Tytuł Data publikacji Autor
Przedmiotem niniejszego opracowania jest obciążenie próbne wiaduktu 0-1 przeprawy drogowej przez rzekę Wisłę w ciągu Północnej Obwodnicy Puław. Opracowanie zawiera wyniki badań obiektu podczas próbnego obciążenia oraz analizę porównawczą i weryfikację wyników teoretycznych i wyników badań.
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Jacek Chróścielewski,
Maciej Malinowski,
Mikołaj Miśkiewicz,
Roman Rutkowski,
Tomasz Rutkowski
The investigation concerns local buckling of compressed flanges of axially compressed composite channel columns. Cooperation of the member flange and web is taken into account here. The buckling mode of the member flange is defined by rotation angle a flange about the line of its connection with the web. The channel column under investigation is made of unidirectional fibre-reinforced laminate. Two approaches to member orthotropic material modelling are performed: the homogenization with the aid of theory of mixture and periodicity cell or homogenization upon the Voigt–Reuss hypothesis. The fundamental differential equation of local buckling is derived with the aid of the stationary total potential energy principle. The critical buckling stress corresponding to a number of buckling half-waves is assumed to be a minimum eigenvalue of the equation. Some numerical examples dealing with columns are given here. The analytical results are compared with the finite element stability analysis carried out by means of ABAQUS software. The paper is focused on a close analytical solution of the critical buckling stress and the associated buckling mode while the web–flange cooperation is assumed.
2020
Czesław Szymczak,
Marcin Kujawa
The paper addresses the issue of local buckling of compressed flanges of cold-formed thin-walled channel columns and beams with nonstandard flanges composed of aluminium alloys. The material behaviour follows the Ramberg–Osgood law. It should be noted that the proposed solution may be also applied for other materials, for example: stainless steel, carbon steel. The paper is motivated by an increasing interest in nonstandard cold-formed section shaping in local buckling analysis problems. Furthermore, attention is paid to the impact of material characteristics on buckling stresses in a nonlinear domain. The objective of the paper is to propose a finite element method (FEM) model and a relevant numerical procedure in ABAQUS, complemented by an analytical one. It should be noted that the proposed FEM energetic technique makes it possible to compute accurately the critical buckling stresses. The suggested numerical method is intended to accurately follow the entire structural equilibrium path under an active load in elastic and inelastic ranges. The paper is also focused on correct modelling of interactions between sheets of cross section of a possible contact during buckling analysis. Furthermore, the FEM results are compared with the analytical solution. Numerical examples confirm the validity of the proposed FEM procedures and the closed-form analytical solutions. Finally, a brief research summary is presented and the results are discussed further on.
2020
Marcin Kujawa
The paper includes a case study of modelling a real historic church using the finite element method (FEM) based on laser scans of its geometry. The main goal of the study was the analysis of the causes of cracking and crushing of masonry walls. An FEM model of the structure has been defined in ABAQUS. A non-linear dynamic explicit analysis with material model including damage plasticity has been performed. A homogenization procedure has been applied to obtain the material parameters used in the modelling of masonry. In the numerical analysis, the interactions between the church structure, the foundations and the ground were taken into account. The obtained results match well with the damaged area of the entire structure from the in-situ survey, and it should be highlighted that the proposed FEM model allows for a rather precise identification of the causes and effects of cracking walls in a qualitative sense. Also a brief research summary is presented.
2020
Marcin Kujawa,
Izabela Lubowiecka,
Czesław Szymczak
We discuss a homogenized model of a pantographic bar considering flexoelectricity. A pantographic bar consists of relatively stiff small bars connected by small soft flexoelectric pivots. As a result, an elongation of the bar relates almost to the torsion of pivots. Taking into account their flexoelectric properties we find the corresponding electric polarization. As a results, the homogenized pantographic bar demonstrates piezoelectric properties inherited from the flexoelectric properties of pivots. The effective stiffness properties of the homogenized bars are determined by the geometry of the structural elements and shear stiffness whereas the piezoelectric properties follow from the flexoelectric moduli of the pivots.
2020
Victor Eremeev,
Jean-François Ganghoffer,
Violetta Konopińska-Zmysłowska,
Nikolay Uglov
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