Wydział Mechaniczny / Faculty of Mechanical Engineering / W1
Stały URI zbioruhttp://hdl.handle.net/11652/1
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Pozycja Wpływ modułu sprężystości postaciowej na stateczność płyt trójwarstwowych(Katedra Wytrzymałości Materiałów i Konstrukcji, Politechnika Łódzka, 2003) Mania, R.W pracy podano wyniki analizy stateczności globalnej płyt trójwarstwowych w kształcie trapezu równoramiennego swobodnie podpartych na całym obwodzie, poddanych osiowemu ściskaniu. Omówiono szczególny wpływ materiału rdzenia - jego modułu odkształcenia postaciowego - na wybór modelu płyty dla rozwiązania zagadnienia stateczności oraz na poziom obciążenia krytycznego płyty. Zamieszczono i omówiono wyniki rozwiązania analitycznego i rozwiązania numerycznego metodą elementów skończonych.Pozycja Numeryczna analiza zniszczenia absorbera energii zbudowanego z rur cienkościennych poddanych zgniotowi(Katedra Wytrzymałości Materiałów i Konstrukcji, Politechnika Łódzka, 2003) Kotełko, M.; Lipa, S.W pracy przedstawiono zagadnienie nośności w fazie zniszczenia absorbera energii zbudowanego z rur cienkościennych poddanych bocznemu (promieniowemu) zgniotowi. Omówiono metody analizy fazy zniszczenia absorberów energii. Przedstawiono model obliczeniowy metody elementów skończonych (MES) oraz wyniki obliczeń numerycznych MES. Przeprowadzono analizę wpływu liczby elementów rurowych i ich wymiarów oraz sformułowano wstępne wnioski dotyczące tego wpływu na nośność w fazie zniszczenia i ilość energii dysypowanej przez absorber. Wyniki obliczeń MES przedstawiono w postaci wykresów obciążenia w funkcji odkształcenia absorbera oraz map odkształceń i naprężeń.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 Elastooptyka i metoda elementów skończonych w mechanice pękania : wybrane problemy(Wydawnictwo Politechniki Łódzkiej, 2007) Niezgodziński, Tadeusz; Red. nauk. Wydziału: Kapitaniak, Tomasz; Kołakowski, Zbigniew; Niezgoda, TadeuszThe book contains results of numerical calculation and their comparison with experimental tests carried out on the specimens CT. Crack propagate until damage specimen was achieved. The angle between the direction of crack propagation and the direction of the artificial crack was measured. Author during numerical investigations compare Burzynski and Huber-MisesHencky hypothesis. The Burzynski hypothesis gives very good results for brittle materials which has different properties for tensile and compression it means that relationship between limit stress for compression Re to limit stress for tension Rm is greater than 1 (for example: epoxy resign, cast iron). Influence of relation R.!Rm on angle of crack propagation was carried out. The results of investigation gives information that for relation R.!Rm greater than 1,3 the value of angle of crack propagation is constant, and its value is about 76°. The experimental investigation is solved by photoelastic method. The numerical results were obtained using finite element method package ANSYS. The problem is solved by "element birth and death" method. Results of investigations of cracking of reinforced specimens are presented.Pozycja Effect of changes in the thickness of a perforated plate of the heat exchanger on its structural stability.(Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej, 2004) Chudzik, Agnieszka; Świniarski, JacekOne of the most important elements of heat exchangers are perforated bottoms. These are perforated plates of significant thickness, in which heating cartridge pipes are mounted. For the designers of heat exchangers, the strength analusis of the connection between the elements, which allows for the determination of the state of stress and calculation of displacements of the perforated bottom after fixing the pipes in it, is of special importance. It results from carried out computations that the maximum reduced stresses in the perforated bottom are significantly lower than the values of admissible stresses. In this paper, computations of stresses and strains for various thicknesses of the perforated bottom have been presented. As a results of a decrease in the thickness of the perforated bottom, its deflectionincrease, and thus the heating system pipes are more exposed to strains and losses of stability.