Wyniki wyszukiwania - BazTech

1

Simplified procedure for the free vibration analysis of rectangular plate structures with holes and stiffeners

Cho D. S., Vladimir N., Choi T. M.

Polish Maritime Research

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2015

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nr 2

71--78

EN

Thin and thick plates, plates with holes, stiffened panels and stiffened panels with holes are primary structural members in almost all fields of engineering: civil, mechanical, aerospace, naval, ocean etc. In this paper, a simple and efficient procedure for the free vibration analysis of such elements is presented. It is based on the assumed mode method and can handle different plate thickness, various shapes and sizes of holes, different framing sizes and types as well as different combinations of boundary conditions. Natural frequencies and modes are determined by solving an eigenvalue problem of a multi-degree-of-freedom system matrix equation derived by using Lagrange’s equations. Mindlin theory is applied for a plate and Timoshenko beam theory for stiffeners. The applicability of the method in the design procedure is illustrated with several numerical examples obtained by the in-house developed code VAPS. Very good agreement with standard commercial finite element software is achieved.

2

The transition effect in rail tracks – assessment of transient energy for low frequency vibrations

Sołkowski J.

Archives of Civil Engineering

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2014

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Vol. 60, nr 1

123--143

EN

The transition effect between different track-foundation systems is examined from the point of view of energy that is produced during the passage of load. Analytical solution is given. A model of beam on elastic foundation with damping is used as the base model. It is developed into a model composed of two parts that represent the track-subgrade system with an abrupt change in mechanical parameters: bending stiffness, foundation stiffness, damping, and mass. Several calculations are carried out including examples of comparative calculations with the Finite Difference Model and the Finite Element Model. Transient rail deflections and energy are determined, which may serve to estimate the rate of track-subgrade deterioration.

3

Fatigue life estimation on notched specimens under bending and torsion with strain energy density parameter

Łagoda T., Ogonowski P.

Journal of Theoretical and Applied Mechanics

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2007

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Vol. 45 nr 2

349-361

EN

This paper presents an energy damage parameter based on the critical pIane under a complex loading state and stress concentration. Two criteria including combinations of the normaI and shear strain energy density parameters have been proposed. The pIane in which the normaI or shear strain energy density parameter reaches its maximum is assumed to be the critical pIane. The predictions of the proposed model have been compared with constant amplitude fatigue tests under combined proportional bending and torsion carried out on ring-notched specimens made of 42CrMo4V steel.

PL

W pracy przedstawiono energetyczny parametr uszkodzenia oparty na płaszczyźnie krytycznej w warunkach złożonego stanu obciążenia i spiętrzenia naprężeń. Zaproponowano dwa kryteria uwzględniające kombinacje parametrów gęstości energii odkształcenia normalnego i postaciowego. Za płaszczyznę krytyczną przyjęto płaszczyznę, w której parametr gęstości energii odkształcenia normalnego lub postaciowego osiąga wartość maksymalną. Wyniki obliczeń uzyskane za pomocą zaproponowanego modelu porównano z wynikami stałoamplitudowych badań zmęczeniowych próbek ze stali 42CrMo4V z karbem obrączkowym wykonanych w warunkach kombinacji proporcjonalnego zginania ze skręcaniem.

4

Estimation of high temperature fatigue lifetime of SUS304 steel with an energy parameter in the critical plane

Łagoda T., Macha E., Sakane M.

Journal of Theoretical and Applied Mechanics

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2003

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Vol. 41 nr 1

55-73

EN

The paper studies the application of the energy parameter, a sum of elastic and plastic strain energy densities in the critical plane, for the correlation of two series of proportional biaxial low-cycle lives using SUS304 stainless steel at elevated temperature. The first data used thin-walled cylinder specimens subjected to 7 proportional strain paths of combined tension-torsion and the other used cruciform specimens subjected to 5 proportional strain paths of biaxial tension-compression. These tests were done at the temperature of 923 K. The normal total strain energy density in the plane with the maximum damage was a suitable parameter for describing the test results.

PL

Praca dotyczy zastosowania parametru energetycznego, sumy gęstości energii sprężystej i plastycznej odkształcenia w płaszczyźnie krytycznej do korelacji dwóch serii proporcjonalnych, dwuosiowych, niskocyklowych trwałości zmęczeniowych stali nierdzewnej SUS303 w podwyższonej temperaturze.Badano cienkościenne próbki cylindryczne poddane siedmiu proporcjonalnym torom odkształcenia w warunkach kombinacji rozciągania-skręcania oraz próbki krzyżowe poddane pięciu proporcjonalnym torom odkształcenia w warunkach dwuosiowego rozciągania-ściskania. Badania prowadzono w temperaturze 923 K. Gęstość energii całkowitego odkształcenia normalnego w płaszczyźnie maksymalnego uszkodzenia była odpowiednim parametrem do opisania wyników badań.

5

Energy approach to fatigue life estimation under combined tension with torsion

Łagoda T., Macha E.

Zeszyty Naukowe. Mechanika / Politechnika Opolska

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2001

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z. 67

163-182

EN

The paper concerns application of the energy parameter, being a sum of the elastic and plastic strain energy density in the critical plane, for description of experimental data obtained from the fatigue tests of 35NCD16 steel, GGG40 and GGG60 cast irons subjected to constant amplitude cyclic tension-compression, torsion and variable-amplitude tension-compression, torsion and combined tension with torsion. It has been shown that the parameter of specific work of selected stress on selected strains in the critical plane is an efficient parameter expressing the fatigue life of analysed materials under the considered kinds of loading. The critical plane is the plane where the parameter of normal strain energy density reaches its maximum.