Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "rigidity" wg kryterium: Temat

  Lista filtrów
Wyrównaj
Wyświetlanie 1-15 z 41
Tytuł:
Rigidity of monodromies for Appells hypergeometric functions
Autorzy:
Haraoka, Y.
Kikukawa, T.
Powiązania:
https://bibliotekanauki.pl/articles/254789.pdf
Data publikacji:
2015
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
rigidity
monodromy
arrangement of hyperplanes
Opis:
For monodromy representations of holonomic systems, the rigidity can be defined. We examine the rigidity of the monodromy representations for Appell's hypergeonietric functions, and get the representations explicitly. The results show how the topology of the singular locus and the spectral types of the local monodromies work for the study of the rigidity.
Źródło:
Opuscula Mathematica; 2015, 35, 5; 567-594
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of Characteristics of Turning of Shafts with Low Rigidity
Autorzy:
Świć, A.
Gola, A.
Hajduk, M.
Powiązania:
https://bibliotekanauki.pl/articles/118069.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Promocji Wiedzy
Tematy:
turning
shaft with low rigidity
modelling
Opis:
Numerical studies were conducted with the use of a computer program permitting the determination of the basic dynamic characteristics of the process of machining and the presentation of graphic characteristics of the numerical simulations performed. Analysis was performed of the relation of the output parameters of the dynamic system to the input parameters, relative stiffness coefficient B to feed rate and depth of machining, change of retardation and time constants to rotary speed and depth of machining, and of the frequency and time characteristics of models of the dynamic system of machining of shafts with low rigidity.
Źródło:
Applied Computer Science; 2016, 12, 3; 61-73
1895-3735
Pojawia się w:
Applied Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Closed-form solutions for torsion analysis of structural beams considering web-flange junctions fillets
Rozwiązania w postaci zamkniętej problemu skręcania belek konstrukcyjnych z uwzględnieniem promieni przejściowych pomiędzy łączonymi segmentami
Autorzy:
Shahpari, S-Z.
Hematiyan, M. R.
Powiązania:
https://bibliotekanauki.pl/articles/282035.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
torsion
shearing stress
torsional rigidity
fillet
Opis:
In this paper, an effective semi-analytical method is presented for torsion analysis of structural beams with various kinds of junctions such as T, I, H, E and + beams. A fairly Simple but precise formulation based on analytical and accurate numerical solutions is presented for evaluating the shearing stress at critical points and computing the torsional rigidity of a member under torsion. The problem is formulated based on Prandtl’s stress function. The cross-section is decomposed into several segments, including straight, curved, end, and junction segments. The torsion problem is solved in each segment separately. Standard junction segments are analyzed using the finite element method with a fine mesh. Other segments are analyzed by analytical methods. Closed-form expressions in terms of geometrical parameters are found for the shearing stresses at critical points of each segment. The torsional rigidity of the cross section is also expressed by a closed-form expression. The presented formulations can be used for analysis of a wide range of thin- to moderately thick-walled complicated sections.
W pracy przedstawiono efektywne, półanalityczne rozwiązanie problemu skręcania belek konstrukcyjnych o rożnych przekrojach, takich jak T, I, H, E oraz +. Całkiem proste, a jednocześnie dokładne sformułowanie zagadnienia oparte na rozwiązaniach analitycznych i numerycznych zaprezentowano dla przypadku obliczania naprężeń ścinających w krytycznych punktach przekroju oraz wyznaczania sztywności torsyjnej elementu poddanego obciążeniu skręcającemu. Rozwiązanie zadania oparto na funkcji naprężeń Prandtla. Przekrój poprzeczny belek zdekomponowano na kilka segmentów, włączając w to elementy prostoliniowe i zakrzywione, końcowe oraz łączące. Problem skręcania rozwiązano dla każdego segmentu oddzielnie. Typowe elementy łączące przeanalizowano za pomocą metody elementów skończonych z zastosowaniem drobnej siatki. Pozostałe segmenty obliczono analitycznie. Rozwiązanie w postaci zamkniętej względem parametrów geometrycznych wyznaczono pod kątem naprężeń ścinających w krytycznych punktach każdego segmentu. Sztywność skrętną całego przekroju wyrażono również formułą w postaci zamkniętej. Zaprezentowane rozwiązania mogą być stosowane w analizie skręcania szerokiego typoszeregu od cienko- po umiarkowanie grubościennych belek konstrukcyjnych o skomplikowanym kształcie przekroju poprzecznego.
Źródło:
Journal of Theoretical and Applied Mechanics; 2013, 51, 2; 393-407
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Method of achieving accuracy of thermo-mechanical treatment of low-rigidity shafts
Autorzy:
Świć, A.
Draczew, A.
Gola, A.
Powiązania:
https://bibliotekanauki.pl/articles/102605.pdf
Data publikacji:
2016
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
low-rigidity shafts
thermomechanical treatment
accuracy
Opis:
The paper presents a method combining the processes of straightening and thermal treatment. Technological processes with axial strain were considered, for the case of heated material and without its heating. The essence of the process in the case of heated material consisted in the fact that if under tension all longitudinal forces in the first approximation are uniform - the same strains are generated. The presented technological approach, aimed at reducing the curvature of axial-symmetrical parts, is acceptable as the process of rough, preliminary machining, in the case of shafts with the ratio L/D≤100 (L – shaft length, d – shaft diameter) and without a tendency of strengthening. To improve the accuracy and stability of geometric form of low-rigidity parts, a method was developed that combines the processes of straightening and heat treatment. The method consists in that axial strain – tension, is applied to the shaft during heating, and during cooling the product is fixed in a fixture, the cooling rate of the shaft being several-fold greater than that of the fixture. A device is presented for the realisation of the method of controlling the process of plastic deformation of low-rigidity shafts. In the case of the presented device and the adopted calculation scheme, a method was developed that permits the determination of the length of shaft section and of the time of its cooling.
Źródło:
Advances in Science and Technology. Research Journal; 2016, 10, 29; 62-70
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of Ball Screws for Feed Drive
Autorzy:
Sobolewski, J.
Powiązania:
https://bibliotekanauki.pl/articles/99865.pdf
Data publikacji:
2013
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
ball screws
machine tools
rigidity
impact forces
Opis:
The paper presents a method which enables the ball screw choice for machine tools feed drive with increasing cutting speed. It has been proven, that when the velocity deflection in the ball/balltrack area of the transitive phase of ball motion reaches a certain level, the repetitive shocks (impact forces) are generated. Digital simulation of these forces for variable length screws shaft and ball diameters in function of rotational speed has been performed. The research proves that impact forces increase not only as rotational velocity increases, but also with the increase of the ball diameters. The cases of the harmful accordance of the feed drive resonance vibrations with the frequency of the balls entering the load have been examined.
Źródło:
Journal of Machine Engineering; 2013, 13, 4; 86-95
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Use of functional cluster analysis of CPTU data for assessment of a subsoil rigidity
Autorzy:
Młynarek, Z.
Wierzbicki, J.
Wołyński, W.
Powiązania:
https://bibliotekanauki.pl/articles/178174.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
CPTU
cluster analysis
functional data
rigidity model
Opis:
This paper shows an example of the grouping of piezocone penetration test (CPTU) characteristics using functional data analysis, together with the results of clustering, in the form of a subsoil rigidity model. The subsoil rigidity model was constructed based on layer separation using the proposed method, as well as the k-means method. In the construction of the subsoil rigidity model, the constrained modulus M was applied. These moduli were determined from empirical relationships for overconsolidated and normally consolidated soils from Poland based on cone tip resistance.
Źródło:
Studia Geotechnica et Mechanica; 2018, 40, 2; 117-124
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wage-setting Behavior in France: Additional Evidence from an Ad-hoc Survey
Autorzy:
Montornes, Jeremi
Sauner-Leroy, Jacques-Bernard
Powiązania:
https://bibliotekanauki.pl/articles/565721.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet Warszawski. Wydawnictwo Naukowe Wydziału Zarządzania
Tematy:
wage rigidity
wage-setting behavior
survey data
Opis:
We investigate the wage-setting behavior of French companies using an ad-hoc survey specifically conducted for this study. Our main results are the following. i) Wages are changed infrequently. 75% of firms change their wages once a year. Wage changes occur at regular intervals during the year and are concentrated in January and July. ii) We find a lower degree of downward real wage rigidity and nominal wage rigidity in France compared to the European average. iii) About one third of companies have an internal policy to grant wage increases according to inflation. iv) When companies are faced with adverse shocks, the latter are partially transmitted into prices. Companies also adopt cost-cutting strategies. The wage of newly hired employees plays an important role in this adjustment.
Źródło:
Journal of Banking and Financial Economics; 2015, 1(3); 5-23
2353-6845
Pojawia się w:
Journal of Banking and Financial Economics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Simulation Studies on the Process of Machining of Shafts with Low Rigidity
Autorzy:
Świć, A.
Gola, A.
Powiązania:
https://bibliotekanauki.pl/articles/117946.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Promocji Wiedzy
Tematy:
turning
shaft with low rigidity
numerical simulation studies
Opis:
The paper presents a computer program developed for the determination of the basic dynamic characteristics of the process of machining, numerical simulations of the dynamic system of the process of machining, and graphic presentations of the numerical simulations performed. Results of simulations of the runs of time and frequency characteristics of the process of machining with variable machining parameters are presented. High goodness-of-fit of the model with the actual process of turning was achieved.
Źródło:
Applied Computer Science; 2016, 12, 2; 42-53
1895-3735
Pojawia się w:
Applied Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mathematical model of flexible link dynamics in marine tethered systems considering torsion and its influence on tension force
Autorzy:
Trunin, Konstantin
Powiązania:
https://bibliotekanauki.pl/articles/32922104.pdf
Data publikacji:
2023
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
underwater tethered system
flexible links
rigidity
submersible vehicle
Opis:
The rigidity in bending of a flexible link (is an important characteristic that should be considered during regular service conditions. The tension and bending with torsion of wire ropes are also significant factors. This study proposed a method to calculate the vectors of the generalised forces of bending of flexible links. One of the causes of torsional stresses in the power plant of underwater tethered systems is the interaction with ship equipment, such as spiral winding on the winch drum, friction on the flanges of the pulleys or winch drums, and bends on various blocks and rolls that cause torsion. The source of torsional stresses in the FL may also be related to manufacturing, storage, transportation, and its placement on the ship’s winch drums. Torsion can lead to a decrease in the tensile strength due to load redistribution between power elements, or even a violation of their structure. In some cases, torsion significantly affects the movement of the underwater tethered system as a whole. The development of a mathematical model to describe the marine tethered systems dynamics, taking into account the effect of torsion, is important and relevant. The mathematical model of the marine tethered systems dynamics was improved and solved by accounting for the generalised forces of the torsion rigidity of the flexible link, using an algorithm and computer program. The influence of the bending and torsional rigidity of the FL on its deflection and tensile strength were considered based on the example of two problems. The developed program’s working window image shows the simulated parameters and the initial position of the flexible link. The results show that torsion has almost no effect on the shape of the a flexible link’s deflection in the X0Z plane, but leads to a deviation from the X0Z plane when calculating the static deflection of the flexible link. When the carrier vessel is stationary and the submersible vehicle has no restrictions on movement and has positive buoyancy, torsion leads to a three-dimensional change in the shape of the flexible link both in the X0Z plane and in the X0Y plane. The tension force of the flexible link along its length is distributed unevenly, and the torsion of the flexible link can lead to significant changes in its shape, the trajectory of towed objects, and the forces acting on the elements of the marine tethered systems.
Źródło:
Polish Maritime Research; 2023, 2; 188-196
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Finite element analysis of the dynamically created portal in the huge machine tool of “travelling column” type
Autorzy:
Dounar, Stanislau
Iakimovitch, Alexandre
Jakubowski, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/1818876.pdf
Data publikacji:
2021
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
FEA
portal
travelling column
rigidity
resonance
torsion
pecking
Opis:
In this paper, a special configuration for the huge multipurpose machine tool of “travelling column” type was investigated by the finite element analysis. Internal degrees of freedom of a bulky system consisting of the ram, stock, column, sledge and bed, were implemented by the hydrostatic guides. A simulation of coupling two assembled columns into the portal structure was completed. The results of this work showed that temporal joining raises the spindle static rigidity by 1.39–1.91 times depending on the direction (mostly longitudinal – along the X-axis). The simulation also revealed the robustness of a whole-machine resonance pattern (11.7–39.0 Hz) to “column–to–portal coupling”. Eight types of eigenmodes were analyzed for frequency intervals from 0 to 80 Hz. A decrease by 2.9 times of the resonance peaks of a frequency response function was observed in the case of a portal structure creation. In case of columns-to-portal transition, stable cutting just at resonance frequencies (resonance overriding) becomes allowable. Overall, the “Portal” structure is recommended for intermittent cutting machining by raised high spindle unit at frequencies below 40 Hz.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2021, 65 (137); 29-37
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Technology of heat treating-straightening of long shafts with low rigidity
Autorzy:
Świć, A.
Draczew, O
Gola, A.
Powiązania:
https://bibliotekanauki.pl/articles/103297.pdf
Data publikacji:
2016
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
heat treating-straightening
long shaft with low rigidity
Opis:
The paper presents a new method of heat treating-straightening of long shafts with low rigidity. Analytical relationships for the determination of rectilinearity of shaft axis in heat treating-straightening are presented. A fixture for heat treating-straightening of shafts was developed. The experiment conducted as well as the calculations confirm high effectiveness of the developed method of heat treating-straightening of long shafts with low rigidity. Application of the developed technology of heat treating-straightening permits minimisation of the value of deflection of semi-finished product and stabilisation of the level of residual longitudinal stress, which results in enhanced operational accuracy of long shafts with low rigidity, improved quality and operation parameters of finished products.
Źródło:
Advances in Science and Technology. Research Journal; 2016, 10, 31; 207-214
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of sowing density on the lodging and mechanical properties of rape stalks
Autorzy:
Skubisz, G.
Powiązania:
https://bibliotekanauki.pl/articles/25470.pdf
Data publikacji:
1996
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
oilseed rape
sowing density
stalk
rigidity
mechanical property
Źródło:
International Agrophysics; 1996, 10, 4
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulation investigation of ball screws for high speed transmitting systems
Autorzy:
Sobolewski, J. Z.
Małkiński, J.
Pieniecki, P.
Powiązania:
https://bibliotekanauki.pl/articles/1429177.pdf
Data publikacji:
2008
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
ball screw
CNC feed systems
rigidity
impact force
Opis:
The ball screws are used in feed systems in CNC machines working with constantly higher cutting speed. When the speed of the balls reaches certain levels, the repetitive chock (impact forces) generated by the balls in the "transient" phase of the balls' motion and forces acting in the return channel cause damage to the recirculation ball system. A simulation of impact forces for variable length of transient phase in function of the rotational speed was made. The static axial rigidity is a very important factor to be considered in defining ball screws performance and exerts a major influence on positioning accuracy of NC machine tools. One of rigidity components is the balls/balltrack area rigidity, dependent on Hertz's deflections. However, due to machining inaccuracies, the ball screws properties (especially rigidity) are considerably lower than the theoretical ones. A coefficient known as the geometric correction factor makes it possible to predict the rigidity of the ball screw. A computer simulation of the influence of machining inaccuracies on contact deflections, rigidity and servo drive resonance was carried out. It was examined what rotational speeds set off the harmful phenomenon of the agreement of the frequency of the arrangement of the impact forces with the frequency of the servo drive system resonance. The presented method allows for the calculation of the impact forces, total rigidity and resonance of NC machine feed system, in the preliminary phase of technical project.
Źródło:
Journal of Machine Engineering; 2008, 8, 4; 59-67
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic finite element analysis of rotor-shaft fastening into a heavy precise lathe
Autorzy:
Dounar, Stanislau
Jakubowski, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/1818744.pdf
Data publikacji:
2021
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
finite element analysis (FEA)
lathe
rotor
renovation
rigidity
reinforcement
Opis:
The results of finite element analysis of large machined rotor fastened into heavy precise lathe are reported. Many design changes are simulated to improve the dynamic rigidity of the machining. Three radial eigenmodes detrimental to the accuracy were revealed: rotor-stock bending at 17.7 Hz (“half-wave”), rotor-lathe bending at 36.1 Hz (“full-wave”), and “support rocking” at 68.1 Hz. The frequency response functions and dynamic rigidities were evaluated. Three compliance issues were revealed: angular flexibility of the spindle console, low stiffness of the lathe bed (with boots), and an excessively slender tailstock. It is proposed to transform the spindle chuck into a table with additional hydrostatic backing, fill the bed cavities with concrete, and redesign the tailstock as a counter-spindle unit. This will decrease the amplitude of the main rotor resonance by 6.3 times and upshift the frequency near two-fold from 17.7 to 35 Hz. The renovated lathe should be able to machine a rotor without a lunette system or overriding the main resonant frequency.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2021, 66 (138); 37-45
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Degree of monopoly and market power vs. price flexibility in Polish economy: empirical analysis based on COICOP classification
Autorzy:
Umiński, Paweł
Powiązania:
https://bibliotekanauki.pl/articles/19233485.pdf
Data publikacji:
2020
Wydawca:
Instytut Badań Gospodarczych
Tematy:
degree of monopoly
market power
price rigidity
COICOP
Polska
Opis:
Research background: The issue of price flexibility is crucial in the economy both in the aspect of company theory and its macroeconomic consequences. In a number of publications, the sources of variable price flexibility are linked to the market power of enterprises as well as the market structure that has developed in a given branch. It is difficult to indicate empirical studies that would state clearly whether price flexibility depends on the degree of monopoly or the market power of enterprises. This paper concerns that particular field of study. Purpose of the article: The purpose of the paper is to present the statistical dependence of the degree of monopoly and market power vs. price flexibility in the economy. Methods: The analysis has been conducted using aggregated data concerning Polish economy in the period from 2001 to 2013, based on COICOP. The degree of monopoly indicator was the average number of companies in a given branch, following the classical models of market structures; the market power indicator was the average net revenue from sales of products per enterprise representing a given branch; the measure of price flexibility was the probability of price variation estimated using the Calvo pricing model. It is, therefore, a frequency-based approach to price flexibility. Statistical dependence was analyzed using the Spearman's rank and Kendall's tau correlation coefficient and simple regression models. Findings & Value added: The outcomes indicate that in the case of Poland in the analyzed period there is no statistically significant relation between the degree of monopoly and price flexibility and also between the market power and price flexibility. Thus, the findings of the analysis support the studies which reject the assumption that higher degree of monopoly or higher market power of an enterprise is followed by less flexible prices.
Źródło:
Oeconomia Copernicana; 2020, 11, 1; 11-28
2083-1277
Pojawia się w:
Oeconomia Copernicana
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 41

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies