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CIVIL ENGINEERING (173 journals)                  1 2     

ACI Structural Journal     Full-text available via subscription   (Followers: 10)
Acta Polytechnica : Journal of Advanced Engineering     Open Access  
Acta Structilia : Journal for the Physical and Development Sciences     Open Access   (Followers: 2)
Advances in Civil Engineering     Open Access   (Followers: 32)
Advances in Structural Engineering     Full-text available via subscription   (Followers: 19)
Ambiente Construído     Open Access   (Followers: 2)
American Journal of Civil Engineering and Architecture     Open Access   (Followers: 23)
Architectural Engineering     Open Access   (Followers: 7)
Archives of Civil Engineering     Open Access   (Followers: 8)
Archives of Hydro-Engineering and Environmental Mechanics     Open Access   (Followers: 2)
ATBU Journal of Environmental Technology     Open Access   (Followers: 2)
Australian Journal of Structural Engineering     Full-text available via subscription   (Followers: 5)
Baltic Journal of Road and Bridge Engineering     Full-text available via subscription   (Followers: 3)
BER : Building and Construction : Full Survey     Full-text available via subscription   (Followers: 10)
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: 1)
Bridge Structures : Assessment, Design and Construction     Hybrid Journal   (Followers: 15)
Building and Environment     Hybrid Journal   (Followers: 15)
Building Women     Full-text available via subscription  
Built Environment Project and Asset Management     Hybrid Journal   (Followers: 17)
Bulletin of Pridniprovsk State Academy of Civil Engineering and Architecture     Open Access   (Followers: 2)
Canadian Journal of Civil Engineering     Full-text available via subscription   (Followers: 14)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 4)
Case Studies in Nondestructive Testing and Evaluation     Open Access   (Followers: 1)
Case Studies in Structural Engineering     Open Access  
Cement and Concrete Composites     Hybrid Journal   (Followers: 12)
Challenge Journal of Structural Mechanics     Open Access   (Followers: 4)
Change Over Time     Full-text available via subscription   (Followers: 4)
Civil and Environmental Engineering     Open Access   (Followers: 3)
Civil And Environmental Engineering Reports     Open Access   (Followers: 2)
Civil and Environmental Research     Open Access   (Followers: 17)
Civil Engineering     Hybrid Journal   (Followers: 14)
Civil Engineering = Siviele Ingenieurswese     Full-text available via subscription   (Followers: 5)
Civil Engineering and Architecture     Open Access   (Followers: 6)
Civil Engineering and Environmental Systems     Hybrid Journal   (Followers: 5)
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: 193)
Computer-aided Civil and Infrastructure Engineering     Hybrid Journal   (Followers: 9)
Computers & Structures     Hybrid Journal   (Followers: 26)
Concrete Research Letters     Open Access   (Followers: 2)
Constructii : Journal of Civil Engineering Research     Open Access   (Followers: 10)
Construction Economics and Building     Open Access  
Construction Engineering     Open Access   (Followers: 4)
Construction Management and Economics     Hybrid Journal   (Followers: 30)
Construction Science     Open Access   (Followers: 1)
Constructive Approximation     Hybrid Journal  
Curved and Layered Structures     Open Access  
DFI Journal : The Journal of the Deep Foundations Institute     Hybrid Journal  
Earthquake Engineering and Structural Dynamics     Hybrid Journal   (Followers: 13)
Enfoque UTE     Open Access   (Followers: 1)
Engineering Project Organization Journal     Hybrid Journal   (Followers: 5)
Engineering Structures     Hybrid Journal   (Followers: 13)
Engineering Structures and Technologies     Hybrid Journal   (Followers: 2)
Engineering, Construction and Architectural Management     Hybrid Journal   (Followers: 16)
Environmental Geotechnics     Open Access   (Followers: 3)
European Journal of Environmental and Civil Engineering     Hybrid Journal   (Followers: 5)
Fatigue & Fracture of Engineering Materials and Structures     Hybrid Journal   (Followers: 14)
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: 6)
Geomaterials     Open Access   (Followers: 2)
Geosystem Engineering     Hybrid Journal   (Followers: 3)
Geotechnik     Hybrid Journal   (Followers: 1)
Géotechnique Letters     Hybrid Journal   (Followers: 4)
HBRC Journal     Open Access   (Followers: 2)
Hormigón y Acero     Full-text available via subscription  
HVAC&R Research     Hybrid Journal   (Followers: 1)
Indoor and Built Environment     Hybrid Journal   (Followers: 2)
Infrastructure Asset Management     Full-text available via subscription  
Ingenio Magno     Open Access  
Insight - Non-Destructive Testing and Condition Monitoring     Full-text available via subscription   (Followers: 9)
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: 6)
International Journal of Concrete Structures and Materials     Open Access   (Followers: 8)
International Journal of Condition Monitoring     Full-text available via subscription   (Followers: 1)
International Journal of Construction Engineering and Management     Open Access   (Followers: 6)
International Journal of Geosynthetics and Ground Engineering     Full-text available via subscription   (Followers: 1)
International Journal of Protective Structures     Full-text available via subscription   (Followers: 6)
International Journal of Steel Structures     Hybrid Journal   (Followers: 4)
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: 6)
International Journal of Sustainable Built Environment     Open Access   (Followers: 4)
International Journal of Sustainable Construction Engineering and Technology     Open Access   (Followers: 11)
International Journal on Pavement Engineering & Asphalt Technology     Open Access   (Followers: 3)
Journal of Accessibility and Design for All     Open Access   (Followers: 7)
Journal of Bridge Engineering     Full-text available via subscription   (Followers: 18)
Journal of Building Engineering     Hybrid Journal  
Journal of Building Materials and Structures     Open Access  
Journal of Building Performance Simulation     Hybrid Journal   (Followers: 5)
Journal of Civil Engineering and Construction Technology     Open Access   (Followers: 3)
Journal of Civil Engineering and Management     Hybrid Journal   (Followers: 7)
Journal of Civil Engineering and Science     Open Access   (Followers: 13)
Journal of Civil Engineering Research     Open Access   (Followers: 12)

        1 2     

Journal Cover   Structural and Multidisciplinary Optimization
  [SJR: 1.825]   [H-I: 61]   [7 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  [2276 journals]
  • Shape preserving design with structural topology optimization
    • Abstract: Abstract The purpose of this paper is to demonstrate a shape preserving topology optimization design approach to suppress the warping deformation of local structural domains. As structural deformation consists of rigid body motion and warping deformation, we propose using the elastic strain energy of the local domain to measure the warping deformation. Constraint on the local strain energy is then introduced into a standard compliance based topology optimization to obtain the shape preserving effect. Moreover, in the cases of shape preserving for multiple key points and cavities, i.e. when the local strain energies are unavailable, the idea of Artificial Weak Element (AWE) is introduced to measure and constrain the local warping deformation. Several numerical examples are tested here. The optimized results indicate that the local strain energy constraints on the shape preserving domains can suppress the warping deformation effectively in both simple illustrative examples and complicated engineering examples. Further discussions on the failure of structural load carrying path and the influence of the shape preserving constraint is also presented.
      PubDate: 2015-11-28
  • Design of sound phase diffusers by means of multiobjective optimization
           approach using ev-MOGA evolutionary algorithm
    • Abstract: Abstract In this paper a new approach to design sound phase diffusers is presented. The acoustic properties of such diffusers are usually increased by using single objective optimization methods. Here we propose the use of a multiobjective (MO) approach to design them in order to take into account several conflicting characteristic simultaneously. Three different MO problems are posed to consider various scenarios where fundamentally the objective is to maximize the normalized diffusion coefficient (following the corresponding Audio Engineering Society standard) for the so-called medium frequencies. This single objective could be divided into other several objectives to adjust performances to designer preferences. A multi-objective evolutionary algorithm (called ev-MOGA) is used to characterize the Pareto front in a smart way. ev-MOGA is modified, by using integer codification and tuning some of its genetic operators, to adapt it to the new requirements. Special interest is posed in selecting the diffusers codification properly to eliminate duplicities that would produce a multimodal problem. Precision in the manufacturing process is taking into account in the diffuser codification causing, that the number of different diffusers are quantified. Robust considerations related with the precision manufacturing process are considered in the decision making process. Finally, an optimal diffuser is selected considering designer preferences.
      PubDate: 2015-11-23
  • On the formulation and implementation of geometric and manufacturing
           constraints in node–based shape optimization
    • Abstract: Abstract We introduce a novel method to handle geometrical and manufacturing constraints in parameter–free shape optimization. Therefore the design node coordinates are split in two sets where one set is declared as new design variables and the other set is coupled to the new design variables such that the geometrical constraint is fulfilled. Thereby no additional equations are appended to the optimization problem. In contrast the implementation of a demolding constraint is presented by formulating inequality constraints which indeed have to be attached to the optimization problem. In the context of a sensitivity–based shape optimization approach all manufacturing constraints have to be formulated in terms of the finite element node coordinates such that first order gradients with respect to the design node coordinates can be derived.
      PubDate: 2015-11-23
  • Isogeometric shape optimization of trimmed shell structures
    • Abstract: Abstract In most of structural analyses and optimizations using the conventional isogeometric analysis, handling of trimmed or topologically complex geometries is difficult and awkward. A trimmed or topologically complex geometry is normally modeled with multiple untrimmed patches due to the tensor-product form of a Non-Uniform Rational B-Spline (NURBS) surface, and then the patches are put together for analysis. In the present work, the isogeometric shape optimization of trimmed shell structures using the information of trimmed NURBS surfaces is proposed. To treat the trimmed shell structures efficiently, two-dimensional Trimmed Surface Analysis (TSA) which is the isogeometric approach for treating a topologically complex geometry with a single patch is extended and adopted to the analysis and optimization of shell structures. Not only the coordinates of shell surface control points, but also the coordinates of trimming curve control points are chosen as design variables so that the curvatures of shell surface as well as the trimmed boundaries can be varied during the optimization. The degenerated shell based on Reissner-Mindlin theory is formulated with exact direction vectors and their analytic derivatives. Method of Moving Asymptotes (MMA) is used as the optimization algorithm, and the shape sensitivities with respect to the coordinates of surface control points and trimming curve control points are formulated with exact direction vectors and their analytic derivatives. The developed sensitivity formulations are validated by comparing with the results of Finite Difference Method (FDM), and they show excellent agreements. Numerical examples are treated to confirm the ability of the proposed approach.
      PubDate: 2015-11-21
  • Structural topology optimization under rotating load
    • Abstract: Abstract In this work, attempts are made for the first time to carry out structural topology optimization under rotating load caused by the centrifugal force of mass unbalance in rotating machinery. As is known, a rotating load can be decomposed into two harmonic excitations in two orthogonal directions with phase difference, the considered topology optimization problem is handled under two associated harmonic excitations. Due to the presence of phase difference, it is however more complicated than existing works related to harmonic excitations in phase. As the structural response is time-dependent, two topology optimization formulations are thus established to minimize the dynamic compliance and the maximum displacement amplitude of the loaded node over a period, respectively. Meanwhile, harmonic analysis of the structure is carried out by means of the full method and the related sensitivity analysis is presented for both optimization formulations as well. Finally, validities and effects of the proposed optimization formulations are illustrated and compared through typical numerical tests. It is found that both formulations have the ability to reduce the structure vibration caused by the rotating load and similar configurations are obtained after optimization in most tests.
      PubDate: 2015-11-21
  • Optimization of load–carrying and heat–insulating
           multi–layered thin–walled structures based on bionics using
           genetic algorithm
    • Abstract: Abstract Topology optimization to minimize the bottom–layer temperature and the structure compliance of the multi–layered thin–walled structure is carried out in this paper. A multi–layered thin–walled structure with improved performances in load–carrying and heat insulation inspired by a species of oceanic gastropods found on a hot and highly pressurized deep–sea floor is proposed. Using genetic algorithm to perform the optimization process, it is proved that the optimal topology under integrated thermal and load conditions is a sandwich structure of three layers similar to the original bionic structure of the oceanic gastropods. Soft layer with good heat insulation is placed as the middle layer, whereas hard layers with fast heat transmission are placed as the top and bottom layers to carry load. The concept of bionic three–layered structure is then applied to the skin design of an airfoil. The analysis for aerodynamic heating of the airfoil with different skin structures shows that the bionic multi–layered structure is an optimal design in both layer thickness and layer sequence.
      PubDate: 2015-11-21
  • Optimal layout of multiple bi-modulus materials
    • Abstract: Abstract A modified solid isotropic material with penalization (SIMP) method is proposed for solving layout optimization problems of multiple bi-modulus materials in a continuum. In the present algorithm, each bi-modulus material is replaced by two distinct isotropic materials to avoid structural reanalysis for each update of the design domains. To reduce the error in local stiffness due to the material replacement, the modification factor of each finite element is calculated according to the local stress state and the moduli used in the previous structural analysis. Three numerical examples are considered to demonstrate the validity and applicability of the present approach. Numerical results show that the final layout of materials is determined by factors that include the moduli difference of each bi-modulus material and the difference among material moduli.
      PubDate: 2015-11-20
  • Deterministic versus reliability-based topology optimization of
           aeronautical structures
    • Abstract: Abstract Aircraft design is a challenging process which is constantly looking for developing new and lighter structural components. The application of topology optimization techniques is growing widespread in the aeronautical industry as it has proven to be highly useful for saving important weight amounts in recent aircraft designs. The objective of this research is to obtain optimal and novel aeronautical architectures through topology optimization while considering uncertainty in loads and material properties. For this, a methodology that combines the Sequential Optimization and Reliability Assessment (SORA) with external optimization software has been developed in order to perform Reliability-Based Topology Optimization (RBTO). The methodology is then compared against the classical way of obtaining novel architectures in aeronautical industry, which lie in the application of Deterministic Topology Optimization (DTO) considering partial safety factors in some data influencing the structural responses. The comparison draws weight savings of up to 3 % in the examples proposed when applying RBTO which could be highly significant in an aircraft structure. Moreover it has been proven that when performing a RBTO approach the layout of the final design can be different depending on the safety level required, which may influence the next phases of aircraft design process.
      PubDate: 2015-11-20
  • Structural topology optimization under constraints on instantaneous
           failure probability
    • Abstract: Abstract Accurate prediction of stochastic responses of a structure caused by natural hazards or operations of non-structural components is crucial to achieve an effective design. In this regard, it is of great significance to incorporate the impact of uncertainty into topology optimization of structures under constraints on their stochastic responses. Despite recent technological advances, the theoretical framework remains inadequate to overcome computational challenges of incorporating stochastic responses to topology optimization. Thus, this paper presents a theoretical framework that integrates random vibration theories with topology optimization using a discrete representation of stochastic excitations. This paper also discusses the development of parameter sensitivity of dynamic responses in order to enable the use of efficient gradient-based optimization algorithms. The proposed topology optimization framework and sensitivity method enable efficient topology optimization of structures under stochastic excitations, which is successfully demonstrated by numerical examples of structures under stochastic ground motion excitations.
      PubDate: 2015-11-20
  • An efficient approach to reliability-based topology optimization for
           continua under material uncertainty
    • Abstract: Abstract This contribution presents a computationally efficient method for reliability-based topology optimization for continuum domains under material properties uncertainty. Material Young’s modulus is assumed to be lognormally distributed and correlated within the domain. The computational efficiency is achieved through estimating the response statistics with stochastic perturbation of second order, using these statistics to fit an appropriate distribution that follows the empirical distribution of the response, and employing an efficient gradient-based optimizer. Two widely-studied topology optimization problems are examined and the changes in the optimized topology is discussed for various levels of target reliability and correlation strength. Accuracy of the proposed algorithm is verified using Monte Carlo simulation.
      PubDate: 2015-11-20
  • Spot weld reduction methods for automotive structures
    • Abstract: Abstract Spot welds are commonly used to join steel sheets in automotive structures. The number and layout of these spot welds are vital for the performance of the structure. However, reducing the number of spot welds will cut both production time and cost. This article presents three different methods of reducing the number of spot welds in automotive structures: ranking-based selection, topology optimization and size optimization of a parameterized model. The methods are compared in a simple example and it is found that the latter two methods have the best potential of reducing the number of spot welds. Topology optimization requires less preparation and computational effort as compared to size optimization of a parameterized model. However, the method is primarily suitable for studies where load cases involving linear systems are judged to be most important. Otherwise, size optimization of a parameterized model is probably a better choice. The topology optimization approach is successfully demonstrated in a full-scale industrial application example and confirms that the method is useful within contemporary product development.
      PubDate: 2015-11-19
  • A semi-single-loop method using approximation of most probable point for
           reliability-based design optimization
    • Abstract: Abstract A semi-single-loop structure for an efficient reliability-based design optimization (RBDO) is proposed in this study. This structure makes up for the weaknesses of the double-loop method and the single-loop method. In the double-loop method, a heavy computational cost could be required due to an inherent nature of a nested structure. The single-loop method lacks robustness, which means its performance is sensitively affected by several factors. A decoupled method has also been developed in an effort to improve the efficiency of RBDO. Although it separates the nested structure, it retains a double-loop structure. In the semi-single-loop method, a sensitivity analysis of the reliability analysis result is performed in order to approximate a most probable point (MPP). According to the validity of the approximation, the approximated MPP is used for the evaluation of probabilistic constraints. As long as the approximation of MPP is valid, the proposed method has a complete single-loop structure with great efficiency and assured accuracy. If the approximation of MPP loses its validity, a fast reliability analysis is carried out by selecting the approximated MPP as a starting point. The robustness and accuracy of the proposed method are fully ensured due to the concept of checking the validity of the approximated MPP. Numerical examples are tested to verify these advantages of the proposed method and to compare the results here to those of existing RBDO methods.
      PubDate: 2015-11-18
  • Relaxation approach to topology optimization of frame structure under
           frequency constraint
    • Abstract: Abstract This paper deals with the frame topology optimization under the frequency constraint and proposes an algorithm that solves a sequence of relaxation problems to obtain a local optimal solution with high quality. It is known that an optimal solution of this problem often has multiple eigenvalues and the feasible set is disconnected. Due to these two difficulties, conventional nonlinear programming approaches often converge to a local optimal solution that is unacceptable from a practical point of view. In this paper, we formulate the frequency constraint as a positive semidefinite constraint of a certain symmetric matrix, and then relax this constraint to make the feasible set connected. The proposed algorithm solves a sequence of the relaxation problems with gradually decreasing the relaxation parameter. The positive semidefinite constraint is treated with the logarithmic barrier function and, hence, the algorithm finds no difficulty in multiple eigenvalues of a solution. Numerical experiments show that global optimal solutions, or at least local optimal solutions with high qualities, can be obtained with the proposed algorithm.
      PubDate: 2015-11-07
  • Design of piezoelectric modal filters by simultaneously optimizing the
           structure layout and the electrode profile
    • Abstract: Abstract Modal transducers can be designed by optimizing the polarity of the electrode which covers the piezoelectric layers bonded to the host structure. This paper is intended as a continuation of our previous work (Donoso and Bellido J Appl Mech 57:434–441, 2009a) to make better the performance of such piezoelectric devices by simultaneously optimizing the structure layout and the electrode profile. As the host structure is not longer fixed, the typical drawbacks in eigenproblem optimization such as spurious modes, mode tracking and switching or repeated eigenvalues soon appear. Further, our model has the novel issue that both cost and constraints explicitly depend on mode shapes. Moreover, due to the physics of the problem, the appearance of large gray areas is another pitfall to be solved. Our proposed approach overcomes all these difficulties with success and let obtain nearly 0-1 designs that improve the existing optimal electrode profiles over a homogeneous plate.
      PubDate: 2015-11-07
  • An algorithm for eradicating the effects of void elements on structural
           topology optimization for nonlinear compliance
    • Abstract: Abstract This paper presents an efficient algorithm for structural topology optimization with material and/or geometric nonlinearities using the moving iso-surface threshold (MIST) method. In this algorithm, all finite element analyses (FEA) are conducted for sub-domains with solid and grey elements via removing all void elements, whereas the response function is constructed in the full design domain. This algorithm allows the removed void elements to be involved in design variable update and to reappear in subsequent iterations. As there are solid materials only in the final optimal topology, problems such as ‘layering’ and ‘islanding’ caused by void elements in topology optimization for structures considering large deformations are completely eradicated. Challenges such as ‘material reappearance’ and ‘discontinuity’ owing to the removal of void elements are resolved. Numerical results for three typical structures and their comparison with those in the literature are presented to validate the present algorithm.
      PubDate: 2015-11-05
  • Polygonal multiresolution topology optimization (PolyMTOP) for structural
    • Abstract: Abstract We use versatile polygonal elements along with a multiresolution scheme for topology optimization to achieve computationally efficient and high resolution designs for structural dynamics problems. The multiresolution scheme uses a coarse finite element mesh to perform the analysis, a fine design variable mesh for the optimization and a fine density variable mesh to represent the material distribution. The finite element discretization employs a conforming finite element mesh. The design variable and density discretizations employ either matching or non-matching grids to provide a finer discretization for the density and design variables. Examples are shown for the optimization of structural eigenfrequencies and forced vibration problems.
      PubDate: 2015-11-05
  • Interior layout topology optimization of a reactive muffler
    • Abstract: Abstract This article presents a material distribution method that is tailored to the interior design of reactive mufflers. Such devices are typically acoustically small, except in the length direction, and their interior consists of a combination of pipes, expansions, contractions, and Helmholtz resonators. In order to design the interior layout using material distribution optimization, it is necessary to be able to resolve thin sound-hard materials as well as thin sheets with a given acoustic impedance, such as perforated plates, and manage small channels to Helmholtz resonators. We develop a method that uses an anisotropic design filter in combination with a fine mesh in order to control the minimum thickness separately in different directions. A two-stage post processing procedure is used to control openings to resonators, and embedded thin impedance surfaces are modeled by a mortar-element method. Numerical results demonstrate that the approach can produce mufflers with high transmission loss for a broad range of frequencies. The optimized mufflers include components that resemble combinations of expansion chambers, cylindrical pipes, and Helmholtz resonators.
      PubDate: 2015-11-03
  • Pareto-based negotiation in distributed multidisciplinary design
    • Abstract: Abstract The process of distributed engineering design calls for a methodology making use of the most recent advances in optimization-based design including multidisciplinary and multiobjective optimization. In distributed design, the participating teams do not have access to the design problems of other teams but may exchange limited information about their own current designs, making negotiation among themselves a key mechanism to reach a desired compromise which, nevertheless, is also a Pareto design to the original problem. A mathematical model of this distributed but decomposable design process is posed and solved using Lagrangian relaxation, while Pareto optimality is equivalently converted to single-objective optimality by means of multicriteria decision making strategies. The proposed coordination algorithm allows negotiation among the teams (subproblems) by sharing only limited information that is restricted to values of optimization quantities. The proposed modeling and solution scheme is applied to a numerical example representing the design of vehicle subsystems and components.
      PubDate: 2015-11-03
  • Topology optimization of plate structures subject to initial excitations
           for minimum dynamic performance index
    • Abstract: Abstract This paper studies optimal topology design of damped vibrating plate structures subject to initial excitations. The design objective is to minimize an integrated square performance measure. The artificial density of the plate element is the topology design variable and the material volume is given. The Lyapunov’s second method is applied to reduce the calculation of performance measure to the solution of the Lyapunov equation. An adjoint sensitivity analysis method is used, which only needs to solve the Lyapunov equation twice. However, when the problem has a large number of degrees of freedom, the solution process of Lyapunov equation is computational costly. Thus, the full model is transformed to a reduced space by mode reduction method. To further reduce the scale of reduced model, we propose a mode screen method to decrease the number of eigenmodes. Numerical examples of optimum topology design of bending plates are presented for illustrating validity and efficiency of our new algorithm.
      PubDate: 2015-11-02
  • Optimal design of dome truss structures with dynamic frequency constraints
    • Abstract: Abstract Controlling the values of natural frequencies of a structure plays an important role to keep the dynamic behavior of structures in a desirable level. This paper is concerned with the optimal design of large-scale dome structures with multiple natural frequency constraints. This optimization problem is highly nonlinear with several local optimums in its search space. The idea of cascading, which allows a single optimization problem to be tackled with a number of autonomous optimization stages is used. The procedure utilized in this paper reduces the objective function value over a number of optimization stages by initially operating on a small number of design variables, which is gradually increased stage after stage. In order to show the effect of using coarsening of variables for handling the optimization problem, independent of the effect of the algorithm, the recently developed approach (enhanced colliding bodies optimization) is employed in the entire stages of the present method. Besides, we want to demonstrate the positive effect of using multi-DVC cascade optimization procedure even if the utilized algorithm itself is a powerful method. In order to test the performance of the algorithm, four dome truss design examples with 120, 600, 1180 and 1410 elements are optimized. The numerical results prove that the utilized method is an effective tool for finding optimum design of structures with frequency constraints.
      PubDate: 2015-10-31
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