 while its yield stress was lower only about 6%. The biggest change was observed in case of plastic properties. Elongation of joint was over 50% lower compared to native material. Despite the decrease of mechanical properties, they meets the requirements of classification societies, so the conclusion is that hybrid method (FSW and MIG) of joining AW-5083 can be applied in shipbuilding industry.
EN
This paper presents the results of an examination of cast-on-strap joints of lead acid batteries with different discharge capacities. The galvanic joints of lugs of selected cells in lead acid batteries were analyzed. The study showed some defects that may occur in these joints. Examples of the defects that can affect battery lifespan were presented.
6
Content available remote Strength of the SPR joints - selected aspects
EN
Riveting is one of the oldest joining techniques known to man. Historical sources confirm that as early as at the beginnings of the Bronze Age, solid rivets were used to rivet metal. Over the years, in connection with growing knowledge in the field of welding technology and the availability of weldable steels and other structural metals, riveting has gradually been replaced by cheaper welding techniques. Due to a certain number of features, they have become the main joining techniques in the industry.
EN
An indentation can be formed when inserting a punch along wood fibers at the ends of blanks. The aim of this research is to study structural changes during local compression of wood in longitudinal pressing. Punches of prismatic shape were inserted into samples of Scots pine wood with different moisture content. The stages of wood deformation during the process were analyzed. The author then evaluated changes in the macrostructure of the wood and determined the conditions for obtaining a good-quality indentation. This led to a regression model enabling prediction of the depth of the densified zone. Its size is no more than 105% of the depth of penetration. Images of the densified zone were obtained using a scanning electron microscope, and changes in its microstructure were evaluated. The process of forming a “core” causes uncritical structural changes in the boundary undeformed sections. This underlines the possibility of using local pressing technology along the fibers as an alternative to traditional milling or drilling in order to form grooves and blind holes, for example for such joints as tongue and groove or mortise and tenon.
EN
A geological structural study has been conducted along the tectonic contact zone of the Central Carpathian Paleogene Basin (CCPB) and Pieniny Klippen Belt (PKB) in the eastern Podhale and western Spišska Magura areas. It concerned mostly the Central Carpathian Paleogene flysch strata and, to a lesser degree, the Upper Cretaceous rocks of the PKB. Tectonic deformation structures genetically related to the important tectonic boundary in question occur within a c. 1.5–2 km-wide strip of the Paleogene flysch rocks adjacent from the south to the PKB. Two parallel structural domains have been distinguished within this strip: the contact zone proper in the north and the peri-Pieniny monocline in the south. Most of the minor faults documented in the Paleogene flysch bear a record of dextral motion parallel to the contact zone. Some dextral-reverse oblique slip faults of NE-SW and W-E trends have also been recognized. Discrepancies in the orientation and sense of movement on strike-slip faults in the Paleogene flysch rocks and those in marlstones of the “klippen envelope” of the PKB were encountered. They probably reflect differences in the structural history of both the adjacent rock complexes, as the Upper Cretaceous deposits of the PKB must have experienced more deformation events and, in general, were affected by much more intense strain than those of the CCPB. Contractional structures, such as south-vergent reverse faults and recumbent folds which point to ca N-S tectonic shortening, have also been found in the Paleogene rocks. The entirety of the structural features found in the CCPB is characteristic of a transpressional regime. The regionally consistent coexistence of structures resulting from strike-slip movements and tectonic shortening, as well as features pointing directly to a transpressional regime, prove the transpressional dextral nature of the contact between the CCPB and PKB.
PL
W artykule przedstawiono zasady wykonywania i wypełniania szczelin w nawierzchniach betonowych. Rola właściwego rozmieszczenia szczelin, ich wymiary oraz wypełnienie szczelin stanowią bardzo istotne czynniki, mające wpływ na trwałość nawierzchni betonowych. Precyzyjne zapisy jakie zawierają nowe wytyczne niemieckie ZTV Fug-StBz 2015 r. można uznać za podstawy odpowiedniego podejścia nadzoru oraz samej firmy wykonującej roboty do zasadniczych elementów związanych z trwałym i skutecznym wypełnieniem szczelin.
EN
Principles of making and filling of joints in cement concrete pavements are presented in the paper. Role of proper arrangement of joints, their dimension and filling are very significant factors having influence on durability of concrete pavement. Precise formulations in new German guidelines ZTV Fug-StBz 2015 may help Contractors and Engineers in their work to receive good an durable joints.
10
Content available remote Self-forming screws in the automotive industry
EN
What challenges do we face by using the self-forming screws in the serial production of the modern EPS steering systems?
EN
The paper concerns aluminum joints made using friction stir welding. Although in the aerospace industry there is a tendency to replace metal components with composites, aluminum continues to be a valuable material. Its share in the aircraft structures is the biggest among all structural metals. Lots of aluminum components are made of sheets and most of them require joining. Friction stir welding is a relatively new joining technology, particularly with regard to the sheets having a thickness of 1 mm or lower. The paper is dedicated to non-destructive testing of such joints using ultrasonic inspection. It was found that ultrasonic testing allows for distinguishing between joints without material discontinuities, joint with material discontinuities at the advancing side and joint with discontinuities extending through the whole width of the stir zone. During research only horizontally aligned defects were taken into account.
EN
One crucial characteristic of the aircraft structure are fatigue properties and rivets are usually critical areas in metal airframes due to fatigue cracks nucleation. According to literature, the NACA riveting method offers a huge increase in fatigue life of riveted lap joints. This paper presents FE simulations of quasi-static riveting on a press for standard countersunk rivets and the NACA riveting in two configurations: with a normal brazier rivet and a brazier rivet with a compensator. The analyzed configurations have been compared based on the stress courses on the sheets faying surfaces after riveting process. Due to a lack of data, the rivet length and the squeezing force value were assumed for NACA riveting based on FE simulations. The results indicated beneficial influence of the NACA riveting in the outer sheet (with a countersunk) and disadvantageous influence in the inner sheet. This effect was stronger in the case of the rivet with a compensator.
PL
Podczas pracy maszyny elementy jej mechanizmów połączone są w pary kinematyczne. Miejsca połączeń, którymi są najczęściej przeguby lub ślizgi, są poddawane ogromnym obciążeniom. W celu poprawy ich współpracy stosuje się operację smarowania współpracujących powierzchni, które w trakcie pracy wzajemnie się obracają oraz przemieszczają.
14
Content available Preliminary studies of riveted joints at feed force
EN
The aim of the study was to determine the feasibility of riveted joints in composites materials. Static tensile test method was used. In the test one type of glass fabric was used (Interglas 92140) from which two types of composite samples were prepared. In each sample the same type of fiber with the same fiber orientation – 3 layers - was used. The samples had dimensions of 100×100 mm and thickness of approximately 1 mm. The composite probes were located in a metal frame with a screw connection which was made of screws with nominal thread pitch M5. Screws were tightened with constant torque. It was to provide an axial force to the sample during the tensile test. The frame was placed between cross-bars of tensile machine INSTRON 8516. The samples were stretched at a speed of 0.05 mm/s at a distance up to 15 mm. During the tensile test displacement of the samples and pull force were registered. Depending on the fibre orientations and the value of feed force, damage models were described. On the basis of the results the possibility of usage of aluminium rivet nuts connections in composite materials was determined.
EN
The article presents the research results on the mechanical properties of aluminum alloy 7020 and its friction stir welded (FSW) joints. For comparison alloy 5083 – the most currently used in shipbuilding alloy was chosen as well as 5059 - the new high-strength alloy. Besides the native material alloys there were investigated their joints welded by FSW - the same method as alloy 7020. Welding parameters used for the connection of the sheets made of 7020, 5083 and 5059 alloys were presented. Metallographic analysis showed the correct construction of structural bonded joints. Friction Stir Welding (FSW) – a new technology can be successfully used for butt welding of different types of aluminum alloy sheets. FSW method can be an alternative to traditional arc welding methods i.e. MIG or TIG. The research was carried out using a static tensile test in accordance with the requirements of the Polish Standards PNEN ISO 4136:2011 and PN-EN ISO 6892-1:2010. Flat samples cut perpendicular to the direction of rolling were used. The research was conducted at the temperature of + 20ºC. The 7020 alloy has higher strength properties then alloys: 5083 and 5059. The yield stress is higher by 14.8% compared to 5083 alloy, and by 11.7% compared to the alloy 5059. Plastic properties of an alloy 7020 are the lowest, but with reserves meet the requirements of classification societies. The joints welded by FSW of 7020 alloy have higher strength properties then joints of alloys: 5083 and 5059. The yield stress achieves the highest value for alloy 7020 and is 24.2% higher than for 5083 alloy and 11.5% for the 5059 alloy. Despite the strength properties also plastic properties are best for 7020 alloy joints.
EN
The article presents the research results on the mechanical properties of aluminum alloy 7020 and its FSW and MIG welded joints. Welding parameters used for the connection of the sheets made of 7020 alloy were presented. Metallographic analysis showed the correct construction of structural bonded joints. Friction Stir Welding (FSW) – a new technology can be successfully used for butt welding of different types of aluminum alloy sheets. FSW method can be an alternative to traditional arc welding methods, especially MIG, which is the most common method of joining aluminum alloys used in shipbuilding. The research was carried out using a static tensile test in accordance with the requirements of the Polish Standards PN-EN ISO 4136:2011 and PN-EN ISO 6892-1:2010. Flat samples cut perpendicular to the direction of rolling were used. The research was conducted at the temperature of + 20ºC. Friction stir welded joints of 7020 alloy have higher strength properties compared to MIG welded joints. The yield stress of FSW joint is higher by 14.2% compared to MIG welded joint, and at the same level as the native material. Plastic properties of FSW joint are much higher than MIG joint (over 40%). Confirmation of high strength properties of FSW joint is the place of crack - beyond the weld in the native material.
17
Content available remote Research advancing the design of large span deep corrugated metal culverts
EN
While it has long been understood that culvert response to live load depends on three dimensional effects, and that design of these heavily redundant structures should account for ultimate strength, it has only recently been possible to measure and calculate this behaviour. Laboratory tests on a deep corrugated metal box culvert of 10m span are described, including tests before burial and one test of the shallow buried structure up to the ultimate strength limit. Three dimensional finite element analysis is then discussed. The ultimate strength test demonstrates the substantial reserve capacity due to three dimensional load spreading. Finally, the potential for undertaking design using parametric studies based on three dimensional finite element analyses is illustrated.
PL
Mimo tego, że od dawna rozumiemy, że reakcja przepustów na obciążenia zmienne zależy od sił działających w trzech wymiarach, a podczas projektowania tych wysoce redundantnych konstrukcji należy brać pod uwagę ich wytrzymałość graniczną, dopiero niedawno pojawiła się możliwość mierzenia i obliczania takiego zachowania. W tej pracy opisano testy laboratoryjne przepustu skrzynkowego ze stalowej blachy falistej o głębokiej fali o rozpiętości 10 m, w tym testy przed zasypaniem oraz jeden test konstrukcji z płytkim naziomem aż do granicy wytrzymałości. Następnie omówiona jest trójwymiarowa analiza elementów skończonych. Test wytrzymałości granicznej pokazuje znaczącą rezerwę wytrzymałości dzięki rozprzestrzenianiu się obciążeń w trzech wymiarach. Na koniec przedstawiono potencjał projektowania przy użyciu badań parametrycznych opartych o trójwymiarowe analizy elementów skończonych.
18
EN
Axial forces F in the lap joints connections are responsible for mutual displacements δ of connected walls (F=Kδ×δ), and bending moments M—their mutual rotations about angle φ (M=Sj×φ). Basing on formulae provided in EC3 concerning the coefficients of stiffness of the basic joint components, analogical formulae have been derived for sliding lap joints (Kδ) and rotary lap joints (Sj). Results achieved from stiffness formulae for various types of lap joints are compared with the experimental results of known models presented in literature. Our experimental results of single-cut joints made of blind-bolts of the type BOM R16 for cold-formed sections are also presented. Elements with those connections are simultaneously tested for bending and shear. Experimental investigations ended with the paths of static equilibrium (PSE) illustrated by M–φ diagrams and compared with three-segmental broken curves achieved from formulae proposal mentioned above. It can be stated the lap joints stiffness described by the three-segmental broken curves are accurate for the real behavior of discussed connections. Results of each experimental investigations are characterized with higher and lower dispersion. The broken curves situated under the paths of static equilibrium (PSE) are safe and reflect in satisfying way the behavior of bar structures with investigated joints.
PL
W artykule przedstawiono zagadnienie wytrzymałości okrłgłych połączeń przetłoczeniowych wykonanych dla cienkiej blachy stalowej z materiału 1.0338 (DC04). Dla blach poniżej 1 mm niezwykle istotne jest zachowanie wysokiej sztywności narzędzi oraz czystości powierzchni łączonych elementów. Podczas badań eksperymentalnych analizowano wytrzymałość na ścinanie oraz zachowanie się przetłoczenia podczas testu rozdzielenia. Na podstawie otrzymanych wyników stwierdzono pewną niejednorodność w wartościach maksymalnej siły niszczącej złącze.
EN
This paper presents the strength issue for round clinching joints made of 1.0338 (DC04) thin steel sheet. For sheets of thickness below 1 mm it is important to maintain high toolrigidity and cleanliness of joined element surfaces. Their shearing strength and redrawingjoint behavior during separation test was analyzed during experimental researches. Basedon achieved results, some heterogeneity in maximum joint breaking force was observed.
20
Content available remote Thermal drilling as a progressive technology of creating of bushings
EN
The contribution deals with joining of materials and creating of bushings from aluminium materials, with using of new joining technology by thermal drilling, it means by Flowdrill method. This method is using at joining of materials such as sheets, pipes, hollow profile, where the thickness of material does not allow to make the drilling with enough number of threads. Also we can compare this thermal drilling technology with production of smooth cylindrical and conical bushings by forming technologies as hole burnishing. This paper was made with cooperation with firm Commerc Service spol.s.r.o., Presov.
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