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EN
Progressive, high-strength materials have an important position in the transport industry. In this industry, components are subject to high safety and reliability requirements because they often operate under long-term cyclic stress regimes. The paper presents results of fatigue resistance of high-strength materials such DOMEX 700MC, HARDOX 400, HARDOX 450, and INCONEL 718 (UTS from 850 to 1560 MPa) measured at high-frequency cyclic loading (f = 20 kHz, T = 20 ± 5 ° C, push-pull loading, cycle asymmetry parameter of R = -1) in the area from N = 2x106 to N = 2x108 cycles. Fatigue resistance showed a continuous decrease about average value Sa2x108/Sa2x106 = 19.1%.
PL
W artykule opisano wyniki badań doświadczalnych odporności na obciążenia dynamiczne pojemników z polipropylenu w obniżonych temperaturach. Głównym wnioskiem jest to, że przy ujemnych temperaturach badane tworzywo jest znacznie bardziej podatne na uszkodzenia dynamiczne. Należy o tym pamiętać przy transporcie produktów w opakowaniach wykonanych z tego materiału.
EN
In current economic trends, changes in construction using are required. It usually leads to changes in value and type of the working load on building structures, with the requirement to rate the technical state and replace or strengthen the elements. An important aspect of determining the residual bearing capacity of damaged bending reinforced concrete elements is the research concerning the influence of difference defects and damages on the change of strength and deformability. In the article main types of damages and defects, methods of studies of damaged reinforced concrete elements and the expediency of usage of this elements are described. However, most methods are suitable only for certain defects and damages due to the large complexity of calculations and the consideration of multifactoriality. Significant complexity of a single method for calculating damaged elements depends on the possible changing stress strain state of an element in combination with certain defects and damages, the presence of a non-complete separation where during loading or alteration of the damaged element the fractions become included in the work, reinforced concrete is the composite material which carrying complexity in calculating the joint work of its components.
EN
The expressions of the probabilities density distribution of failure loading for an elastic isotropic body under the action of a homogeneous axisymmetric loading are written. The disc-shaped cracks that do not interact with each other are uniformly distributed. The correlation for finding the most probable, mean value, dispersion and variation coefficient of failure loading are obtained. The dependence of the mentioned statistical strength characteristics on the type of applied loading, number of defects (body sizes) and structure material heterogeneity are investigated.
5
Content available Odporność na przebicia materiałów kompozytowych
PL
Konstrukcjom, które przenoszą obciążenia dynamiczne i których odporność decyduje o życiu i bezpieczeństwie człowieka stawia się szczególne wymagania. Wymagania dotyczą zarówno sfery materiałowej jak i konstrukcyjnej. To z kolei zmusza do poszukiwania optymalnych metod obliczeniowych, z uwzględnieniem nieliniowości, tak geometrycznej jak i fizycznej, wynikającej z konfiguracji struktury konstrukcji. Przykładem są różne konstrukcje balistyczne (osłony balistyczne), które są uderzane pociskami w których skumulowana jest ogromna energia. W takim przypadku uderzenie w tarczę (osłonę) pociskiem można rozpatrywać jako obciążenie spowodowane uderzeniem masą. Matematycznie zjawiska obciążeń przy dużych szybkościach odkształceń opisuje się różnymi modelami. Aparat matematyczny jest dość złożony ponieważ wymagana jest duża liczba „współczynników”, ponadto uzyskane wyniki badań nie zawsze są powtarzalne i ma na to wpływ wiele czynników. W pracy zaprezentowano wyniki przestrzeliwania tarcz wielowarstwowych z materiałów kompozytowych pociskami kalibru 7,62 mm. Tarcza składała się z trzech warstw, warstwy zewnętrzne stanowiły okładziny stalowe lub aluminiowe, warstwę wewnętrzną stanowiło drewno naturalne lub modyfikowane. Próbki w kształcie tarcz były o średnicy 50 mm i różnej grubości. Wyniki badań pozwoliły ocenić wpływ modyfikacji drewna na jego odporność na przebicia.
EN
For structures that carry dynamic loads, the requirements are imposed for safety reasons. The requirements apply to both materials and construction. This requires searching for optimal calculation methods, including geometric and physical nonlinearity, which are results from the construction of the structure. An example is various ballistic structures (ballistic shields), which are hit by bullets in which huge energy is accumulated. In this case, the hitting in the shield with a bullet can be considered as a load due to mass impact. Loads at high strain rates are described by various mathematical models. The mathematical model is complex because a large number of "coefficients" is required, moreover, the obtained test results are not always repeatable. The paper presents the results of shooting multilayer plates with composite materials with 7.62 mm caliber bullets. The shield consisted of three layers, the outer layers were steel or aluminum, the inner layer was natural or modified wood. The samples had the shape of a shield and were 50 mm in diameter and of different thickness. The results of the research allowed to assess the impact of wood modification on its puncture resistance.
EN
Extensive efforts have been made to gain a better understanding of the failure behaviour of rocks and rock-like materials, but crack propagation and failure processes under compressive-shear loading have not yet been comprehensively investigated. To address this area of research, the peak shear strengths (τ) and failure processes of specimens with multiple joints are studied by lab testing and particle flow code (PFC2D). Four types of failure modes are observed: (a) shear failure through a plane (Mode-I), (b) intact shear failure (Mode-II), (c) oblique shear crack connection failure (Mode-III), and (d) stepped path failure (Mode-IV). The failure mode gradually transformed to Mode-III as α (joint inclination angle) increases from 0° to 90° in the specimens. In addition, with increasing joint distance (d) in the specimens, the failure mode changes to Mode-II. As the non-overlapping length between joints (c) in the specimens increases, the failure mode changes to Mode-IV. The joint geometry has a major influence on the shear strength of the jointed specimens. The peak shear strength of specimens with different joint inclination angles is obtained when α = 45°. Additionally, the peak shear strength increases as the joint distance (d) and non-overlapping length (c) increase.
EN
The geometry and orientation of cavities in a rock mass has a significant influence on the failure mechanism and fracture propagation. The theoretical study of these behaviors is of great importance to enable fundamental understanding of unstable failure in rock mechanics. A very limited number of experimental studies have been conducted for sandstone specimens containing oval cavities. Sensitive parameters include the short axis (b) to long axis (a) ratio. Here, we enhance the present understanding of crack coalescence behavior around an oval cavity by applying uniaxial compression tests to sandstone cores containing manually inserted single oval cavity, combined with photographic and acoustic emission monitoring. The b:a ratio was varied from 1/4 to 1/1, thus the cross-sectional cavity shape evolved from oval to a fully circular opening. The experimental results showed that the stress–strain curves of specimens containing cavities exhibited multiple stress reductions prior to peak strength, which led to a sudden increase in the accumulated AE count-rate. As the b:a ratio was increased, the uniaxial compressive strength, crack initiation stress and peak strain of cavity specimens all decreased linearly. Tensile fractures, shear fractures, and compound shear-tensile fractures were all observed to emanate from the cavities. Compared to the intact specimen, the failure mode of cavity specimens comprised a mixture of tensile and shear cracks, emanating from the tips (or surfaces) of the oval cavity. For specimen with a cavity angle of 45°, when the b:a ratio was below 1/2, no tensile crack from the surface of short axis was initiated, whereas tensile crack was observed clearly after b:a = 1/2. This study not only increases our understanding of mechanical failure behavior in fractured rock, but also enhances our knowledge of underground tunneling or roadway stability.
EN
The aim of this article is to show that it is possible to create an experimental database to better model Portevin–Le Châtelier (PLC) phenomenon with two kinds of solicitation. Indeed, two kinds of specimen are tested: conventional tensile specimens and specimens designed for plane strain tensile test. In order to better understand this phenomenon and above all to put away any geometry effect, two materials are tested: one without PLC bands (AU4G) that is used as reference and AlMg3 which is well known for its PLC bands. The image correlation tool is used to analyse the creation and the spread of PLC bands. Characteristic parameters of the bands are then measured: width, angle, transported strain, strain rate, and velocity. The originality of this paper is first to show that PLC bands are present during plane strain tensile test and then to characterize the bands thanks to image correlation. These experimental databases could be very useful for those who develop models on PLC phenomenon.
EN
The main aim of the investigations was to determine the significance of parameters of RFSSW for the strength parameters of the resulting joint. RFSSW joints were made in 0.8-mm-thick 7075-T6 aluminium alloy using different welding parameters (tool rotational speed v, tool plunge depth, and joining time). The load capacity of joints was determined by shear tests. The optimum welding parameters which assure the highest load capacity (4.09 kN) in the tensile/shear test are: tool rotational speed of 3000 rpm, tool plunge depth of 1.55 mm, and joining time of 1.25 s. In the conditions of the static tensile test under pure shear the highest joint capacity (6.48 kN) is found for the joint welded at a tool plunge depth of 1.7 mm. Depending on the tool plunge depth, three types of joint damage were observed during tensile/shear tests: plug type fracture, shear fracture, and plug-shearracture. Incomplete refill is the main weld defect observed which is located on the path along which the sleeve plunges into the sheet. It was also found that alclad between the upper and lower sheets worsens the joint quality between the stir zone and thermo-mechanically affected zone.
EN
This paper focuses on the analysis of mechanical properties of organic-inorganic polymeric hybrid material Multimetall “Stahl 1080” containing metallic particles. This material is designed for the regeneration of used metallic parts made of steel, cast iron, or composite materials. This type of material provides a 100% contact with the surface of the filled material, attenuation of vibration loads during the operation under strains, as well as protection against corrosion and tribological wear. The analysis concentrated on the behaviour of the material under vibration loads at higher temperatures.
PL
W artykule zaprezentowano analizę właściwości mechanicznych materiału hybrydowego polimerowego organiczno-nieorganicznego Multimetall “Stahl 1080” zawierającego cząstki metaliczne. Materiał ten został zaprojektowany w celu regeneracji zużytych metalicznych części ze stali, żeliwa lub materiałów kompozytowych. Ten typ materiału zapewnia 100% przyleganie do powierzchni pokrywanego materiału, tłumi drgania, jak również chroni przed korozją i zużyciem tribologicznym. Analizę skoncentrowano na badaniu oddziaływania na materiał drgań w wysokich temperaturach.
EN
This work concerns the numerical analysis of the gantry crane beam in the context of the safety of the structure. The mathematical model and numerical simulations of mechanical phenomena in the gantry crane beam are presented in this paper. The analysed gantry crane beam has a T-section. As a result of the computations carried out, the stresses and displacements of the gantry structure were obtained. The influence of the value and loading force position on the equivalent stress in the gantry crane beam was evaluated. It was sought that the maximum value of Huber-Mises-Hencky stress induced in the beam was less than the strength of material, so the design is safe.
EN
A three dimensional finite element based progressive damage model has been developed for the failure analysis of notched composite laminates. The material constitutive relations and the progressive damage algorithms are implemented into finite element code ABAQUS using user-defined subroutine UMAT. The existing failure criteria for the composite laminates are modified by including the failure criteria for fiber/matrix shear damage and delamination effects. The proposed numerical model is quite efficient and simple compared to other progressive damage models available in the literature. The efficiency of the present constitutive model and the computational scheme is verified by comparing the simulated results with the results available in the literature. A parametric study has been carried out to investigate the effect of change in lamination scheme on the failure behaviour of notched composite laminates.
EN
The article presents designing of gearboxes using Inventor Professional 2017 and the ability to implement these projected models to the Simulation Mechanical 2017. For comparison there were design purposes transmission gears as: spur gear with straight teeth and worm gear. The results of calculations and parameters of the transmission gears are presented in tabular form. Shown dynamic analysis-nonlinear allowing to examine the transmission gears for endurance.
PL
W artykule przedstawiono proces projektowania przekładni przy pomocy programu Inventor Professional 2017 oraz możliwość zaimplementowania tychże modeli do programu Simulation Mechanical 2017. Dla celów porównawczych zaprojektowano przekładnie: walcową (o zębach prostych), a także przekładnię ślimakową. Wyniki obliczeń oraz parametry przekładni przedstawiono w postaci tabelarycznej. Przeprowadzono analizę dynamiczną-nieliniową pozwalającą na zbadanie przekładni pod kątem ich wytrzymałości.
PL
Silnik spalinowy jest obecnie jednym z najpowszechniej stosowanych jednostek napędowych w pojazdach samochodowych. Nieustanny rozwój konstrukcji silników spalinowych wymaga stosowania coraz bardziej wytrzymałych materiałów. Spośród wielu dostępnych metod oddziaływania na właściwości wytrzymałościowe warstwy wierzchniej materiałów stosowanych w budowie silników spalinowych jest implantacja jonowa. W niniejszej pracy przedstawiono przegląd prac związanych z badaniem oddziaływania implantacji jonów różnych pierwiastków na właściwości warstwy wierzchniej materiałów stosowanych w przemyśle motoryzacyjnym. Zwrócono uwagę na wpływ domieszkowania jonów na takie właściwości warstwy wierzchniej jak mikrotwardość, odporność na zużycie tribologiczne, żaroodporność oraz odporność na korozję.
EN
The combustion engine is currently one of the most commonly used propulsion units in vehicles. The continuous development of internal combustion engines requires more and more durable materials. Among the many available methods of influence on the strength properties of the materials surface layer, used in the construction of internal combustion engines are ion implantation. In this paper we present a review of work related to the study of influence of ion implantation of different elements on the surface properties of materials used in the automotive industry. Attention has been paid to the influence of the ionic dopers on the properties of the surface layer such as microhardness, tribological wear resistance, heat resistance and corrosion resistance.
EN
The article presents the advantages of using gear cycloid. They indicated modern methods of their use. The principles of action Cyclo gear having two planetary gears with epicycloid outline. It presents modern materials that can be used in the gear-type cyclo. Carried out simulations using Inventor Professional is aimed to show dynamic analysis takes into account the use of different materials used in the transmission gear input shaft.
PL
W artykule przedstawiono zalety stosowania przekładni cykloidalnych. Wskazano nowoczesne metody ich zastosowania. Omówiono zasady działania przekładni cykloidalnej po-siadającej dwa koła obiegowe o zarysie epicykloidy. Przedstawiono nowoczesne materiały, które można zastosować w przekładniach typu cyclo. Przeprowadzano symulacje z użyciem programu Inventor Professional mającą na celu pokazanie analizy dynamicznej uwzględniającej wykorzystanie różnych materiałów, stosowanych na wale wejściowym przekładni.
16
Content available remote On the material's sensitivity to non-proportionality of fatigue loading
EN
Many researches have shown that fatigue behaviour of a number of materials is significantly different in non-proportional loading conditions when compared to proportional ones. These differences concern stress–strain characteristics, fracture, the phenomena taking place in the material, and finally fatigue life. The aim of this study is to provide a survey on basic experimental results and methods of taking into account a material's sensitivity to non-proportionality of loading in multiaxial fatigue life estimation models for metals.
EN
Aluminium and copper plates are explosively cladded with Al 5052, copper and SS 304 interlayers and the results are reported. While continuous molten layer is obtained in conventional explosive clads, a smooth interface, devoid of defects, is obtained in interlayer laced explosive clads. The mechanical properties of interlayer laced explosive clads confirm higher kinetic energy utilization leading to stronger clad. Ram tensile, shear strengths and Vickers microhardness of Al–Cu explosive clad with different interlayers are higher than conventional two layer clad.
18
EN
Damage occurring at the work of plate structures may grow to a considerable size. The joint action – the detection of a defect at the earliest possible stage, the monitoring of its growth and the determination of its critical size in the context of structural reliability allows optimizing the cost of the maintenance and repair of structural elements. Thus the development of monitoring systems for permanent observation of fault evolution is of great importance among civil, mechanical and aerospace engineering communities. This paper focuses on a diagnostic system dedicated for plate structures with a variable length linear crack using the guided wave-based technique and a novel ellipse-based binary damage imaging algorithm. The emphasis is put on the relationship between the configuration of embedded piezoelectric transducers and the extent of a defect possible to identify. Numerical and experimental results show that the proposed diagnostic system has a great potential for the implementation in monitoring systems dedicated for the evaluation of damage growth.
19
EN
2524-T3 aluminum alloy sheets with different grain sizes (13 μm, 59 μm, 178 μm, 355 μm, 126 μm, and 87 μm) were prepared using methods such as rolling and annealing. The microstructures and mechanical properties of the 2524-T3 aluminum alloy sheets were studied using optical microscopy (OM), scanning electron microscopy (SEM), and tensile and fatigue crack growth (FCG) rate tests. The grain size had a significant effect on the fatigue crack growth (FCG) rate. Alloys with grain sizes between 50 and 100 μm exhibited high fatigue crack propagation resistances and the lowest FCG rates (da/dN = 1.05–1.45 × 10−3 mm/cycle at ΔK = 30 MPa m1/2). Microstructural observations revealed that fatigue cracks propagated more tortuously in the alloy with grain sizes within the range of 50–100 μm. This result is attributed to the combined effects of grain boundaries, crack deflection, fracture surface roughness-induced crack closure, and plasticity-induced crack closure.
EN
Underground network infrastructure shows that even objects functioning in the third technical condition, according to ATV A127, and subjected to rehabilitation with the use of close-fit trenchless technologies are capable of withstanding external loads. It is necessary to conduct analysis and research regarding the mechanical properties of pipelines strengthened with close-fit liners. Calculations, based on laboratory tests, were carried out using the Finite Element Method and Abaqus software as a computational tool. This paper aims to increase knowledge in the area of the possibility of using close-fit liners for pipelines operating in the second technical condition according to ATV A127. A direct and applicable value of the carried out calculations is to provide knowledge about the real bearing capacity of conduits renewed with close-fit liners, and in particular a Trolining liner. The knowledge gained as a result of research, which was conducted in the previous stage, and calculations can be a basis to undertake a discussion on the selection of the strength parameters of close-fit liners.
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