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  Subjects -> ENGINEERING (Total: 2265 journals)
    - CHEMICAL ENGINEERING (188 journals)
    - CIVIL ENGINEERING (179 journals)
    - ELECTRICAL ENGINEERING (99 journals)
    - ENGINEERING (1210 journals)
    - ENGINEERING MECHANICS AND MATERIALS (384 journals)
    - HYDRAULIC ENGINEERING (55 journals)
    - INDUSTRIAL ENGINEERING (60 journals)
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CIVIL ENGINEERING (179 journals)                     

Showing 1 - 0 of 0 Journals sorted alphabetically
ACI Structural Journal     Full-text available via subscription   (Followers: 8)
Acta Polytechnica : Journal of Advanced Engineering     Open Access  
Acta Structilia : Journal for the Physical and Development Sciences     Open Access   (Followers: 1)
Advances in Civil Engineering     Open Access   (Followers: 27)
Advances in Structural Engineering     Full-text available via subscription   (Followers: 17)
Ambiente Construído     Open Access   (Followers: 1)
American Journal of Civil Engineering and Architecture     Open Access   (Followers: 22)
Architectural Engineering     Open Access   (Followers: 4)
Archives of Civil Engineering     Open Access   (Followers: 6)
Archives of Hydro-Engineering and Environmental Mechanics     Open Access  
ATBU Journal of Environmental Technology     Open Access   (Followers: 1)
Australian Journal of Structural Engineering     Full-text available via subscription   (Followers: 4)
Baltic Journal of Road and Bridge Engineering     Full-text available via subscription   (Followers: 1)
BER : Building and Construction : Full Survey     Full-text available via subscription   (Followers: 8)
BER : Building Contractors' Survey     Full-text available via subscription   (Followers: 4)
BER : Building Sub-Contractors' Survey     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Building and Construction : An Executive Summary     Full-text available via subscription   (Followers: 4)
Berkeley Planning Journal     Open Access   (Followers: 5)
Bioinspired Materials     Open Access   (Followers: 2)
Bridge Structures : Assessment, Design and Construction     Hybrid Journal   (Followers: 13)
Building and Environment     Hybrid Journal   (Followers: 12)
Building Women     Full-text available via subscription  
Built Environment Project and Asset Management     Hybrid Journal   (Followers: 14)
Bulletin of Pridniprovsk State Academy of Civil Engineering and Architecture     Open Access   (Followers: 4)
Canadian Journal of Civil Engineering     Full-text available via subscription   (Followers: 9)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 6)
Case Studies in Nondestructive Testing and Evaluation     Open Access   (Followers: 3)
Case Studies in Structural Engineering     Open Access   (Followers: 3)
Cement and Concrete Composites     Hybrid Journal   (Followers: 13)
Challenge Journal of Structural Mechanics     Open Access   (Followers: 4)
Change Over Time     Full-text available via subscription   (Followers: 2)
Civil and Environmental Engineering     Open Access   (Followers: 6)
Civil And Environmental Engineering Reports     Open Access   (Followers: 4)
Civil and Environmental Research     Open Access   (Followers: 15)
Civil Engineering = Siviele Ingenieurswese     Full-text available via subscription   (Followers: 4)
Civil Engineering and Architecture     Open Access   (Followers: 8)
Civil Engineering and Environmental Systems     Hybrid Journal   (Followers: 2)
Civil Engineering and Technology     Open Access   (Followers: 5)
Civil Engineering Dimension     Open Access   (Followers: 5)
Cohesion and Structure     Full-text available via subscription   (Followers: 2)
Composite Structures     Hybrid Journal   (Followers: 206)
Computer-aided Civil and Infrastructure Engineering     Hybrid Journal   (Followers: 8)
Computers & Structures     Hybrid Journal   (Followers: 28)
Concrete Research Letters     Open Access   (Followers: 2)
Construction Economics and Building     Open Access   (Followers: 1)
Construction Engineering     Open Access   (Followers: 5)
Construction Management and Economics     Hybrid Journal   (Followers: 18)
Construction Science     Open Access   (Followers: 1)
Constructive Approximation     Hybrid Journal  
Curved and Layered Structures     Open Access   (Followers: 1)
DFI Journal : The Journal of the Deep Foundations Institute     Hybrid Journal   (Followers: 1)
Earthquake Engineering and Structural Dynamics     Hybrid Journal   (Followers: 14)
Enfoque UTE     Open Access   (Followers: 1)
Engineering Project Organization Journal     Hybrid Journal   (Followers: 5)
Engineering Structures     Hybrid Journal   (Followers: 11)
Engineering Structures and Technologies     Hybrid Journal   (Followers: 1)
Engineering, Construction and Architectural Management     Hybrid Journal   (Followers: 12)
Environmental Geotechnics     Open Access   (Followers: 3)
European Journal of Environmental and Civil Engineering     Hybrid Journal   (Followers: 6)
Fatigue & Fracture of Engineering Materials and Structures     Hybrid Journal   (Followers: 13)
Frattura ed Integrità Strutturale : Fracture and Structural Integrity     Open Access  
Frontiers in Built Environment     Open Access  
Frontiers of Structural and Civil Engineering     Hybrid Journal   (Followers: 5)
Geomaterials     Open Access   (Followers: 1)
Geosystem Engineering     Hybrid Journal   (Followers: 1)
Geotechnik     Hybrid Journal   (Followers: 1)
Géotechnique Letters     Hybrid Journal   (Followers: 4)
HBRC Journal     Open Access   (Followers: 1)
Hormigón y Acero     Full-text available via subscription  
HVAC&R Research     Hybrid Journal  
Indoor and Built Environment     Hybrid Journal   (Followers: 1)
Infrastructure Asset Management     Hybrid Journal   (Followers: 1)
Ingenio Magno     Open Access  
Insight - Non-Destructive Testing and Condition Monitoring     Full-text available via subscription   (Followers: 15)
International Journal for Service Learning in Engineering     Open Access  
International Journal of 3-D Information Modeling     Full-text available via subscription   (Followers: 2)
International Journal of Advanced Structural Engineering     Open Access   (Followers: 9)
International Journal of Concrete Structures and Materials     Open Access   (Followers: 7)
International Journal of Condition Monitoring     Full-text available via subscription   (Followers: 1)
International Journal of Construction Engineering and Management     Open Access   (Followers: 4)
International Journal of Geo-Engineering     Open Access  
International Journal of Geosynthetics and Ground Engineering     Full-text available via subscription   (Followers: 2)
International Journal of Masonry Research and Innovation     Hybrid Journal  
International Journal of Pavement Research and Technology     Open Access   (Followers: 2)
International Journal of Protective Structures     Full-text available via subscription   (Followers: 4)
International Journal of Steel Structures     Hybrid Journal   (Followers: 2)
International Journal of Structural Engineering     Hybrid Journal   (Followers: 7)
International Journal of Structural Integrity     Hybrid Journal  
International Journal of Structural Stability and Dynamics     Hybrid Journal   (Followers: 5)
International Journal of Sustainable Built Environment     Open Access   (Followers: 3)
International Journal of Sustainable Construction Engineering and Technology     Open Access   (Followers: 7)
International Journal on Pavement Engineering & Asphalt Technology     Open Access   (Followers: 4)
Journal of Bridge Engineering     Full-text available via subscription   (Followers: 15)
Journal of Building Engineering     Hybrid Journal  
Journal of Building Materials and Structures     Open Access   (Followers: 1)
Journal of Building Performance Simulation     Hybrid Journal   (Followers: 5)
Journal of Civil Engineering and Construction Technology     Open Access   (Followers: 6)
Journal of Civil Engineering and Management     Hybrid Journal   (Followers: 6)
Journal of Civil Engineering and Science     Open Access   (Followers: 6)
Journal of Civil Engineering Research     Open Access   (Followers: 5)
Journal of Civil Society     Hybrid Journal   (Followers: 3)
Journal of Civil Structural Health Monitoring     Hybrid Journal   (Followers: 3)
Journal of Composites     Open Access   (Followers: 72)
Journal of Composites for Construction     Full-text available via subscription   (Followers: 12)
Journal of Computing in Civil Engineering     Full-text available via subscription   (Followers: 21)
Journal of Construction Engineering     Open Access   (Followers: 4)
Journal of Construction Engineering and Management     Full-text available via subscription   (Followers: 19)
Journal of Construction Engineering, Technology & Management     Full-text available via subscription   (Followers: 2)
Journal of Constructional Steel Research     Hybrid Journal   (Followers: 6)
Journal of Earth Sciences and Geotechnical Engineering     Open Access   (Followers: 2)
Journal of Fluids and Structures     Hybrid Journal   (Followers: 5)
Journal of Frontiers in Construction Engineering     Open Access   (Followers: 3)
Journal of Green Building     Full-text available via subscription   (Followers: 10)
Journal of Highway and Transportation Research and Development (English Edition)     Full-text available via subscription   (Followers: 10)
Journal of Infrastructure Systems     Full-text available via subscription   (Followers: 19)
Journal of Legal Affairs and Dispute Resolution in Engineering and Construction     Full-text available via subscription   (Followers: 4)
Journal of Marine Science and Engineering     Open Access   (Followers: 1)
Journal of Materials in Civil Engineering     Full-text available via subscription   (Followers: 10)
Journal of Multifunctional Composites     Full-text available via subscription   (Followers: 3)
Journal of Nondestructive Evaluation     Hybrid Journal   (Followers: 7)
Journal of Offshore Structure and Technology     Full-text available via subscription  
Journal of Performance of Constructed Facilities     Full-text available via subscription   (Followers: 4)
Journal of Pipeline Systems Engineering and Practice     Full-text available via subscription   (Followers: 7)
Journal of Rehabilitation in Civil Engineering     Open Access  
Journal of Solid Waste Technology and Management     Full-text available via subscription  
Journal of Structural Engineering     Full-text available via subscription   (Followers: 36)
Journal of Structural Fire Engineering     Full-text available via subscription   (Followers: 6)
Journal of Structures     Open Access   (Followers: 2)
Journal of Sustainable Architecture and Civil Engineering     Open Access  
Journal of Sustainable Design and Applied Research in Innovative Engineering of the Built Environment     Open Access   (Followers: 1)
Journal of the South African Institution of Civil Engineering     Open Access   (Followers: 4)
KSCE Journal of Civil Engineering     Hybrid Journal   (Followers: 1)
Latin American Journal of Solids and Structures     Open Access   (Followers: 1)
Materiales de Construcción     Open Access  
Mathematical Modelling in Civil Engineering     Open Access   (Followers: 3)
Nondestructive Testing And Evaluation     Hybrid Journal   (Followers: 11)
Obras y Proyectos     Open Access   (Followers: 1)
Open Journal of Civil Engineering     Open Access   (Followers: 3)
Photonics and Nanostructures - Fundamentals and Applications     Hybrid Journal   (Followers: 2)
Practice Periodical on Structural Design and Construction     Full-text available via subscription   (Followers: 4)
Proceedings of the Institution of Civil Engineers - Bridge Engineering     Hybrid Journal   (Followers: 6)
Proceedings of the Institution of Civil Engineers - Civil Engineering     Hybrid Journal   (Followers: 11)
Proceedings of the Institution of Civil Engineers - Management, Procurement and Law     Hybrid Journal   (Followers: 6)
Proceedings of the Institution of Civil Engineers - Municipal Engineer     Hybrid Journal   (Followers: 3)
Proceedings of the Institution of Civil Engineers - Structures and Buildings     Hybrid Journal   (Followers: 3)
Random Structures and Algorithms     Hybrid Journal   (Followers: 3)
Recent Trends In Civil Engineering & Technology     Full-text available via subscription   (Followers: 2)
Research in Nondestructive Evaluation     Hybrid Journal   (Followers: 4)
Revista IBRACON de Estruturas e Materiais     Open Access   (Followers: 1)
Road Materials and Pavement Design     Hybrid Journal   (Followers: 7)
Russian Journal of Nondestructive Testing     Hybrid Journal   (Followers: 2)
Science and Engineering of Composite Materials     Hybrid Journal   (Followers: 54)
Selected Scientific Papers - Journal of Civil Engineering     Open Access   (Followers: 3)
Slovak Journal of Civil Engineering     Open Access   (Followers: 2)
Soils and foundations     Full-text available via subscription   (Followers: 1)
Steel Construction - Design and Research     Hybrid Journal   (Followers: 1)
Structural and Multidisciplinary Optimization     Hybrid Journal   (Followers: 8)
Structural Concrete     Hybrid Journal   (Followers: 9)
Structural Control and Health Monitoring     Hybrid Journal   (Followers: 6)
Structural Engineering International     Full-text available via subscription   (Followers: 9)
Structural Safety     Hybrid Journal   (Followers: 7)
Structural Survey     Hybrid Journal  
Structure     Full-text available via subscription   (Followers: 24)
Structure and Infrastructure Engineering: Maintenance, Management, Life-Cycle Design and Performance     Hybrid Journal   (Followers: 9)
Structures     Hybrid Journal  
Study of Civil Engineering and Architecture     Open Access   (Followers: 7)
Superlattices and Microstructures     Hybrid Journal   (Followers: 2)
Surface Innovations     Hybrid Journal  
Technical Report Civil and Architectural Engineering     Open Access  
Teknik     Open Access  
The IES Journal Part A: Civil & Structural Engineering     Hybrid Journal   (Followers: 5)
The Structural Design of Tall and Special Buildings     Hybrid Journal   (Followers: 5)
Thin Films and Nanostructures     Full-text available via subscription   (Followers: 1)
Thin-Walled Structures     Hybrid Journal   (Followers: 2)
Transactions of the VŠB - Technical University of Ostrava. Construction Series     Open Access   (Followers: 1)
Transportation Geotechnics     Full-text available via subscription   (Followers: 1)
Transportation Infrastructure Geotechnology     Hybrid Journal   (Followers: 8)
Water Science & Technology     Partially Free   (Followers: 21)
Water Science and Technology : Water Supply     Partially Free   (Followers: 21)

           

Journal Cover Structural and Multidisciplinary Optimization
  [SJR: 1.825]   [H-I: 61]   [8 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1615-1488 - ISSN (Online) 1615-147X
   Published by Springer-Verlag Homepage  [2335 journals]
  • Topological shape optimization of multifunctional tissue engineering
           scaffolds with level set method
    • Abstract: Abstract A tissue engineering scaffold provides a proper environment to support physiological loads, and enhance cell migration and delivery for re-modeling of regenerating tissue. Hence, in the design of scaffolds, it is required to control the scaffold architecture with mechanical and mass transport properties simultaneously. In this paper, a level set-based topology optimization method will be developed to systematically generate three dimensional (3D) microstructures for tissue engineering scaffolds, with the prescribed properties for mechanical stiffness, fluid porosity and permeability. To create the internal architecture for scaffolds with desired properties, the numerical homogenization method will be used to evaluate the effective properties of the microstructure for building the periodic composite media, and a parametric level set method will be introduced to find the optimized shape and topology of the microstructure. Several numerical examples are used to demonstrate the effectiveness of the proposed method in achieving scaffolds with desired multifunctional properties, within the numerically estimated cross-property bounds between the effective bulk modulus and permeability under different porosities.
      PubDate: 2016-08-01
       
  • A first order approach for worst-case shape optimization of the compliance
           for a mixture in the low contrast regime
    • Abstract: Abstract The purpose of this article is to propose a deterministic method for optimizing a structure considering its worst possible behaviour when a small uncertainty exists over its Lamé parameters. The idea is to take advantage of the small parameter to derive an asymptotic expansion of the displacement and of the compliance with respect to the contrast in Lamé coefficients. We are then able to compute the worst case design as post-treatment of the computation of the displacement field for the nominal parameters. The domain evolution resulting from the optimization is performed here using the level set method. The computational cost of our method remains of the same order as the cost of the optimization for a homogeneous material.
      PubDate: 2016-08-01
       
  • Mixed-integer second-order cone programming for global optimization of
           compliance of frame structure with discrete design variables
    • Abstract: Abstract Frame structures are extensively used in mechanical, civil, and aerospace engineering. Besides generating reasonable designs of frame structures themselves, frame topology optimization may serve as a tool providing us with conceptual designs of diverse engineering structures. Due to its nonconvexity, however, most of existing approaches to frame topology optimization are local optimization methods based on nonlinear programming with continuous design variables or (meta)heuristics allowing some discrete design variables. Presented in this paper is a new global optimization approach to the frame topology optimization with discrete design variables. It is shown that the compliance minimization problem with predetermined candidate cross-sections can be formulated as a mixed-integer second-order cone programming problem. The global optimal solution is then computed with an existing solver based on a branch-and-cut algorithm. Numerical experiments are performed to examine computational efficiency of the proposed approach.
      PubDate: 2016-08-01
       
  • A general RBDO decoupling approach for different reliability analysis
           methods
    • Abstract: Abstract There are available in the literature several papers on the development of methods to decouple the reliability analysis and the structural optimization to solve RBDO problems. Most of them focused on strategies that employ the First Order Reliability Method (FORM) to approximate the reliability constraints. Despite of all these developments, one limitation prevailed: the lack of accuracy in the approximation of the reliability constraints due to the use of FORM. Thus, in this paper, a novel approach for RBDO is presented in order to overcome such a limitation. In this approach, we use the concept of shifting vectors, originally developed in the context of the Sequential Optimization and Reliability Assessment (SORA). However, the shifting vectors are found and updated based on a novel strategy. The resulting framework is able to use any technique for the reliability analysis stage, such as Monte Carlo simulation, second order reliability methods, stochastic polynomials, among others. Thus, the proposed approach overcomes the aforementioned limitation of most of RBDO decoupling techniques, which required the use of FORM for reliability analysis. Several examples are analyzed in order to show the effectiveness of the methodology. Focus is given on examples that are poorly solved or even cannot be tackled by FORM based approaches, such as highly nonlinear limit state functions comprised by a maximum operator or problems with discrete random variables. It should be remarked that the proposed approach was not developed to be more computationally efficient than RBDO decoupling strategies based FORM, but to allow the utilization of any, including more accurate, reliability analysis method.
      PubDate: 2016-08-01
       
  • Design complexity control in truss optimization
    • Abstract: Abstract Truss optimization based on the ground structure approach often leads to designs that are too complex for practical purposes. In this paper we present an approach for design complexity control in truss optimization. The approach is based on design complexity measures related to the number of bars (similar to Asadpoure et al. Struct Multidisc Optim 51(2):385–396 2015) and a novel complexity measure related to the number of nodes of the structure. Both complexity measures are continuously differentiable and thus can be used together with gradient based optimization algorithms. The numerical examples show that the proposed approach is able to reduce design complexity, leading to solutions that are more fit for engineering practice. Besides, the examples also indicate that in some cases it is possible to significantly reduce design complexity with little impact on structural performance. Since the complexity measures are non convex, a global gradient based optimization algorithm is employed. Finally, a detailed comparison to a classical approach is presented.
      PubDate: 2016-08-01
       
  • Cost optimization of structures using a genetic algorithm with Eugenic
           Evolutionary theory
    • Abstract: Abstract This paper illustrates the cost optimization of steel frame structures by mean of genetic algorithm developed from the Eugenics Evolutionary theory. The aim is to obtain a final structure with a minimum cost. To this end, a modified multiple objective function has been defined. This considers cost as the result of a summary where elements like welds, simple connections, or the number of structural elements, have an influence on the final result. According to the Eugenics Evolutionary theory, a new selection operator has been developed in a way that leads to all members of the population being able to have descendants and avoids the loss of any kind of genetic material. In addition, the penalization coefficients have been optimised and the effect of parameter setting has been investigated, to achieve convergence faster through penalising the most expensive structures and looking for the optimum range of parameters’ value. The result is a robust genetic algorithm which, compared with others, achieves better optimum individuals and does not stop at local minima. Finally, two different two-dimensional truss frames have been optimized and the results have been compared with those obtained using different methods of selection like elitism, steady-state replacement, roulette wheel, and tournament selection.
      PubDate: 2016-08-01
       
  • Free-form optimization method for buckling of shell structures under
           out-of-plane and in-plane shape variations
    • Abstract: Abstract In the present work, in order to tackle the linear elastic buckling problem, we develop a shape optimization process based on a free-form optimization method to optimize a shell structure under out-of-plane and in-plane shape variations. The free-form optimization method is a node-based method in which mesh regularity can be maintained and shape design parameterization is not required. It has the advantages of sufficient efficiency for treating large-scale problems and the ability to realize a smooth shape. The buckling coefficient in buckling mode 1 is set as the objective function in the shape optimization problem. We consider repeated eigenvalues and volume constraint for the whole optimization process. Three numerical examples are presented in this work to illustrate the shape optimization algorithm and to show that it can increase the buckling strength substantially, especially under shape variation in the out-of-plane direction.
      PubDate: 2016-08-01
       
  • Matlab codes of Subset Simulation for reliability analysis and structural
           optimization
    • Abstract: Abstract This paper presents two efficient and compact Matlab codes of Subset Simulation for reliability analysis and structural optimization. The codes for reliability analysis and structural optimization comprise of the direct Monte Carlo and Markov Chain Monte Carlo. The theoretical and numerical elements of Subset Simulation are briefly presented in this paper, as well as the detailed instructions to implement the standard codes for solving reliability analysis and structural optimization problems. The paper also discusses simple extensions of argument check, post-processing, alternative stop criterion and constraint-handling. Four examples are presented to demonstrate these codes, two for reliability analysis and two for structural optimization. This paper will be helpful for the students and newcomers both in reliability analysis and structural optimization to understand and use Subset Simulation. The complete codes are included in Appendixes 1 and 2, and they can be downloaded from https://sites.google.com/site/rasosubsim/.
      PubDate: 2016-08-01
       
  • Finite element analysis and topology optimization of a 12000KN fine
           blanking press frame
    • Abstract: Abstract Fine blanking press frame is one of the core components of the fine blanking press. Good performance of the frame is of great importance to ensure blanking precision. Simultaneously, lightweight of the frame would decrease the total press weight, and reduce the consumption of manufacturing and transportation. In this paper, the topology optimization technology was used to optimize a 12000KN fine blanking press frame. Firstly, a finite element model was established to analyze the original 12000KN fine blanking press frame. The proper way of finite element modelling was determined by an experiment. Then, an optimization problem was formulated using Solid Isotropic Microstructures with Penalization (SIMP) method. After that, a testing topology optimization was conducted, whose result revealed some complex, non-manufacturable design features. To cope with these exposed issues and obtain a result with clearer configuration and better manufacturability, a two-stage optimization procedure was proposed, in which manufacturing constraints played an important role. Ultimately, an optimized CAD model for the frame was constructed, and finite element analysis showed that 13.66 % volume reduction was achieved while the performance slightly increased compared with the original frame.
      PubDate: 2016-08-01
       
  • Quantifying tradeoffs to reduce the dimensionality of complex design
           optimization problems and expedite trade space exploration
    • Abstract: Abstract Multi-objective optimization is increasingly being employed to solve complex design problems. However, multi-objective optimization problems might be formulated with extraneous objective functions that could be eliminated without affecting the final solution. Furthermore, as the number of objectives increases, the effort required to visualize and explore the resulting solution set, herein referred to as the trade space, increases. Although visual analytic techniques exist to facilitate analytical reasoning for exploring a high-dimensional trade space through graphical interfaces, existing techniques often rely upon exhaustive two-dimensional representations to identify all tradeoffs. Yet, the knowledge of the tradeoffs among competing objectives is important for decision-making because it fosters learning from the trade space and hence aids preference formation. In this paper, an index to quantify the tradeoff between any two objectives from multi-objective optimization is presented and incorporated into a visual analytic technique that can be used as a tool for reducing the dimensionality of the problem formulation. The tradeoff index reveals the conflicting and correlated objectives; hence, it can be used to expedite trade space exploration by focusing cognitive effort only on those objectives that have tradeoff. The utility and efficiency of the proposed technique is illustrated through application to a Pareto approximate solution set from a benchmark optimization problem with eight objectives. The results of this exercise are compared to the solutions obtained using other existing visual analytic techniques found in the literature.
      PubDate: 2016-08-01
       
  • On optimization of interference fit assembly
    • Abstract: Abstract Assembly of shaft and hub by an interference fit is a classical connection with known advantages and disadvantages. The advantage being the level of possible torque transfer while the disadvantage is a possible fretting fatigue failure at the points of stress concentration. To improve the assembly the present paper discusses different optimized designs that improve the contact pressure distribution. The pressure distribution in the contact is the source responsible for the fatigue failure. The distribution can be improved by design modification done directly on the contacting surfaces which however requires a very high production precision. Alternatively it is shown, how hub side shape optimization can improve the pressure distribution significantly. The latter design change has no influence on the remaining shaft-hub design i.e. the attachment of other parts. The analysis is performed either by a traditional contact analysis, or by a super element contact analysis where no iterations are needed for the contact evaluation.
      PubDate: 2016-08-01
       
  • Can damping be ignored in transient structural dynamic optimization?
    • Abstract: Abstract In this note, we show that for a undamped structure, the solution of transient response sensitivity contains resonant terms that grow with time without bounds. Thus damping cannot be ignored in transient structural dynamic optimization.
      PubDate: 2016-08-01
       
  • Topological derivatives applied to fluid flow channel design optimization
           problems
    • Abstract: Abstract Topology optimization methods application for viscous flow problems is currently an active area of research. A general approach to deal with shape and topology optimization design is based on the topological derivative. This relatively new concept represents the first term of the asymptotic expansion of a given shape functional with respect to the small parameter which measures the size of singular domain perturbations, such as holes and inclusions. In previous topological derivative-based formulations for viscous fluid flow problems, the topology is obtained by nucleating and removing holes in the fluid domain which creates numerical difficulties to deal with the boundary conditions for these holes. Thus, we propose a topological derivative formulation for fluid flow channel design based on the concept of traditional topology optimization formulations in which solid or fluid material is distributed at each point of the domain to optimize the cost function subjected to some constraints. By using this idea, the problem of dealing with the hole boundary conditions during the optimization process is solved because the asymptotic expansion is performed with respect to the nucleation of inclusions – which mimic solid or fluid phases – instead of inserting or removing holes in the fluid domain, which allows for working in a fixed computational domain. To evaluate the formulation, an optimization problem which consists in minimizing the energy dissipation in fluid flow channels is implemented. Results from considering Stokes and Navier-Stokes are presented and compared, as well as two- (2D) and three-dimensional (3D) designs. The topologies can be obtained in a few iterations with well defined boundaries.
      PubDate: 2016-08-01
       
  • Crack identification using model reduction based on proper orthogonal
           decomposition coupled with radial basis functions
    • Abstract: Abstract This work deals with the crack identification using model reduction based on the proper orthogonal decomposition method. The proposed inverse problem consists of the estimation of the crack length and its position in a plate using boundary displacements as input data. Genetic algorithm and particle swarm optimization were applied for the minimization of the error function expressed as the difference between the boundary displacements of the actual crack and those of the estimated crack. It was found that the proposed approach is able to accurately estimate crack size and detect its location. The stability of the identification algorithm was tested against measurement uncertainty by introducing a white Gaussian noise in the input data. The approach showed high stability for noise levels lower than 5 %. The efficiency of the approach using small number of sensor points was also demonstrated.
      PubDate: 2016-08-01
       
  • On the (non-)optimality of Michell structures
    • Abstract: Abstract Optimal analytical Michell frame structures have been extensively used as benchmark examples in topology optimization, including truss, frame, homogenization, density and level-set based approaches. However, as we will point out, partly the interpretation of Michell’s structural continua as discrete frame structures is not accurate and partly, it turns out that limiting structural topology to frame-like structures is a rather severe design restriction and results in structures that are quite far from being stiffness optimal. The paper discusses the interpretation of Michell’s theory in the context of numerical topology optimization and compares various topology optimization results obtained with the frame restriction to cases with no design restrictions. For all examples considered, the true stiffness optimal structures are composed of sheets (2D) or closed-walled shell structures (3D) with variable thickness. For optimization problems with one load case, numerical results in two and three dimensions indicate that stiffness can be increased by up to 80 % when dropping the frame restriction. For simple loading situations, studies based on optimal microstructures reveal theoretical gains of +200 %. It is also demonstrated how too coarse design discretizations in 3D can result in unintended restrictions on the design freedom and achievable compliance.
      PubDate: 2016-08-01
       
  • Two-scale topology design optimization of stiffened or porous plate
           subject to out-of-plane buckling constraint
    • Abstract: Abstract This paper studies maximum out-of-plane buckling load design of thin bending plates for a given amount of material. Two kinds of plates are considered. One is made of periodic homogeneous porous material. Another is uniformly stiffened solid plate. The plate material, thickness, design domain of its middle plane and boundary conditions are given. The pattern of prescribed in-plane external load or displacements along the part of boundaries, which move freely, is given. Both plate topology and micro-structural topology of porous material or stiffener layout are concurrently optimized. The artificial element material densities in both macro and micro-scale are chosen as design variables. The volume preserving nonlinear density filter is applied to obtain the black-white optimum topology and comparison of its different sensitivities is made to show the reason for oscillation during optimization process in Appendix. The new numerical implementation of asymptotic homogenization method (NIAH, Cheng (Acta Mech Sinica 29(4): 550–556, 2013) and Cai (Int J Solids Struct 51(1), 284–292, 2014) is applied to homogenization of periodic plate structures and analytic sensitivity analysis of effective stiffness with respect to the topological design variables in both macro-scale and micro-scale. On basis of that, this paper implements the sensitivity analysis of out-of-plane buckling load by using commercial FEA software and enables the application of gradient-based search algorithm in optimization. Several numerical implementation details are discussed. Three numerical examples are given to show the validity of this method.
      PubDate: 2016-07-16
       
  • Fluid flow topology optimization in PolyTop : stability and computational
           implementation
    • Abstract: Abstract We present a Matlab implementation of topology optimization for fluid flow problems in the educational computer code PolyTop (Talischi et al. 2012b). The underlying formulation is the well-established porosity approach of Borrvall and Petersson (2003), wherein a dissipative term is introduced to impede the flow in the solid (non-fluid) regions. Polygonal finite elements are used to obtain a stable low-order discretization of the governing Stokes equations for incompressible viscous flow. As a result, the same mesh represents the design field as well as the velocity and pressure fields that characterize its response. Owing to the modular structure of PolyTop, incorporating new physics, in this case modeling fluid flow, involves changes that are limited mainly to the analysis routine. We provide several numerical examples to illustrate the capabilities and use of the code. To illustrate the modularity of the present approach, we extend the implementation to accommodate alternative formulations and cost functions. These include topology optimization formulations where both viscosity and inverse permeability are functions of the design; and flow control where the velocity at a certain location in the domain is maximized in a prescribed direction.
      PubDate: 2016-07-15
       
  • Bending of beams of arbitrary cross sections - optimal design by
           analytical formulae
    • Abstract: Abstract The paper deals with the conceptual design of a beam under bending. The common problem of designing a beam in a state of pure bending is discussed in the framework of Pareto-optimality theory. The analytical formulation of the Pareto-optimal set is derived by using a procedure based on the reformulation of the Fritz John Pareto-optimality conditions. The shape of the cross section of the beam is defined by a number of design variables pertaining to the optimization process by means of efficiency factors. Such efficiency factors are able to describe the bending properties of any beam cross section and can be used to derive analytical formulae. Design performance is determined by the combination of cross section shape, material and process. Simple expressions for the Pareto-optimal set of a beam of arbitrary cross section shape under bending are derived. This expression can be used at the very early stage of the design to choose a possible cross section shape and material for the beam among optimal solutions.
      PubDate: 2016-07-15
       
  • Nonparametric approach for uncertainty-based multidisciplinary design
           optimization considering limited data
    • Abstract: Abstract Uncertainty-based multidisciplinary design optimization (UMDO) has been widely acknowledged as an advanced methodology to address competing objectives and reliable constraints of complex systems by coupling relationship of disciplines involved in the system. UMDO process consists of three parts. Two parts are to define the system with uncertainty and to formulate the design optimization problem. The third part is to quantitatively analyze the uncertainty of the system output considering the uncertainty propagation in the multidiscipline analysis. One of the major issues in the UMDO research is that the uncertainty propagation makes uncertainty analysis difficult in the complex system. The conventional methods are based on the parametric approach could possibly cause the error when the parametric approach has ill-estimated distribution because data is often insufficient or limited. Therefore, it is required to develop a nonparametric approach to directly use data. In this work, the nonparametric approach for uncertainty-based multidisciplinary design optimization considering limited data is proposed. To handle limited data, three processes are also adopted. To verify the performance of the proposed method, mathematical and engineering examples are illustrated.
      PubDate: 2016-07-13
       
  • Optimization of retaining wall design using evolutionary algorithms
    • Abstract: Abstract This paper explores the performance of three evolutionary optimization methods, differential evolution (DE), evolutionary strategy (ES) and biogeography based optimization algorithm (BBO), for nonlinear constrained optimum design of a cantilever retaining wall. These algorithms are based on biological contests for survival and reproduction. The retaining wall optimization problem consists of two criteria, geotechnical stability and structural strength, while the final design minimizes an objective function. The objective function is defined in terms of both cost and weight. Constraints are applied using the penalty function method. The efficiency of the proposed method is examined by means of two numerical retaining wall design examples, one with a base shear key and one without a base shear key. The final designs are compared to the ones determined by genetic algorithms as classical metaheuristic optimization methods. The design results and convergence rate of the BBO algorithm show a significantly better performance than the other algorithms in both design cases.
      PubDate: 2016-07-13
       
 
 
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