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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

Simulation study on the structural optimization of composite insulators based on contaminant deposition

Lv Yukun, Chen Zeze, Wang Qian, Lu Yao, Li Xiaojing

Archives of Electrical Engineering

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2023

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Vol. 72, nr 4

1089--1105

EN

Optimizing the aerodynamic structure of composite insulators can guarantee the safe operation of power systems. In this study, we construct a simulation model for composite insulator contaminant deposition using the COMSOL simulation software, and the rationality of the simulation model and method is verified through wind tunnel experiments. Taking the FXBW4-110/100 composite insulator as an example, we adopt a progressive optimization plan to explore the impacts of shed spacing s, and shed inclination angles α and β on its contaminant deposition characteristics under DC and AC voltages. Based on the numerical simulation results, we analyze the antifouling performance of insulators before and after structural optimization. The results indicate the following: 1) The contaminant deposition of the insulator under AC and DC voltages is negatively correlated with the shed spacing s, but positively correlated with the lower inclination angle β. 2) Under AC voltages, the contaminant deposition of the insulator increases with the upper inclination angle α, while under DC voltages, the contaminant deposition shows an uptrend first, then a downtrend and then an uptrend again with the increase of the upper inclination angle α. 3) Compared with the original model, the AC-optimized model ( α = 6°, β = 2° and s = 98 mm) with a larger shed spacing s, and smaller shed inclination angles α and β showed superior antifouling performance at wind speeds of no less than 2 m/s, and under the typical conditions ( v = 2.5 m/s, d = 20 μm, and ρ = 2 200 kg/m 3), its contaminant deposition is 15% less than that of the original model ( α = 10°, β = 2° and s = 80 mm).

3

Preliminary optimization technique in the design of steel girders according to Eurocode 3

Szeptyński Paweł, Mikulski Leszek

Archives of Civil Engineering

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2023

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Vol. 69, nr 1

71--89

EN

The problem of optimal design of a steel plated girder according to the Eurocode 3 is considered. Code regulations admit the Finite Element Analysis (FEA) in designing plated structures with variable cross-sections. A technique of determining an approximate solution to the optimization problem is presented. It is determined a solution of a control theory optimization task, in which Eurocode requirements regarding the Ultimate Limit State (bearing capacity, local and global stability) as well as Serviceability Limit State (flexural rigidity) are used as appropriate inequality constraints. Static analysis is performed within the framework of linear elasticity and Bernoulli-Euler beam theory making an account for second-order effects due to prescribed imperfections. Obtained solutions, after regularization, may be used for direct verification with the use of FEA or as the first guess for iterative topology optimization algorithms. Code requirements governing the determination of optimal shape are visualized in the constraint activity diagram, which is a proposed tool for analysis of optimization process.

PL

Rozważany jest problem optymalnego projektowania blachownicy stalowej zgodnie z Eurokodem 3. Zapisy normowe dopuszczają stosowanie Metody Elementów Skończonych (MES) w projektowaniu blachownic o zmiennym przekroju poprzecznym. Przedstawiono metodę wyznaczania przybliżonego rozwiązania zagadnienia optymalizacji. Jest ono wyznaczane jako rozwiązanie problemu optymalizacyjnego teorii sterowania, w którym wymagania Eurokodu dotyczące Stanu Granicznego Nośności (nośność, lokalna i globalna stateczność) i Stanu Granicznego Użytkowalności (sztywność giętna) wykorzystane są jako ograniczenia nierównościowe. Analiza statyczna przeprowadzona jest w ramach liniowej teorii sprężystości dla modelu belki Bernoulliego - Eulera z uwzględnieniem efektów drugiego rzędu z uwagi na zadane imperfekcje. Uzyskane rozwiązania, po stosownych modyfikacjach, mogą podlegać weryfikacji z wykorzystaniem MES lub mogą zostać wykorzystane jako pierwsze przybliżenie w iteracyjnych algorytmach optymalizacji topologicznej. Wymagania normowe rządzące wyznaczaniem optymalnego kształtu zostały zwizualizowane na schemacie aktywności ograniczeń, który proponowany jest jako narzędzie analizy procesu optymalizacji.

4

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.

5

Optimum design of elastic moduli for the multiple load problems

Lewiński T.

Archives of Mechanics

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2021

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Vol. 73, nr 1

27--66

EN

The paper deals with minimization of the weighted average of compliances of structures, made of an elastic material of spatially varying elasticity moduli, subjected to n load variants acting non-simultaneously. The trace of the Hooke tensor is assumed as the unit cost of the design. Three versions of the free material design are discussed: designing the moduli of arbitrary anisotropy (AMD), designing the moduli of an isotropic material (IMD), designing of Young’s modulus for a fixed Poisson ratio (YMD). The problem is in all cases reduced to the Linear Constrained Problem (LCP) of Bouchitté and Fragalà consisting of two mutually dual problems: stress based and strain based, the former one being characterized by the integrand of linear growth depending on the trial statically admissible stresses. The paper shows equivalence of the stress fields solving the (LCP) problem and those appearing in the optimal body subjected to subsequent load cases.

6

Michell structures within L-shaped domains

Bołbotowski Karol, Lewiński Tomasz, Sokół Tomasz

Computer Assisted Methods in Engineering and Science

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2020

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Vol. 27, no. 2-3

185--204

EN

By recalling the main mathematical results concerning the theory of Michell structures,the present paper puts forward an interpretation of the selected numerical methods forconstructing their approximants, that is, trusses with a large number of nodes. The ef-ficiency of one of these methods: the ground structure method in its adaptive version isshown in the context of the L-shaped design domain problem. A large family of highlyaccurate truss approximants corresponding to the point loads acting at selected verticesis constructed and discussed.

7

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.

8

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.

9

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 3

731--753

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.

10

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.

11

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.

12

Preliminary dimensioning of crushed beams using macro elements and optimization methods

Krzywobłocki M.

Zeszyty Naukowe Instytutu Pojazdów / Politechnika Warszawska

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2016

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z. 4/108

25--31

EN

The article presents the modeling of large deformations of thin walled structures combined with an optimization algorithm. Such components are commonly used in the car industry to absorb the shock energy and to protect the driver and the passengers. The objective is to determine cross sectional dimensions of prismatic beams which fulfill specific requirements. The beam examples with rectangular and hexagonal cross sections are investigated numerically. The Visual Crash Studio software based on Macro Element Method (MEM) is used to calculate crashworthy parameters of the beam models. The Monte Carlo search algorithm developed in C# programming language returns the optimization results.

PL

W artykule przedstawiono modelowanie dużych deformacji konstrukcji cienkościennych w połączeniu z algorytmem optymalizacyjnym. Elementy cienkościenne są powszechnie stosowane w przemyśle samochodowym, jako integralna część budowy nadwozia i służą do absorbcji energii oraz ochrony kierowcy i pasażerów w przypadku zderzenia. Celem pracy jest ustalenie wymiarów przekrojów belek pryzmatycznych, spełniających określone wymagania projektowe. W przykładach numerycznych badane się belki o przekrojach prostokątnych i sześciokątnych. Do wyznaczenia parametrów pozwalających na ocenę energochłonności zdefiniowanego modelu wykorzystano oprogramowanie Visual Crash Studio(VCS), którego działanie bazuje na metodzie Makro Elementów. Algorytm Monte Carlo opracowany w języku programowania C# przetwarza wyniki obliczeń VCS oraz zwraca wyniki optymalizacji.

13

Implementation of logic flow in planning and production control

Ulewicz R., Jelonek D., Mazur M.

Management and Production Engineering Review

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2016

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Vol. 7, No. 1

89--94

EN

The article presents the results of analysis, the use of continuous flow of logic at the stage of production planning and control of the company producing furniture. The concept of continuous flow tends to regulate the flow of materials in a manner that provides the shortest flow path without unnecessary activities (Muda is a Japanese word meaning waste), a constant takt and defined throughput at constant resource requirements for the so-called transfer of material through the whole process. In the study Glenday’d sieve method was used to identify the correct area, which requires the value stream mapping, and areas called excessive complexity, which do not provide added value. The use of Glenday’s sieve method made it possible to identify areas in which it must be improve production capacity.

14

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.

15

Dynamic analysis and optimization of a bionic flapping-wing aircraft

Jin X., Zhou X., Tian P., Zhang L., Nie Z.

Engineering Transactions

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2016

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Vol. 64, iss. 2

181--196

EN

This research has been conducted for the purpose of developing bionic flapping-wing aircraft. In this paper, wings are regarded as flexible, and the response issues of wings under certain excitation functions are investigated. The research is based on preliminary studies about bionic flapping wings and aims to provide data references to aid the selection of electrical actuators and the design of driving mechanisms for bionic flapping-wing aircraft at a later stage. The dynamic analysis shows that the response functions adapt well to the flapping movements of the wings. However, there are mutational situations in the wing structure transformation which are bad for structural stability, and cause there to be too little lift force. Under such circumstances, the minimum norm of low-order vibration mode difference values is used as the optimization principle to conduct the structural optimization. The optimization results and the wing flutter test both show that the optimized wings can better avoid structural mutations and their response functions can also better meet the design requirements.

16

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.

17

Dynamic programming approach to structural optimization problem - numerical algorithm

Fulmański P., Nowakowski A., Pustelnik J.

Opuscula Mathematica

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2014

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Vol. 34, no. 4

699--724

EN

In this paper a new shape optimization algorithm is presented. As a model application we consider state problems related to fluid mechanics, namely the Navier-Stokes equations for viscous incompressible fluids. The general approach to the problem is described. Next, transformations to classical optimal control problems are presented. Then, the dynamic programming approach is used and sufficient conditions for the shape optimization problem are given. A new numerical method to find the approximate value function is developed.

18

Solving of linear programming by method of structural optimization

Karganov S. A.

Zeszyty Naukowe / Akademia Morska w Szczecinie

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2013

|

nr 34 (106)

48--58

EN

The paper lists the problems hindering the use in business practices of the results of solving direct and inverse problems in linear programming. It is shown that overcoming these obstacles lies in the way of using of developed by the author and described in this paper method of structural optimization and algorithms for its implementation. Here are some examples of solutions by the method of structural optimization of production planning problems.

19

Multi - material design optimization of a bus body structure

Korta J., Uhl T.

Journal of KONES

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2013

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Vol. 20, No. 1

139--146

EN

In the recent years the safety and eco-friendliness have gained much of attention of the automotive stakeholders. These two characteristics are especially important in the case of mass transportation vehicles, such as buses or coaches, which are in continues use for long periods of time, covering significant distances. In such situations, the economical aspects play major role for the transportation companies which try to minimize operational costs of their fleet, by choosing vehicles with reduced fuel consumption. In order to obtain improvements in all the mentioned areas and hence to strengthen their position on the market, bus manufacturers have recently turned their attention to multimaterial design strategies. Structures built in that manner consist not only of regular steel parts, but contain also a mix of components made from various lightweight materials like aluminum alloys or composites, which allow for significant reduction in vehicle curb weight. However, due to the differences in mechanical characteristics which are especially evident in the case of laminates, the material substitution is not a straightforward task. In order to find the material distribution pattern that meets all the requirements, a great number of prototypic numerical models must be prepared and tested. To ease the search for the final solution, optimization techniques can be applied into the design process, allowing for automatic design modifications and assessment of the obtained results. The paper presents an attempt of enhancing the operational characteristics of a bus body structure with simultaneous reduction in the structural weight. In order to find the optimal component configuration, a multimaterial optimization was employed and supplemented by sensitivity and robustness analyses. Such a technique helps to discriminate the over-optimized solutions that are often pointed out as the most desirable by the optimization algorithms which neglect the uncertainties of the analysed system.

20

Topology optimization in structural mechanics

Lewiński T., Czarnecki S., Dzierżanowski G., Sokół T.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2013

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Vol. 61, nr 1

23-37

EN

Optimization of structural topology, called briefly: topology optimization, is a relatively new branch of structural optimization. Its aim is to create optimal structures, instead of correcting the dimensions or changing the shapes of initial designs. For being able to create the structure, one should have a possibility to handle the members of zero stiffness or admit the material of singular constitutive properties, i.e. void. In the present paper, four fundamental problems of topology optimization are discussed: Michell’s structures, two-material layout problem in light of the relaxation by homogenization theory, optimal shape design and the free material design. Their features are disclosed by presenting results for selected problems concerning the same feasible domain, boundary conditions and applied loading. This discussion provides a short introduction into current topics of topology optimization.