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  Subjects -> ENGINEERING (Total: 2156 journals)
    - CHEMICAL ENGINEERING (186 journals)
    - CIVIL ENGINEERING (168 journals)
    - ELECTRICAL ENGINEERING (93 journals)
    - ENGINEERING (1164 journals)
    - ENGINEERING MECHANICS AND MATERIALS (355 journals)
    - HYDRAULIC ENGINEERING (55 journals)
    - INDUSTRIAL ENGINEERING (54 journals)
    - MECHANICAL ENGINEERING (81 journals)

CIVIL ENGINEERING (168 journals)                  1 2     

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: 2)
Advances in Civil Engineering     Open Access   (Followers: 30)
Advances in Structural Engineering     Full-text available via subscription   (Followers: 21)
Ambiente Construído     Open Access   (Followers: 2)
American Journal of Civil Engineering and Architecture     Open Access   (Followers: 21)
Architectural Engineering     Open Access   (Followers: 5)
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: 1)
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: 2)
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: 5)
Berkeley Planning Journal     Open Access   (Followers: 5)
Bioinspired Materials     Open Access  
Bridge Structures : Assessment, Design and Construction     Hybrid Journal   (Followers: 15)
Building and Environment     Hybrid Journal   (Followers: 13)
Building Women     Full-text available via subscription  
Built Environment Project and Asset Management     Hybrid Journal   (Followers: 16)
Canadian Journal of Civil Engineering     Full-text available via subscription   (Followers: 15)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 4)
Case Studies in Nondestructive Testing and Evaluation     Open Access  
Case Studies in Structural Engineering     Open Access  
Cement and Concrete Composites     Hybrid Journal   (Followers: 13)
Change Over Time     Full-text available via subscription   (Followers: 3)
Civil and Environmental Engineering     Open Access   (Followers: 1)
Civil And Environmental Engineering Reports     Open Access  
Civil and Environmental Research     Open Access   (Followers: 14)
Civil Engineering     Hybrid Journal   (Followers: 12)
Civil Engineering = Siviele Ingenieurswese     Full-text available via subscription   (Followers: 5)
Civil Engineering and Architecture     Open Access   (Followers: 4)
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: 129)
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: 9)
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: 2)
Engineering Project Organization Journal     Hybrid Journal   (Followers: 4)
Engineering Structures     Hybrid Journal   (Followers: 14)
Engineering Structures and Technologies     Hybrid Journal   (Followers: 2)
Engineering, Construction and Architectural Management     Hybrid Journal   (Followers: 16)
Environmental Geotechnics     Open Access   (Followers: 2)
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   (Followers: 1)
Frontiers of Structural and Civil Engineering     Hybrid Journal   (Followers: 5)
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: 1)
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: 7)
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: 7)
International Journal of Concrete Structures and Materials     Open Access   (Followers: 9)
International Journal of Condition Monitoring     Full-text available via subscription  
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: 5)
International Journal of Sustainable Built Environment     Open Access   (Followers: 3)
International Journal of Sustainable Construction Engineering and Technology     Open Access   (Followers: 10)
International Journal on Pavement Engineering & Asphalt Technology     Open Access   (Followers: 2)
Journal of Accessibility and Design for All     Open Access   (Followers: 6)
Journal of Advanced Research in Civil and Environmental Engineering     Open Access   (Followers: 1)
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: 13)
Journal of Civil Society     Hybrid Journal   (Followers: 3)
Journal of Civil Structural Health Monitoring     Hybrid Journal   (Followers: 3)
Journal of Composites     Open Access   (Followers: 41)

        1 2     

Journal Cover   Structural and Multidisciplinary Optimization
  [SJR: 1.825]   [H-I: 61]   [5 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  [2292 journals]
  • Minimization of vortex induced vibrations using Surrogate Based
           Optimization
    • Abstract: Abstract In this work we consider the application of optimization techniques in fluid-structure interaction (FSI) problems. An arbitrary Lagrangian Eulerian (ALE) finite element formulation, based on a Fractional Step Method is extended to deal with incompressible flow problems with moving interfaces. The vortex induced vibrations (VIV) phenomena are evaluated, and the reduction of such vibrations is attempted by using an acoustic excitation on the surface of the cylinder or by positioning a flat plate behind the cylinder, with the optima design parameters obtained through the minimization of the cylinder vibration. As the cost of FSI numerical simulation can be very high it is generally not feasible to couple the simulator directly to the optimizer. Therefore, a cheap surrogate model is used to capture the main trends of the objective and constraint functions. In this work we adopt Kriging data fitting approximation to build surrogate models to be used in the context of local optimization. The Sequential Approximate Optimization (SAO) strategy is used to solve the problem as a sequence of local problems. A trust region based framework is employed to adaptively update the design variable space for each local optimization. Sequential Quadratic Programming (SQP) is the algorithm of choice for the local problems. This optimizer will operate solely on the surrogates, which is smooth and also allows for the gradient computation. The integrated approach presented for optimization of FSI problems using surrogate models and the proposed strategy for sampling reuse leads to a robust and efficient tool, which were successful in solving the model problems analyzed. Also the proposed tool proved to be accurate and its performance confirms the efficient regularization of simulator numerical noise.
      PubDate: 2015-06-23
       
  • Optimization of three-dimensional truss-like periodic materials
           considering isotropy constraints
    • Abstract: Abstract In recent years, much attention has been directed to the study of ultralight periodic cellular materials, such as the so called Periodic Truss Materials (PTMs), which are made up of truss-like unit cells. Application of these materials has its best potential in structures subjected to multifunctional, and sometimes conflicting, engineering requirements. Hence, optimization techniques can be employed to help finding the shape of the optimal unit cell for a given multifunctional application. Although the result can be geometrically complex, this difficulty can be minored in view of modern additive manufacturing technologies. This work presents a parameter/topology optimization procedure to design the particular unit cell geometry (that is, finding the cross sections of the bars) that results in a macroscopic material with optimum homogenized elastic or/and thermal constitutive properties. Emphasis is devoted to analyze the effect of enforcing independently elastic or thermal isotropy in the macroscopic material behavior. Although isotropic behavior can be imposed through adequate cell symmetries, an equivalent effect can be achieved by satisfying equality constraints relating constitutive coefficients. A sequential quadratic programming algorithm (SQP) is adopted, thus enforcing equality constraints gradually and within a tolerance range. This results in an enlarged search space at intermediate stages, rendering an effective strategy to solve the optimization problem. Different 3D cases with engineering appeal are solved and the results discussed.
      PubDate: 2015-06-22
       
  • H-DGTP—a Heaviside-function based directional growth topology
           parameterization for design optimization of stiffener layout and height of
           thin-walled structures
    • Abstract: Abstract Plates with ribs or stiffeners (stiffened plates) have been widely used as primary or secondary load bearing structures. Such structures could be fabricated by casting – a conventional yet important manufacturing process, their load bearing capacities are strongly dependent on the layout and sizes of the stiffeners. Thus it is necessary to establish specific topology optimization model and algorithm to obtain optimum layout, sizes and shapes of the stiffeners with casting constraints being considered. In this paper, we propose a new Heaviside-function based directional growth topology parameterization (H-DGTP) of the casting constraints for simultaneously optimizing the layout and height of the stiffeners. By using the new explicit parameterization, we can obtain a clear stiffener layout with optimized height. The differentiability of the parameterization is obtained by the use of a smooth approximation of the Heaviside function. In order to be applicable to a non-uniform mesh, a base surface is introduced and the minimum length of a stiffener can be controlled. Several numerical examples are presented to show the validity of this method.
      PubDate: 2015-06-22
       
  • Creating geometrically robust designs for highly sensitive problems using
           topology optimization
    • Abstract: Abstract Resonance and wave-propagation problems are known to be highly sensitive towards parameter variations. This paper discusses topology optimization formulations for creating designs that perform robustly under spatial variations for acoustic cavity problems. For several structural problems, robust topology optimization methods have already proven their worth. However, it is shown that direct application of such methods is not suitable for the acoustic problem under consideration. A new double filter approach is suggested which makes robust optimization for spatial variations possible. Its effect and limitations are discussed. In addition, a known explicit penalization approach is considered for comparison. For near-uniform spatial variations it is shown that highly robust designs can be obtained using the double filter approach. It is finally demonstrated that taking non-uniform variations into account further improves the robustness of the designs.
      PubDate: 2015-06-21
       
  • On quasi-arithmetic mean based filters and their fast evaluation for
           large-scale topology optimization
    • Abstract: Abstract In material distribution topology optimization, restriction methods are routinely applied to obtain well-posed optimization problems and to achieve mesh-independence of the resulting designs. One of the most popular restriction methods is to use a filtering procedure. In this paper, we present a framework where the filtering process is viewed as a quasi-arithmetic mean (or generalized f-mean) over a neighborhood with the possible addition of an extra “projection step”. This framework includes the vast majority of available filters for topology optimization. The covered filtering procedures comprise three steps: (i) element-wise application of a function, (ii) computation of local averages, and (iii) element-wise application of another function. We present fast algorithms that apply this type of filters over polytope-shaped neighborhoods on regular meshes in two and three spatial dimensions. These algorithms have a computational cost that grows linearly with the number of elements and can be bounded irrespective of the filter radius.
      PubDate: 2015-06-21
       
  • In-plane material filters for the discrete material optimization method
    • Abstract: Abstract This paper presents in-plane material filters for the Discrete Material Optimization method used for optimizing laminated composite structures. The filters make it possible for engineers to specify a minimum length scale which governs the minimum size of areas with constant material continuity. Consequently, engineers can target the available production methods, and thereby increase its manufacturability while the optimizer is free to determine which material to apply together with an optimum location, shape, and size of these areas with constant material continuity. By doing so, engineers no longer have to group elements together in so-called patches, so to statically impose a minimum length scale. The proposed method imposes the minimum length scale through a standard density filter known from topology optimization of isotropic materials. This minimum length scale is generally referred to as the filter radius. However, the results show that the density filter alone gives designs with large measures of non-discreteness. In order to obtain near discrete designs an additional threshold projection filter is applied, so to push the physical design variables towards their discrete bounds. However, because the projection filter is a non-linear function of the design variables, the projected variables have to be re-scaled in a final so-called normalization filter. This is done to prevent the optimizer in creating superior, but non-physical pseudo-materials. The method is demonstrated on a series of minimum compliance examples together with a minimum mass example, and the results show that the method is indeed capable of imposing a minimum length scale onto the optimized layup.
      PubDate: 2015-06-21
       
  • A multi-objective differential evolution approach based on
           ε-elimination uniform-diversity for mechanism design
    • Abstract: Abstract In this paper, a new multi-objective uniform-diversity differential evolution (MUDE) algorithm is proposed and used for Pareto optimum design of mechanisms. The proposed algorithm uses a diversity preserving mechanism called the ε-elimination algorithm to improve the population diversity among the obtained Pareto front. The proposed algorithm is firstly tested on some constrained and unconstrained benchmarks proposed for the special session and competition on multi-objective optimizers held under IEEE CEC 2009. The inverted generational distance (IGD) measure is used to assess the performance of the algorithm. Secondly, the proposed algorithm has been used for multi-objective optimization of two different combinatorial case studies. The first case contains a two-degree of freedom leg mechanism with springs. Three conflicting objective functions that have been considered for Pareto optimization are namely, leg size, vertical actuating force, and the peak crank torque. The second case is a two-finger robot gripper mechanism with two conflicting objectives which are the difference between the maximum and minimum gripping force and the transmission ratio of actuated and experienced gripper forces. Comparisons of obtained Pareto fronts using the method of this work with those obtained in other references show significant improvements.
      PubDate: 2015-06-20
       
  • Multi-objective particle swarm optimization with preference information
           and its application in electric arc furnace steelmaking process
    • Abstract: Abstract In this paper, multi-objective particle swarm optimization with preference information (MOPSO-PI) has been proposed. In the proposed algorithm, the information entropy is employed for measuring the probability distribution of particles; the user’s preference information is represented as the ranking of each particle through the possible matrix. The optimal procedure is guided by the preference information since the global best performance of particle is randomly chosen among non-dominated solutions with higher ranking value in each iteration. Finally, the MOPSO-PI is applied to optimize the steelmaking process; the power supply curve obtained reduces the electric energy consumption, shortens the smelting time and prolongs the lifespan of the furnace lining. The application results show the effectiveness of the proposed algorithm.
      PubDate: 2015-06-20
       
  • Structural topology optimization for maximum linear buckling loads by
           using a moving iso-surface threshold method
    • Abstract: Abstract This paper investigates topology design optimization for maximizing critical buckling loads of thin-walled structures using a moving iso-surface threshold (MIST) method. Formulation for maximizing linear buckling loads with additional constraints on load-path continuity and lower bound of eigenvalue is firstly presented. New physical response functions are proposed and expressed in terms of the strain energy densities determined in the two-steps of finite element buckling analysis. A novel approach by introducing a connectivity coefficient is developed to ensure continuity of effective load-path in optimum topology. The lower bound of eigenvalue is defined to eliminate spurious localized buckling modes. The MIST algorithm and its interfaces with commercial finite element (FE) software are given in detail. Numerical results are presented for topology optimization of plate-like structures to maximize critical buckling forces or displacements considering in-plane and out-of-plane buckling respectively. The FE analyses of the re-meshed final solid topologies with and without void material reveal that the presence of the void material has a significant effect on the out-of-plane buckling loads and a minor influence on the in-plane buckling loads.
      PubDate: 2015-06-19
       
  • Stacking sequence optimization of horizontal axis wind turbine blade using
           FEA, ANN and GA
    • Abstract: Abstract The requirements for wind energy are significantly increasing for the sources of non-renewable energy is censoriously shortened and the awareness on green energy is emergent. The required energy from the wind turbine can be increased by optimally varying the aerodynamic considerations like aerofoil section, chord length, angle of attack, twist angle and the rotor diameter. However the blade may structurally fail, for the aerodynamic considerations are generally against the structural requirements. For example, the coefficient of lift can be increased with the reduced thickness but the structure may fail due to lacking of bending and torsional strength. Similarly, when the wind turbine blade radius is increased, the structure will have poor buckling strength. As the outer shape of a wind turbine blade and the thickness are determined based on the aerodynamic considerations, they are kept constant in this work and the buckling strength of the wind turbine structure is improved by optimally varying the ply orientations and stacking sequences at each section of the wind turbine blade. The difficulty due to high computational cost in the stacking sequence optimization of wind turbine blade is overcome by replacing finite element analysis using artificial neural network.
      PubDate: 2015-06-19
       
  • Materials selection for a set of multiple parts considering manufacturing
           costs and weight reduction with structural isoperformance using direct
           multisearch optimization
    • Abstract: Abstract Materials selection is a matter of great importance to engineering design and software tools are valuable to inform decisions in the early stages of product development. However, when a set of alternative materials is available for the different parts a product is made of, the question of what optimal material mix to choose for a group of parts is not trivial. The engineer/designer therefore goes about this in a part-by-part procedure. Optimizing each part per se can lead to a global sub-optimal solution from the product point of view. An optimization procedure to deal with products with multiple parts, each with discrete design variables, and able to determine the optimal solution assuming different objectives is therefore needed. To solve this multiobjective optimization problem, a new routine based on Direct MultiSearch (DMS) algorithm is created. Results from the Pareto front can help the designer to align his/hers materials selection for a complete set of materials with product attribute objectives, depending on the relative importance of each objective.
      PubDate: 2015-06-18
       
  • An improved soft-kill BESO algorithm for optimal distribution of single or
           multiple material phases
    • Abstract: Abstract Finding the optimum distribution of material phases in a multi-material structure is a frequent and important problem in structural engineering which involves topology optimization. The Bi-directional Evolutionary Structural Optimization (BESO) method is now a well-known topology optimization method. In this paper an improved soft-kill BESO algorithm is introduced which can handle both single and multiple material distribution problems. A new filtering scheme and a gradual procedure inspired by the continuation approach are used in this algorithm. Capabilities of the proposed method are demonstrated using different examples. It is shown that the proposed method can result in considerable improvements compared to the normal BESO algorithm particularly when solving problems involving very soft material or void phase.
      PubDate: 2015-06-16
       
  • A multi-objective reliability-based optimization of the crashworthiness of
           a metallic-GFRP impact absorber using hybrid approximations
    • Abstract: Abstract In the field of automotive safety, the lightweight design of crash absorbers is an important research topic with a direct effect on the occupant safety levels. The design of these absorbers usually requires an optimization of their crashworthiness, which can include multi-objective and reliability-based optimization techniques. This process is very time-consuming, and in spite of the continuous growing of computational power, the problem needs a reliable solving scheme. The use of surrogate models and parallel computing are suitable alternatives to deal with this issue. However, the strongly non-linear response functions obtained from the finite element simulations need careful treatment. This work contributes with the application of a surrogate-based reliability-based design optimization method to an original design of a crash absorber made of metal and a glass-fiber reinforced polymer which is subjected to a frontal impact. Multi-adaptive regression splines models are employed to emulate the original responses, and three different approaches in the sampling stage of the method are compared. The absorbed energy and the mass of the element are considered as objective functions, while the peak value of the force transmitted to the occupants of the vehicle is the design constraint. A discussion of the employed materials is presented and the proposed approaches are compared. Finally, several Pareto fronts are obtained as a solution to the probabilistic problem. Results show that a combination of aluminum and glass fiber reinforced polymer is optimum for this problem, and some design rules are offered.
      PubDate: 2015-06-12
       
  • Trajectory driven multidisciplinary design optimization of a sub-orbital
           spaceplane using non-stationary Gaussian process
    • Abstract: Abstract This paper presents the multidisciplinary optimization of an aircraft carried sub-orbital spaceplane. The optimization process focused on three disciplines: the aerodynamics, the structure and the trajectory. The optimization of the spaceplane geometry was coupled with the optimization of its trajectory. The structural weight was estimated using empirical formulas. The trajectory was optimized using a pseudo-spectral approach with an automated mesh refinement that allowed for increasing the sparsity of the Jacobian of the constraints. The aerodynamics of the spaceplane was computed using an Euler code and the results were used to create a surrogate model based on a non-stationary Gaussian process procedure that was specially developed for this study.
      PubDate: 2015-06-11
       
  • Near-optimal solutions for two point loads between two supports
    • Abstract: Abstract Extending a previous work, a near-optimal family of solutions for the two-load problem is shown, here restricted to the half plain domain. This family is compared with the benchmarks obtained by Sokół and Lewiński (2011a), resulting the cost only slightly larger than the benchmarks, being its geometry simpler. Results taking into account horizontal forces which can be originated by the friction between foundation and ground or by active applied forces are also shown. Finally, an exploration of layouts resulting for solutions to this problem with few nodes is included.
      PubDate: 2015-06-10
       
  • PolyTop++: an efficient alternative for serial and parallel topology
           optimization on CPUs & GPUs
    • Abstract: Abstract This paper presents the PolyTop++, an efficient and modular framework for parallel structural topology optimization using polygonal meshes. It consists of a C++ and CUDA (a parallel computing model for GPUs) alternative implementations of the PolyTop code by Talischi et al. (Struct Multidiscip Optim 45(3):329–357 2012b). PolyTop++ was designed to support both CPU and GPU parallel solutions. The software takes advantage of the C++ programming language and the CUDA model to design algorithms with efficient memory management, capable of solving large-scale problems, and uses its object-oriented flexibility in order to provide a modular scheme. We describe our implementation of different solvers for the finite element analysis, including both direct and iterative solvers, and an iterative ‘matrix-free’ solver; these were all implemented in serial and parallel modes, including a GPU version. Finally, we present numerical results for problems with about 40 million degrees of freedom both in 2D and 3D.
      PubDate: 2015-06-05
       
  • Managing variable-dimension structural optimization problems using
           generative algorithms
    • Abstract: This article introduces a novel design abstraction concept for efficient truss topology and geometry optimization. The core advancement introduced here is to represent truss topology and geometry using rules of generative algorithms, and to operate on generative algorithm rules using a genetic algorithm rather than directly on the design description. This indirect design representation supports efficient exploration of variable and high-dimension design topologies. Generative design strategies are also independent of any kind of ground structure, thus avoiding the inherent limitations of ground structure approaches that may hinder innovative design solutions by defining a priori what topologies may be considered. We present new generative algorithm strategies that automatically satisfy structural stability constraints, and that can produce truss topologies with a diversity of patterns within an individual truss design. Truss topology and geometry is optimized in an outer-loop by a genetic algorithm that operates on generative algorithm rules, and size optimization is performed in an inner-loop for each candidate topology using sequential linear programming. The proposed methodology supports concurrent optimization of truss topology, geometry, and size. The generative algorithm abstraction layer also supports the design of variable-dimension structures, which can be generated from the same fixed-dimension rule set. Finally, we demonstrate the effectiveness of the new methodology by examining archetypal two- and three-dimensional truss design optimization problems.
      PubDate: 2015-06-03
       
  • Adjoint sensitivity related to geometric parameters for mid-high frequency
           range vibroacoustics
    • Abstract: Abstract Shape optimization issues under vibroacoustic criteria are considered in present paper. The adjoint-based gradient method was developed to minimize the energy density inside a cavity by changing its geometry parameters. The adjoint equations give the sensitivity information, which is subsequently used in a gradient-based minimization of a prescribed cost functional that models the energy density via Simplified Energy Method. Objective function is obtained by mapping 3D cavity surface on a 2D domain with the help of transformation function. Thus, the remeshing of the geometry is avoided and smoothness of the solution is reached. The optimization process is based on adjoint calculation of the gradient that leads to analytical expressions of the directional derivatives without additional computational cost. The proposed method is validated for the case of rectangular cavity modeled with patches of Bezier surfaces.
      PubDate: 2015-06-02
       
  • 3D interactive topology optimization on hand-held devices
    • Abstract: Abstract This educational paper describes the implementation aspects, user interface design considerations and workflow potential of the recently published TopOpt 3D App. The app solves the standard minimum compliance problem in 3D and allows the user to change design settings interactively at any point in time during the optimization. Apart from its educational nature, the app may point towards future ways of performing industrial design. Instead of the usual geometrize, then model and optimize approach, the geometry now automatically adapts to the varying boundary and loading conditions. The app is freely available for iOS at Apple’s App Store and at http://www.topopt.dtu.dk/TopOpt3D for Windows and OSX.
      PubDate: 2015-06-01
       
  • Design optimization of a runflat structure based on multi-objective
           genetic algorithm
    • Abstract: Abstract Runflat structure plays an important role in determining the sustainable mileage after the tire is shot. Lightweight, stiffness and strength are highly relevant to the overall performance of the structure. A parameterized model was built based on the full study of the structure, and a new adaptive meshing method is proposed to ensure the quality of the model. The accuracy of the new model was verified by comparing to the traditional finite element model. The parameter study was carried out to investigate the response of the performance and mass. Multi-objective optimization model was established by applying optimal Latin square design method and response surface model approach. Non-dominated sorting genetic algorithm-II (NSGA-II) was applied to obtain the optimization design. The results indicate that the combination of parameterized model and multi-objective genetic algorithms successfully achieve the goal of multi-objective optimization for mass and displacement while ensuring the stress. Meanwhile, the optimal topology, shape and thickness optimization for the runflat structure have been achieved at the same time.
      PubDate: 2015-06-01
       
 
 
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