Wyniki wyszukiwania - Biblioteka Nauki

1

Shear lag effect in the numerical experiment

100%

Szumigała M. , Ciesielczyk K.

|

tom Vol. 61, nr 3

31--50

EN

The standard PN-EN 1993-1-5:2008 (Eurocode 3) compared with the standard (PN-B-03200:1990) used previously in Poland, introduces extended rules referring to the computations of the bearing capacity of the plated structural elements including the shear lag effect. The stress distribution in the width flanges is variable. Therefore in the case of the beam with the shear lag effect cannot be calculated by the classic beam theory. In this article a comparison of the results of the calculations of forces distribution, stresses and displacement according to the rule presented in PN-EN 1993 and results of the numerical computations for 3D model (using finite element method) is presented. The elastic shear lag effects, the elastic shear lag effects including effects of the plate buckling and the elastic-plastic shear lag effects including the local instabilities were analysed. The calculations were performed for beams with a small and a large span and an influence of stiffeners was analysed.

PL

Norma PN-EN 1993-1-5:2008 (Eurocode 3) w porównaniu do dotychczas obowiązującej w Polsce normie dotyczącej projektowania konstrukcji stalowych (PN-B-03200:1990) wprowadza rozszerzone zasady obliczania nośności konstrukcji blachownicowych o uwzględnianie efektu „szerokiego pasa”. Rozkład naprężeń w szerokich pasach jest zmienny i z tego powodu w przypadku belek podlegających efektowi szerokiego pasa nie można przeprowadzać obliczeń według klasycznej teorii belkowej. W artykule można wyróżnić dwie główne części: pierwszą zawierającą wstęp oraz teoretyczny opis podstaw dotyczących szerokości efektywnej i efektu szerokiego pasa (rozdziały pierwszy i drugi) oraz drugą przedstawiającą wyniki obliczeń analitycznych i numerycznych wpływu efektu szerokiego pasa na rozkład sił wewnętrznych (rozdziały trzeci i czwarty). W rozdziale piątym przedstawione zostały wnioski z przeprowadzonych analiz.

2

Local and distortional buckling of axially loaded cold rolled sigma profiles

100%

Ciesielczyk K. , Rzeszut K.

|

tom Vol. 10, no. 3

218--222

EN

In this paper the local and distortional buckling analyses of axially loaded cold-rolled channel and sigma profiles were performed. The critical buckling load was computed by solving the linear eigenvalue problem for different numerical models using Finite Element Method and simplified formulas implemented in Eurocode and proposed by Hancock and Schafer. The buckling analyses were conducted to prove that the sigma cross-section can be successfully replaced by channel cross-section with additional elastic supports placed in folds of the web. It was demonstrated that the folds in the web of the sigma cross-section (additional elastic supports) reduce the slenderness of the web. So, the critical distortional stress can be calculated based on analytical formulas derived for the channel crosssection taking into account the web height between the folds.

3

Determination of thermal conductivity coefficient by Green-Kubo formula using the minimum image method

80%

Hyżorek K. , Ciesielczyk K. , Tretiakov K. V.

|

tom Vol. 25, No. 2

99--103

EN

The thermal conductivity coefficients of solid argon have been evaluated by equilibrium molecular dynamic simulations. A Lennard-Jones interatomic potential has been used to model the interactions between argon atoms. In simulations and calculations of the thermal conductivity by the Green-Kubo formula, the long-range interactions between atoms have been taken into account using the minimum image method (MIM). The study shows that there are no significant differences between the values of the thermal conductivity obtained by method using MIM and those coming from traditional Green-Kubo approach. Both experimental data and results of molecular dynamics simulations are also in agreement with the Klemens-Callaway model for the thermal conductivity based on the three-phonon Umklapp scattering.

4

Urinary neutrophil gelatinase-associated lipocalin, kidney injury molecule-1, uromodulin, and cystatin C concentrations in an experimental rat model of ascending acute kidney injury induced by pyelonephritis

51%

Skowron B. , Baranowska A. , Dobrek L. , Ciesielczyk K. , Kaszuba-Zwoinska J. , Wiecek G. , Malska-Wozniak A. , Strus M. , Gil K.

|

nr 4