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PL
W artykule przeprowadzono ocenę oprogramowania wykorzystywanego do nauki projektowania złożonych i wielkogabarytowych konstrukcji cienkościennych. Większość oferowanych środowisk graficznych umożliwia zamodelowanie struktury przestrzennej obiektu i przeprowadzenie badań symulacyjnych obejmujących np.: analizę wytrzymałościową i statyczną, obliczenia drgań własnych i wymuszonych. Moduł obliczeniowy w tego typu programach bazuje na metodzie elementów skończonych. W pracy zamieszczono przykładową ścieżkę projektową i analizę pokładu okrętu typu RO-RO, na którym zaparkował samochód ciężarowy. W przedstawionym przykładzie wykorzystano oprogramowanie firmy MSC z preprocesorem Patran i modułem obliczeniowym Nastran.
EN
In the paper the software to the teaching of designing of complex and large-scale thin-walled structures was evaluated by the authors. The bundle of MSC software, named Patran-Nastran, was presented. The software is based on Finite Element Method. The authors, during the teaching process, focus on basic analyses: linear static strength analysis, normal mode (eigenvectors) analysis and frequency response analysis (forced vibrations calculations). An example of RO-RO ship's deck analysis was presented. The deck was loaded with the wheels of truck. A short description of the modeling process as well as the results of the analyses are presented in the paper. Discussion about objectives of the teaching process was carried out. In the authors' opinion, knowledge of that very specialized software is important not only for a calculating engineer. All mechanical engineers should have basic knowledge about the calculations process because they will be recipients of the calculations performed during structure designing. Thin-walled structures are very useful for teaching because during the structure modeling we have to choose types of FEM elements. Stiffeners may be modeled by 1-D elements (with offset) and the plates should be modeled by 2D elements. Differences between beam and rod 1D elements as well as shell, plate and membrane 2D elements should be stressed during the teaching process.
EN
It is widely known that lateral-torsional buckling of a member under bending and warping restraints of its cross-sections in the steel structures are crucial for estimation of their safety and durability. Although engineering codes for steel and aluminum structures support the designer with the additional analytical expressions depending even on the boundary conditions and internal forces diagrams, one may apply alternatively the traditional Finite Element or Finite Difference Methods (FEM, FDM) to determine the so-called critical moment representing this phenomenon. The principal purpose of this work is to compare three different ways of determination of critical moment, also in the context of structural sensitivity analysis with respect to the structural element length. Sensitivity gradients are determined by the use of both analytical and the central finite difference scheme here and contrasted also for analytical, FEM as well as FDM approaches. Computational study is provided for the entire family of the steel I- and H - beams available for the practitioners in this area, and is a basis for further stochastic reliability analysis as well as durability prediction including possible corrosion progress.
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