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PL
W pracy przedstawiono budowę nowej postaci konstrukcyjnej metalowego sprzęgła o dużej podatności skrętnej oraz opis stanowiska badawczego i metodykę wyznaczania jego charakterystyk dynamicznych. Zaprezentowano także uzyskane wyniki badań, pozwalające na wyznaczenie wymienionych charakterystyk.
EN
A recently developed construction of a coupling made of metal, high-susceptible to torsion as well as a description of a test stand and a methodology of determination of dynamic characteristics have been presented in the paper. The results achieved in the course of research allowing the above mentioned characteristics to be determined, have been also presented.
2
Content available remote A non-diagonal singularity-free model in torsion gravity
100%
Open Physics
|
2012
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tom 10
|
nr 4
846-849
EN
In the context of torsion (teleparallel) gravity, we focus on discussing the spin effects of Dirac particles associated with the non-diagonal singularity-free model (Mars space-time). We see that the vector part depends on the radial r and z directions and the axial-vector will be along the radial direction, that is, it will be symmetric about radial direction. Furthermore, the t = 0 case of the Mars metric is considered, thence it is seen that the axial-vector vanishes.
3
Content available remote On the geometry of the space-time and motion of the spinning bodies
100%
Open Physics
|
2013
|
tom 11
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nr 3
296-316
EN
In this paper an alternative theory about space-time is given. First some preliminaries about 3-dimensional time and the reasons for its introduction are presented. Alongside the 3-dimensional space (S) the 3-dimensional space of spatial rotations (SR) is considered independently from the 3-dimensional space. Then it is given a model of the universe, based on the Lie groups of real and complex orthogonal 3 × 3 matrices in this 3+3+3-dimensional space. Special attention is dedicated for introduction and study of the space S × SR, which appears to be isomorphic to SO(3,ℝ) × SO(3,ℝ) or S 3 × S 3. The influence of the gravitational acceleration to the spinning bodies is considered. Some important applications of these results about spinning bodies are given, which naturally lead to violation of Newton’s third law in its classical formulation. The precession of the spinning axis is also considered.
Open Physics
|
2010
|
tom 8
|
nr 3
304-311
EN
Analytical derivation of electronic band gap of Single Walled Carbon Nanotube (SWCNT) under a small percent of uniaxial and torsional strains is in this paper. Our approach is based on a kind of π-Tight Binding (π-TB) approximation which includes interactions of the second and the third neighbors of each carbon atom in addition to the nearest ones. Implementing the approach of this paper, yields more precise results than those of other researches.
5
Content available remote Phase space analysis of interacting dark energy in f(T) cosmology
88%
EN
In this paper, we examine the interacting dark energy model in f(T) cosmology. We assume dark energy as a perfect fluid and choose a specific cosmologically viable form f(T) = β√T. We show that there is one attractor solution to the dynamical equation of f(T) Friedmann equations. Further we investigate the stability in phase space for a general f(T) model with two interacting fluids. By studying the local stability near the critical points, we show that the critical points lie on the sheet u* = (c − 1)v* in the phase space, spanned by coordinates (u, v, Ω, T). From this critical sheet, we conclude that the coupling between the dark energy and matter c ∈ (−2, 0).
6
Content available remote Effects of hydrogen induced elastic and plastic straining on its transport in Al
88%
EN
Hydrogen entering at cathodic polarization produces the straining of Al. In the course of increased polarization, the elastic strain causing the up-hill diffusion of hydrogen present in metal and then the plastic deformation creating of hydrogen traps have been introduced. As a result, the unusual appearance of hydrogen permeation transients and the retardation of hydrogen transport and its accumulation within the plastically deformed metal occur at the low and at the high polarization, respectively. The supersaturation of surface layers with hydrogen or the formation of the patchy hydride like layer have been discussed to be the source of the observed metal straining.
7
Content available remote On the optimal design of viscoplastic bars under combined torsion with bending
88%
EN
The governing equation for viscoplastic simultaneous torsion and bending of a prismatic bar is derived. Then a certain particular closed-form solution of this equation is found; it corresponds to an elliptic cross-section with the ratio of semi-axes depending on the bending-to-torsion ratio. This solution proves to be optimal if the optimization constraint is imposed on initiation (nucleation) and growth of material damage and if the material properties conform to the Huber-Mises-Hencky failure hypothesis.
EN
Intra-abdominal neoplasmatic testicular torsion is a very rare clinical condition, which is normally not considered during differential diagnosis of acute appendicitis. The above-mentioned is most often observed in patients after puberty, without any previous specific symptoms apart from the absence of the testis in the scrotum and inguinal canal or periodic pain in the right lower abdomen. The study presented a case of a 22-year old male patient who was admitted and operated with suspicion of acute appendicitis. During surgery we observed intra-abdominal testicular torsion, both the testis and appendix were excised. Postoperative histopathological results were as follows: seminoma of the testis and normal appendix. The study presented available data concerning the above-mentioned rare clinical condition, as well as principles of diagnosis and treatment.
|
|
tom Vol. 32, nr 2
98-106
PL
W pracy dokonano przeglądu kryteriów wieloosiowego zmęczenia, które uwzględniają wartość stosunku naprężeń normalnych i stycznych. Przedstawiono również charakterystyki zmęczeniowe na zginanie i skręcanie dla wybranych materiałów konstrukcyjnych. Wyznaczono stosunek naprężeń normalnych do stycznych dla ustalonej liczby cykli Nf w przedziale 5?105÷2?106. Ponadto przeprowadzając analizę równań zmęczeniowych oraz różnicy względnej R podzielono materiały na grupy, dla których można lub nie można stosować stałą wartość rozpatrywanego stosunku w kryteriach zmęczenia, które ten stosunek uwzględniają. W przypadku równoległości charakterystyk stosunek naprężeń normalnych do stycznych wyróżnia się stałością i przyjęto, że różnica względna R nie przekracza 10%. Do materiałów charakteryzujących się takimi właściwościami należą stopu aluminium, większość stali węglowych, niektóre stale stopowe i część żeliw. W przypadku braku równoległości nie można zastosować stałości wartości stosunku naprężeń normalnych do stycznych w kryteriach zmęczeniowych. Takimi właściwościami najbardziej wyróżnia się między innymi mosiądz CuZn40Pb2, stal średniostopowa 42 CrMo4V oraz stal wysokostopowa 35NCD16.
EN
The paper presents a review of the multiaxial fatigue criteria including a ratio of normal and shear stresses. The paper also contains fatigue characteristics for bending and torsion of some selected constructional materials. The ratio of normal stresses to shear stresses was determined for the defined number of cycles Nf in the range 5?105÷2?106. Moreover, from the performed analysis of fatigue equations and the relative difference R it appears that materials can be divided into groups for which it is possible or it is not possible to apply the constant value of the considered ratio in the criteria including this ratio. In the case of parallelism of the characteristics, the ratio of normal stresses to shear stresses is constant and it is assumed that the relative difference R does not exceed 10%. Aluminium alloys, most of carbon steels, some alloy steels and some cast irons are the materials with such properties. If there is no parallelism, a constant value of the ratio of normal and shear stresses cannot be applied in fatigue criteria. The group of materials characterized by such properties includes, among others, brass CuZn40Pb2, medium-alloy steel 42 CrMo4V and high-alloy steel 35NCD16.
10
75%
PL
Celem pracy było zbadanie wpływu różnych parametrów odkształcenia na rozdrobnienie ziarna w próbie skręcania pod hydrostatycznym ciśnieniem próbek pierścieniowych wykonanych ze stopu AlMg2. W pracy zbadano strukturę odkształconych próbek oraz wyznaczono wielkość ziarna i twardość materialu. W ramach pracy wyznaczono własności mechaniczne nanostopu AlMg2.
EN
The purpose of this paper was to determine the effect of various torsion parameters on grain size reduction during a test of twisting ring samples from AlMg2 alloy under hydrostatic pressure. In this paper, the structure of deformed samples was irwestigated and grain size and material hardness were determined. As a part of the paper, mechanical properties of AlMg2 nanoalloy were determined.
PL
W pracy przedstawiono wyniki badań wpływu metalowego sprzęgła podatnego skrętnie na impulsowe obciążenie układu napędowego maszyny roboczej. Badania przeprowadzono na stanowisku badawczym, stanowiącym doświadczalny układ napędowy z zamontowanym badanym sprzęgłem podatnym.
EN
The results of research on impact of a torsion susceptible coupling made of metal on impulse load of a drive system of a machine have been presented in the paper. The tests have been carried out at a test stand containing an experimental drive system including a mounted coupling to be tested.
EN
The paper presents experimental results of investigations carried out under complex stress state on the 2024 aluminium alloy (used by aircraft industry) and P91 steel (used at power plants). Second-order effects associated with cyclic loadings enforced by the trapezoidal signals in the two mutually perpendicular directions are identified. It is shown, how the cyclic loading and its parameters (strain amplitude and frequency) influence the simultaneous monotonic loading in the direction perpendicular with respect to the cyclic one. Moreover, the paper presents an analysis of the selected mechanical properties variations on the basis of an initial yield locus evolution.
13
Content available remote Torsional deformation and rotary driving characteristics of SMA thin strip
75%
EN
The torsional deformation properties of a TiNi shape-memory alloy thin strip were investigated. The results obtained are summarized as follows. (1) The martensitic transformation starts at the edge of the thin strip. (2) The torsional deformation properties change slightly under thermomechanical cycling. (3) The fatigue life in pulsating torsion is longer than that in alternating torsion. (4) A simple rotary driving element can be developed by using the SMA thin strip.
PL
Przedstawiono wyniki badań plastyczności aluminium gatunku AO, otrzymane podczas dwukierunkowego cyklicznego skręcania próbek tego materiału względem procentowych (20-75%) wielkości odkształcania granicznego jednokierunkowego. Wyniki badań dotyczą temperatur odpowiadających obróbce plastycznej na zimno, ciepło i gorąco. Porównano warunki próby skręcania do warunków walcowania i kucia.
EN
Results of investigations into ductility of aluminium under bidirectional cyclic torsion in the of witch different degrees of strain constituting 20-75 % of the unidirectional torsion limit strain - were applied at the particular stages. The results refer to cold, haft - hot and deformation. Conditions rolling and forging where compared to torsion test conditions.
PL
Przedstawiono porównanie wyników prób ściskania i skręcania na gorąco stali OH18N9 zrealizowanych na nowoczesnych urządzeniach badawczych. Wykazano wpływ sposobu i warunków odkształcania na uzyskane zależności naprężenia uplastyczniającego od odkształcenia. Przeanalizowano możliwość dotrzymania zadanej temperatury i prędkości odkształcenia. Wykazano występowanie nierównomierności odkształcenia w próbach ściskania za pomocą obliczenia wskaźnika beczkowatości oraz badania rozkładu struktury i mikrotwardości.
EN
The results of hot torsion and hot compression tests of austenitic Cr-Ni steel realised on four modern testing machines have been compared in the paper. An influence of the method and conditions of deformation on the flow stress values has been shown. Possibility of keeping temperature and strain rate at a constant level has been analysed. Occurrence of non-uniformity of strain in the compressed specimens has been presented.
16
Content available remote On the torsion of linear higher order connections
75%
Open Mathematics
|
2003
|
tom 1
|
nr 3
360-366
EN
For a linear r-th order connection on the tangent bundle we characterize geometrically its integrability in the sense of the theory of higher order G-structures. Our main tool is a bijection between these connections and the principal connections on the r-th order frame bundle and the comparison of the torsions under both approaches.
PL
Przedstawiono badania doświadczalne dotyczące strunożelbetowych belek drążonych pod działaniem "czystego skręcania" oraz belek żelbetowych o kątownikowym i prostokątnym przekroju poprzecznym obciążonych skręcaniem, zginaniem i ścinaniem.
EN
The paper presents experimental studies, which were carried out in the research laboratory of the Institute of Civil Engineering Wroclaw University of Technology. Research related to reinforced concrete elements subjected to torsion. Presents the results of research carried out by prof. Kaminski. Research J. Kupski - for partially prestressed hollow beams under "pure torsion" and W. Pawlak - the reinforced concrete beams with flanged and rectangular cross-section - loaded torsion, bending and shear.
|
2011
|
tom z. 99
114-116
PL
Celem pracy jest porównanie rozkładów naprężeń w próbkach o przekroju okrągłym i prostokątnym poddanych proporcjonalnemu i nieproporcjonalnemu zginaniu ze skręcaniem. Rozkłady naprężeń w próbkach obliczano numerycznie przy użyciu pro- gramu Matlab [1].
EN
The aim of this paper is comparison of stress distributions in the specimens with circular and rectangular cross-sections, subjected to a proportional and nonproportional bending with torsion. Stress distributions in the specimens were calculated numerically using Matlab. The calculations were performed for three combinations of stresses and two phase shifts.
|
2011
|
tom z. 98
59-60
EN
The aim of the paper is to check if the equivalent stress calculated on the basis of the Huber-Mises-Hencky hypothesis under the complex loading (bending with torsion) for the welded joints could be the base for assessment of their fatigue life. The thesis was verified with the test results obtained for flange-tube and tube- tube welded joints.
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