Wyniki wyszukiwania - BazTech

1

Structural Optimization of Multimodal Routes for Cargo Delivery

Taran Ihor, Olzhabayeva Raushan, Oliskevych Myroslav, Danchuk Vitor

Archives of Transport

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2023

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Vol. 67, iss. 3

49--70

EN

This article is devoted to the coordination of single stages of the multimodal delivery process, taking into account the fact that the process is discrete in its content. The tact, which has the content of a time window for performing the operation is used for discrete processes. Due to the fact that multimodal transportation of goods is carried out on a large network, time is one of the most important criteria for their perfection. Two timing criteria are applied in the article, which take into account the fact that the multimodal process must be synchronized and that the transportation of a large group of goods can be carried out in separate parts. An estimation criterion was also applied, which takes into account constant, variable, contingent costs, which are carried out depending on the structure of the process. The goal of the study is to create such multimodal cargo delivery routes that are characterized by the highest level of selection criteria. In contrast to known studies, the dependence of the optimization criteria of the multimodal process on the total volume of cargo delivery was shown. The method of analyzing the transport scheme of multimodal transportation and the corresponding algorithm and computer program were developed. The methodology involves a complete review of all possible route options using three types of continent transport, namely road, rail, and river. The method of structural optimization is applied to the example of a transcontinental transport corridor.

2

Optimal design of Wire-and-Arc Additively Manufactured I-beams for prescribed deflection

Bruggi Matteo, Laghi Vittoria, Trombetti Tomaso

Computer Assisted Methods in Engineering and Science

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2022

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Vol. 29, no. 4

357--378

EN

Alloys fabricated by wire-and-arc additive manufacturing (WAAM) exhibit a peculiar anisotropy in their elastic response. As shown by recent numerical investigations concerning the optimal design of WAAM-produced structural components, the printing direction remarkably affects the stiffness of the optimal layouts, as well as their shape. So far, single-plate specimens have been investigated. In this contribution, the optimal design of WAAM-produced I-beams is addressed assuming that a web plate and two flat flanges are printed and subsequently welded to assemble the structural component. A formulation of displacement-constrained topology optimization is implemented to design minimum weight specimens resorting to a simplified two-dimensional model of the I-beam. Comparisons are provided addressing solutions achieved by performing topology optimization with (i) conventional isotropic stainless steel and with (ii) WAAM-produced orthotropic stainless steel at prescribed printing orientations. Lightweight solutions arise whose specific shape depends on the selected material and the adopted printing direction.

3

Contribution to random vibration numerical simulation and optimisation of nonlinear mechanical systems

Sága Milan, Vaško Milan, Handrik Marian, Kopas Peter

Zeszyty Naukowe. Transport / Politechnika Śląska

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2019

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z. 103

143--154

EN

This study considered the solution of the stochastic vibration of non-linear mechanical systems with Gaussian random excitations. It realised a short review of linearisations techniques in stochastic dynamics mainly with application in the area of truss finite element modelling. The presented method of statistical linearisation is applied to numerical testing. In the second part of the article, the sensitivity analysis of the first two stress statistical moments and structural weight minimising subjected to the random stress constrains presented by mean value and standard deviation was brought to the fore. Cross-sectional areas were used as optimising parameters.

4

Effective algorithm for structural optimization subjected to fatigue damage and random excitation

Sága M., Vaško M., Ságová Z., Handrik M.

Zeszyty Naukowe. Transport / Politechnika Śląska

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2018

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z. 99

149--161

EN

The aim of the paper is to present the computationally timeconsuming task of simulating the process of randomly oscillating thin-shell structures to realize an optimal design with limitations in terms of fatigue damage. The most important aim here is to design an effective optimization algorithm and choose an appropriate approach for the evaluation of multiaxial fatigue damage in the context of the random and non-proportional character of stress in the structure when considering the standard finite element model. The authors propose their own optimization algorithm, which is described in the present study and, on the basis of tests, has proven to be suitable for the aforementioned technical problems. The proposition of algorithms for calculating the accumulation of fatigue damage in non-proportional and multiaxial stresses (especially in terms of the application of rainflow analysis by decomposition of the equivalent stress, as determined by the appropriate “fatigue” criterion) is very important in such computational processes. The entire computational process was implemented in MATLAB with the “Discret_Opt_Fat” main control program. The article presents the theoretical basis for the presented complex problem solution, its algorithmization and the technical application.

5

Optimization of hydraulic crane prototype

Mysłek A., Sanecki H.

Symulacja w Badaniach i Rozwoju

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2017

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Vol. 8, nr 3-4

105--113

EN

The paper presents an application of research methodology leading to structural optimization of a crane model containing hydraulic cylinders. CAD and CAE systems were used to obtain a three-dimensional model of the crane and state of stresses and displacements, as well as to carry out appropriate optimization procedures. This issue is important from the point of view of full strength verification of modern transport equipment, particularly at the design stage, while detailed experimental research is not yet conducted.

PL

Praca prezentuje metodykę badań prowadzącą do optymalizacji strukturalnej żurawia zawierającego siłowniki hydrauliczne. Zastosowano systemy CAD i CAE do uzyskania trójwymiarowego modelu żurawia oraz stanu naprężeń i przemieszczeń, a także do przeprowadzenia odpowiednich operacji optymalizacyjnych. Zagadnienie jest istotne z punktu widzenia pełnej weryfikacji wytrzymałościowej nowoczesnych urządzeń transportu bliskiego zwłaszcza na etapie projektowania, gdy jeszcze nie prowadzi się szczegółowych badań doświadczalnych.

6

Structural optimization of internally reinforced beams subjected to uncoupled and coupled bending and torsion loadings for industrial applications

Silva H. M., Meireles J. F.

Mechanics and Mechanical Engineering

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2017

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Vol. 21, nr 2

329--351

EN

In this work, novel types of internally reinforced hollow-box beams were structurally optimized using a Finite Element Updating code built in MATLAB. In total, 24 different beams were optimized under uncoupled bending and torsion loads. A new objective function was defined in order to consider the balance between mass and deflection on relevant nodal points. New formulae were developed in order to assess the efficiency of the code and of the structures. The efficiency of the code is determined by comparing the Finite Element results of the optimized solutions using ANSYS with the initial solutions. It was concluded that the optimization algorithm, built in Sequential Quadratic Programming (SQP) allowed to improve the effective mechanical behavior under bending in 8500%, showing a much better behavior than under torsion loadings. Therefore, the developed algorithm is effective in optimizing the novel FEM models under the studied conditions.

7

Integration of reliability analysis into mini-plate fixation strategy used in human mandible fractures: Convalescence and healing periods

Kharmanda G., Shokry A., Kharma M. Y.

Acta of Bioengineering and Biomechanics

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2017

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Vol. 19, no. 4

13--23

EN

The objective was to assess the reliability level of mini-plate fixation used in fracture mandibles in order to evaluate the structure stability in both convalescence and healing periods. Methods: In the convalescence period, the failure scenario is measured by the relative displacement between two fracture surfaces which should not exceed an acceptable value in order to obtain a good stability for rapid bone healing and to limit any trauma. However, in the healing period, it is the objective to obtain an acceptable rigidity. Hereby, the failure scenario is measured by the von Mises stresses being as indicator of mandible fractures. Results: During the surgery operation, some muscles can be cut or harmed and cannot operate at its maximum capability. Thus, there is a strong motivation to introduce the loading uncertainties in order to obtain reliable designs. A 3-dimensional finite element model was developed in order to study the negative effect caused by stabilization of the fracture. The different results were obtained when considering a clinical case of a 35-year-old male patient. The results show the importance of fixation of symphysis fracture by two I-plates with four holes. The structural reliability level was estimated when considering a single failure mode and multiple failure modes. Conclusions: The integration of reliability concepts into mini-plate fixation strategy is considered a novel aspect. The reliability evaluation seams to be a reasonable asset in both convalescence and healing periods.

8

Comparative Analysis of Bionic and Geometrical Structural Forms

Gawell E., Nowak A., Rokicki W.

Journal Biuletyn of Polish Society for Geometry and Engineering Graphics

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2016

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Vol. 29

31--40

EN

In contemporary architecture is the rise of bionics as a source of inspiration in the development of unusual forms. The reason for such actions is both searching for new solutions, as well as the improvement of novelty in engineering design. There is a substantial interest in the field of bionics research in modern technology, also reflected in architecture. The attempt to render the morphology of the living organisms in the interaction of architectural and design can lead to optimal structural solutions, combining aesthetics with an expression of support and consistent static logic. At the same time, with the improvement of digital design tools it is possible to analyze technical solutions on many levels structural engineering. In modern architectural design the synergy of design solutions is an important field of activity for the people involved in the creative process. The search for efficient structural forms covered in the article is an attempt to discuss the optimization of load-bearing structures in the field of bionic morphology and geometry. The development of modern technologies enables the extension of the scope of the research, including the additional analysis dedicated to the interaction of the various fields of technology related to the evolution of architecture.

PL

We współczesnej architekturze widoczny jest wzrost znaczenia bioniki jako źródła inspiracji w kształtowaniu nietypowych form strukturalnych. Powodem takich działań jest zarówno poszukiwanie nowych rozwiązań plastycznych, jak również doskonalenie rozwiązań inżynierskich. Próba odwzorowania morfologii organizmów żywych we współdziałaniu architektoniczno-konstrukcyjnym może prowadzić do optymalnych rozwiązań strukturalnych, łączących estetykę z ekspresją techniczną i konsekwentną logiką statyczną. Jednocześnie dzięki doskonaleniu cyfrowych narzędzi projektowych możliwa jest analiza rozwiązań technicznych na wielu płaszczyznach inżynierii budowlanej. Poszukiwania efektywności from strukturalnych omówione w artykule stanowią dyskusję nad optymalizacją struktur nośnych w zakresie morfologii bionicznych i geometrycznych. Rozwój współczesnych technologii umożliwia poszerzenie zakresu badawczego, w tym o dodatkowe analizy poświęcone współdziałaniu poszczególnych dziedzin techniki związanych z kształtowaniem architektury.

9

Algorytmy stadne w optymalizacji strukturalnej systemów niezawodnościowych

Kwiecień J., Filipowicz B.

Przegląd Elektrotechniczny

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2014

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R. 90, nr 6

195--197

PL

W artykule przedstawiono zastosowanie algorytmów pszczelich i świetlika do wyznaczenia optymalnej struktury serwisu technicznego, w celu zapewnienia jego niezawodności oraz zminimalizowania kosztów związanych z jego funkcjonowaniem. Przedstawiono i porównano wyniki badań dla wybranych wygenerowanych problemów.

EN

This paper present the use of bee algorithms and firefly algorithm to determine the optimal structure of technical service, in order to ensure its reliability and to minimize the costs associated with its operation. The results of experiments for generated test instances are presented.

10

Optymalizacja strukturalna dla architektów

Pasternak A.

Kwartalnik Architektury i Urbanistyki

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2014

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T. 59, z. 2

63--66

PL

Poprzez porównanie etapów procesu projektowego w dziedzinie projektowania architektonicznego i projektowania samolotów, zwracając uwagę na sposób obsługi danych i integracji technik, uwidocznione zostały duże różnice w zakresie automatyzacji pewnych procesów projektowych. W projektowaniu architektonicznym, operowanie w takim środowisku, w którym możliwe jest tworzenie modeli parametrycznych, które w swojej logice mają zaprogramowane wytyczne, np. konstrukcyjne, umożliwi projektowanie budynków, których układ strukturalny i funkcjonalny są ze sobą lepiej zintegrowane i zoptymalizowane.

EN

A comparison of the phases of the design process in the field of architectural design and aircraft design, with particular consideration of the differences in data handling and technique integration, has shown large differences in the automation of certain design processes. In the field of architectural design, operating in an environment where it is possible to create parametric models in which logic guidelines such as construction guidelines are programmed, will allow designing buildings whose structural and functional layout are better integrated and optimized.

11

On some properties of bone functional adaptation phenomenon useful in mechanical design

Nowak M.

Acta of Bioengineering and Biomechanics

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2010

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Vol. 12, no. 2

49-54

EN

The paper discusses some unique properties of trabecular bone functional adaptation phenomenon, useful in mechanical design. On the basis of the biological process observations and the principle of constant strain energy density on the surface of the structure, the generic structural optimisation system has been developed. Such approach allows fulfilling mechanical theorem for the stiffest design, comprising the optimisations of size, shape and topology, using the concepts known from biomechanical studies. Also the biomimetic solution of multiple load problems is presented.

12

Optymalizacja strukturalna według wzorca biologicznego

Nowak M.

Górnictwo Odkrywkowe

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2006

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R. 48, nr 7-8

70-73

PL

Zaprezentowano metodę optymalizacji strukturalnej według wzorca biologicznego. Zjawiskiem biologicznym, na którym bazuje opisana metoda, jest adaptacyjna przebudowa kości beleczkowej. Przedstawiono zarówno wyniki symulacji adaptacji struktur kostnych, jak też algorytm optymalizacji strukturalnej przydatny, w projektowaniu mechanicznym.

EN

In the paper the structural optimization system based on trabecular bone surface adaptation is presented. The basis of the algorithmic formulation was the phenomenon of bone adaptation to mechanical stimulation. Some computation results of trabecular bone functional adaptation as well as of mechanical structures, using the developed system are presented, and compared to other simulation results.

13

Structure optimization system based on the bone surface adaptation phenomenon

Nowak M., Morzyński M.

Computer Assisted Mechanics and Engineering Sciences

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2006

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Vol. 13, No. 4

633-640

EN

In the paper the structure optimization system based on the surface remodeling is presented. The base of algorithm formulation was the trabecular bone surface remodeling phenomenon leading to optimization of the trabecular net in the bone as well as the design with optimal stiffness principle. The closed system including Finite Element mesh generation, decision criterion for structure adaptation and Finite Element Analysis in parallel environment are presented. The issues concerning the use of the tool for the mechanical design are discussed. Some results of computations, using special prepared software are presented.

14

Optimal design of engineering systems using MPI-enabled genetic algorithm

Rajan S. D., Nguyen D. T., Deshpande M. D., Harrell L.

Computer Assisted Mechanics and Engineering Sciences

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2004

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Vol. 11, No. 2-3

155-165

EN

The focus of this paper is on the development and implementation of a genetic algorithm (GA)-based software system using message passing interface (MPI) protocol and library. A customized form of simple GA used in previous research [1-4] is parallelized. This MPI-enabled version is used to find the solution to finite element based design optimization problems. Results show that an almost linear speedup is obtained on homogenous hardware cluster and, with proper reworking of the software, on heterogeneous hardware cluster.

15

Optymalizacja strukturalna i monitorowanie uszkodzeń - pierwszy etap projektu

Palacz M.

Zeszyty Naukowe Katedry Mechaniki Stosowanej / Politechnika Śląska

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2003

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z. 20

333-338

PL

Artykuł stanowi podsumowanie realizacji pierwszej części projektu badawczego, realizowanego przez Instytut Maszyn Przepływowych PAN w Gdańsku, Ośrodek Mechaniki Maszyn, Zakład Statyki i Dynamiki Maszyn Przepływowych ze strony KBN oraz European Aeronautics Defence and Space Company w Monachium ze strony Niemieckiego Ministerstwa Edukacji. Celem projektu jest próba połączenia opracowanych w Polsce modeli skończonych elementów z uszkodzeniami z oprogramowaniem optymalizacyjnym (LAGRANGE) opracowanym w Niemczech.

EN

The paper is a of the first part of recent scientific project held between KBN represented by Institute of Fluid Flow Machinery, Centre of Mechanics of Machines, Statics and Dynamics of Fluid-Flow Machinery Department and German Ministry of Education represented by European Aeronautics Defence and Space Company in Munich, Germany. The aim of the project is to try to connect structural optimisation software (LAGRANGE) developed in EADS with finite elements with cracks developed by Prof. Ostachowicz group in Gdansk.

16

Structural optimization method based on cellular automata simulation

Toyoda T., Kita E.

Computer Assisted Mechanics and Engineering Sciences

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2002

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Vol. 9, No. 2

191-203

EN

This paper describes the topology and the shape optimization scheme of the continuum structures using the cellular automata simulation. The design domain is divided into small square cells. By considering the cells as the elements, the stress analysis of the structure is carried out by finite element method. Then, the design variables are updated according to the local rule and the stress distribution. The rule is defined as the simple relationship between a cell whose design variable is updated and its neighborhood cells. In this paper, we will discuss the formulation to analytically derive the rules from the optimization problems. The special constraint condition named as ``CA-constraint condition'' is introduced first and then, the global optimization problem for the whole structure is divided into the local problem for some neighboring cells. The derived rules are applied to the same numerical example in order to discuss the theoretical validity of the formulation and the feature of the rules.

17

Manufacturing tolerances of truss members' lengths in minimum weight design

Bauer J., Latalski J.

Computer Assisted Mechanics and Engineering Sciences

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2000

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Vol. 7, No. 4

461-469

EN

In most cases a safety of optimal construction may be limited by the violation of stress, buckling or displacement constraints. An unexpected exceed of these constraints may be caused by manufacturing tolerances of structural elements (differences between assumed and obtained dimensions). This requires an incorporation of tolerance problem in optimum design. One may deal with two different tolerances - the first case is when it's related to the members' cross-section variations, whereas the second notion represents the variation of elements' lengths. Considering operation conditions and manufacturing techniques the second case of tolerance seems to be more important. This approach states the problem of minimum weight design of a structure with initial distortions. A standard solution algorithm with the Kuhn-Tucker theorem was used with the adjoint variable method. Necessary optimality conditions have the form of equations and inequalities. The equality constraints were put forward for the average values of design variables l, while tolerances t_j were introduced into inequality equations i.e. the limit values of stresses and displacements were diminished by the positive products of appropriate sensitivities and tolerances. The method was next illustrated by an example of a ten bar bench-mark problem - a typical one for testing algorithms in structural optimization. The idea presented in this paper may be used not only for truss structures but it can be easily extended to other kinds of structures like frames, composites etc.

18

The peculiarities of the structural design and weight characteristics of a "Poliplane" configuration for very large commercial transport

Kolganov A., Pankevich A.

Research Bulletin / Warsaw University of Technology, Institute of Aeronautics and Applied Mechanics

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1999

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nr 9

55-58

EN

At that paper a new aerodynamic scheme "Polyplane" is suggested fog ultra high capacity aircarft and peculiarities of it's load carrying structure are investigated. The calculation schemes and results of finite element calculations are presented. The comparison with the conventional aerodynamic scheme was made and conclusions about the weight efficiency of such a scheme are listed below.

19

Interactive methodology for reliability-based structural design and optimization

Stocki R., Siemaszko R., Kleiber M.

Computer Assisted Mechanics and Engineering Sciences

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1999

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Vol. 6, No. 1

40-62

EN

Recent advances in reliability methods, optimization as well as design sensitivity analysis have resulted in development of computational systems supporting RBDO processes for medium/large structures. For RBDO the efficiency problems are critical and in order to get the optimum design a number of fast approximate methods have been recently proposed. These methods, tested for rather small problems, show acceptable accuracy and speed up computations considerably. However, when applied in the automated way to medium/large scale problems they may cause severe convergence problems or lead to poor local minimum after expensive computations. Instead of an automated optimization procedure, an interactive approach is proposed. Implemented in the POLSAP-RBO system it allows to combine effective interactive design methods with wisual capabilities to efficiently generate optimum design. Benchmark studies of an offshore jacket structure show efficiency of the interactive approach which employs integration, approximation and reduction techniques for maximizing efficiency of RBDO.

20

Axiomatic approach to the multicriteria structural optimization

Pochtman Y. M., Skalozub V. V., Nagornyy D. V.

Computer Assisted Mechanics and Engineering Sciences

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1998

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Vol. 5, nr 3

245-251

EN

The paper present the axiomatic approach for solving the multicriteria optimization of thin-walled structure such as vertical cylindrical reservoirs subject to pitting corrosion. The probabilities of derivation of the compromise optimal project based on maxMin principle are investigated. The analytic dependencies for estimation of the partial criteria weighting coefficients are obtained. The project consists of the optimal thickness of reservoir shell along its height.