Wydział Mechaniczny / Faculty of Mechanical Engineering / W1
Stały URI zbioruhttp://hdl.handle.net/11652/1
Przeglądaj
8 wyniki
Wyniki wyszukiwania
Pozycja Post-ultimate behaviour of thin-walled cold-formed steel open-section members in pure and eccentric compression(Wydawnictwo Politechniki Łódzkiej, 2016) Dubina, Dan; Kotełko, Maria; Ungureanu, ViorelThis chapter is a review of research in recent years as a result of collaboration between the Department of Steel Structures and Structural Mechanics of Politehnica University of Timisoara and Department of Strength of Materials of Łódź University of Technology related to a load carrying capacity, post-failure behaviour and plastic mechanisms of failure of thin-walled cold-forms steel (TWCFS) members subjected to compression and/or bending.Pozycja Elasto-plastic behaviour and load-capacity of multi-layered plated structures(Lodz University of Technology Press, 2016) Grądzki, Ryszard; Kotełko, Maria; Mania, Radosław, J.This chapter is a review of research realized in last decade mainly in collaboration with the late Professor Katarzyna Kowal-Michalska in the domain of elasto-plastic behaviour and ultimate strength of multi-layered plated structures.Pozycja Advanced mechanical engineering : (with elements of numerical engineering analysis)(Wydawnictwo Politechniki Łódzkiej, 2006) Kotełko, Maria; Kubiak, Tomasz; Scientific Editor of the Division : Kapitaniak, Tomasz; Niezgoda, Tadeusz; Zielnica, Jerzy[...] The book is divided into three parts: the first one contains the foundations of mechanics of solids (particularly of the theory of elasticity) including the stress and strain analysis (concept of the stress and strain tensor in the rectangular co-ordinate system, as well as constitutive stress-strain relations for the general case of elastic anisotropic materials. The first part provides also a reader with a knowledge of yield criteria of not only ductile , isotropic material but also of modern orthotropic materials. The first part concludes with the energy methods in mechanics of materials. Although this part is devoted to advanced topics of mechanics of materials it contains as well some very basic problems (like the concept of equivalent stress for combined load) since they are not included into the syllabus of prerequisite subjects of Basic Mechanical Engineering I and II delivered to the students of Mechanical Engineering and Applied Computer Science (IFE), to whom the book is devoted mainly. The second part contains the theoretical foundations of the Finite Element Method, preceded with the description of the general concept of FEM and the short review of matrix algebra. Afterwards, the basic types of finite elements are discussed and their stiffness matrices are derived. The last part is devoted to selected advanced problems of mechanics of materials, including bending of thin plates, axi-symmetrical problems of the theory of elasticity and very basic introduction to the analyses of buckling of structural members. Each problem is discussed on the basis of analytical methods and simultaneously examples of numerical FE solutions are presented. In the section dealing with bending of rectangular plates the finite difference method is presented as an example of another, alternative numerical method that can be used in mechanics of materials. The third part concludes with the short chapter introducing a reader the problems of fatigue of structures. Some of the discussed topics are illustrated using exemplary problems with detailed solutions. However, the authors assume that a reader can find more of such problems in special text-books containing collections of problems of mechanics of materials to be solved.Pozycja Sensitivity Analysis of Steel Box-Section Girders.(Lodz University of Technology. Faculty of Mechanical Engineering. Department Division of Dynamics., 2013) Lis, Paweł; Kotełko, MariaThe paper deals with the load–carrying capacity stochastic variance based sensitivity analysis of thin–walled box–section girder subjected to pure bending. The lower– and uppe-r-bound load–capacity estimation is performed. The methodology is based on the Monte-Carlo method . The exemplary results are presented in diagrams and pie charts showing the sensitivity of load–capacity to different random input variables. The analysis is focused on the variance of the yield stress of the girder material and girder’s wall thickness. Some final conclusions, concerning an efficiency of the applied models and the sensitivity analysis are derived.Pozycja Numerical and experimental collapse analysis of tubular multi-member energy absorbers under lateral compression(Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej, 2004) Lipa, Sebastian; Kotełko, MariaIn the paper, the problem of collapse load and energy dissipation capacity of tubular multi-member energy absorbers subject to lateral crushing load is presented. The method of analytical solution of the problem of initial collapse load and load capacity at failure both for single-member and multi-member absorbers is discussed. A numerical Finite Elelment (FE) model of the multi-member absorber is presented and the parametric study of the influence of different absorber parameters (number of members, thickness of tubes, configuration of tubes) upon the collapse load and energy dissipation capacity is carried out. Results of numerical calculations are compared with those obtained from the experiment conducted by the authors. Both numerical and experimental results are presented in the form of load-deformation diagrams and diagrams of deformation patterns. Some final conclusions concerning the usefulness of multi-member tubular absorbers and indications into further investigations are derived.Pozycja Lateral impact of tubular structure - theoretical and experimental analysis. Pt.1 - Investigation of single tube.(Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej, 2013) Lipa, Sebastian; Kotełko, MariaIf a thin-walled member is subjected to dynamic load, the estimation of its structural behaviour has to count for the strain-rate influence upon stress-strain material characteristics. It is particularly important when a thin-walled member works as an energy absorber. In the paper, the problem of collapse load, post-failure behaviour and energy dissipation of a tubular structure subjected to lateral impact load is presented. The analytical solution of the problem of initial collapse load and post-failure behaviour of a single tube is discussed. The analysis is limited to the “dynamic progressive crushing”, which means that we take into account the strain-rate but neglect inertia effects. The solution is based on the yield-line analysis and takes into account the impact velocity and strain rate, using the Cowper-Symonds constitutive relation. The same problem concerning both the single tube and multi-member tubular structure subjected to lateral bending impact load is solved using Finite Element (FE) simulation, which also takes into account the impact velocity and strain rate, using the corresponding to Cowper-Symonds Perzyna material model. Results of numerical calculations are compared with those obtained from the quasi-dynamic tests performed at different loading velocities on single tubes. The results are shown in load-deformation diagrams and diagrams of deformation patterns.Pozycja Sensitivity analysis of steel box-section griders(Politechnika Łódzka. Katedra Wytrzymałości Materiałów i Konstrukcji, 2012) Kotełko, Maria; Lis, PawełPozycja Collaborative research on thin-walled structures by the University of Strathclyde and the Technical University of Lodz(Politechnika Łódzka. Katedra Wytrzymałości Materiałów i Konstrukcji, 2012) Macdonald, M.; Kotełko, Maria; Rhodes, J.; Zaraś, Jan