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  Subjects -> ENGINEERING (Total: 2244 journals)
    - CHEMICAL ENGINEERING (187 journals)
    - CIVIL ENGINEERING (179 journals)
    - ELECTRICAL ENGINEERING (97 journals)
    - ENGINEERING (1205 journals)
    - ENGINEERING MECHANICS AND MATERIALS (375 journals)
    - HYDRAULIC ENGINEERING (53 journals)
    - INDUSTRIAL ENGINEERING (61 journals)
    - MECHANICAL ENGINEERING (87 journals)

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: 26)
Advances in Structural Engineering     Full-text available via subscription   (Followers: 15)
Ambiente Construído     Open Access   (Followers: 1)
American Journal of Civil Engineering and Architecture     Open Access   (Followers: 21)
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: 5)
Case Studies in Nondestructive Testing and Evaluation     Open Access   (Followers: 3)
Case Studies in Structural Engineering     Open Access   (Followers: 1)
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: 4)
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: 8)
Computers & Structures     Hybrid Journal   (Followers: 25)
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  
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  
Geotechnik     Hybrid Journal   (Followers: 1)
Géotechnique Letters     Hybrid Journal   (Followers: 3)
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: 7)
International Journal of Concrete Structures and Materials     Open Access   (Followers: 6)
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: 1)
International Journal of Masonry Research and Innovation     Hybrid Journal  
International Journal of Pavement Research and Technology     Open Access   (Followers: 1)
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: 3)
Journal of Accessibility and Design for All     Open Access   (Followers: 6)
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  
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: 68)
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: 1)
Journal of Fluids and Structures     Hybrid Journal   (Followers: 4)
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: 8)
Journal of Infrastructure Systems     Full-text available via subscription   (Followers: 15)
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: 2)
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: 3)
Journal of Pipeline Systems Engineering and Practice     Full-text available via subscription   (Followers: 6)
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: 35)
Journal of Structural Fire Engineering     Full-text available via subscription   (Followers: 6)
Journal of Structures     Open Access   (Followers: 2)
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: 6)
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  
Steel Construction - Design and Research     Hybrid Journal   (Followers: 1)
Structural and Multidisciplinary Optimization     Hybrid Journal   (Followers: 7)
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: 1)
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: 6)
Water Science & Technology     Partially Free   (Followers: 20)
Water Science and Technology : Water Supply     Partially Free   (Followers: 21)

           

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  [2281 journals]
  • Optimization of excess system capability for increased evolvability
    • Abstract: Abstract System evolvability is vital to the longevity of large-scale complex engineered systems. The need for evolvability in complex systems is a result of their long service lives, rapid advances to their integrated technologies, unforeseen operating conditions, and emerging system requirements. Building excess capability into complex systems can improve their ability to evolve while in service. However, excess capability increases initial build cost and operating cost, which is compounded across the service life of the system. Excess capability that is eventually used adds benefit by allowing for in-service evolution to meet emerging system requirements. Therefore, there is a trade-off between the cost of excess capability initially built into the system and the benefit that is added to the system by enabling future evolution. This paper introduces a process for optimizing the amount of excess capability in a complex system. This process results in a set of evolvable systems without excessive cost. We demonstrate how this process can be used to select the amount of excess capability that should be included in a military ground vehicle.
      PubDate: 2016-06-01
       
  • A concurrent subspace collaborative optimization architecture to
           structural synthetical optimization design
    • Abstract: Abstract A concurrent subspace collaborative optimization (CSCO) technique is developed in this paper to deal with the layout, shape and size optimization of the hierarchical feature structures. The structural optimization is divided into three concurrent subspaces: the structural layout optimization, shape optimization and size optimization. And all these subspace optimizations are solved independently in every iteration loop. Based on the optimal results of each subspace, the design variables are synthetically adjusted at the end of the loop. The iteration loop will be repeated until the convergence accuracy requirement is met. Two structural optimization examples, including truss structure and composite stiffened panel, are completed in this paper. The results obtained from them demonstrate the reasonability and effectiveness of the CSCO technique.
      PubDate: 2016-06-01
       
  • A sequential sampling strategy to improve the global fidelity of
           metamodels in multi-level system design
    • Abstract: Abstract In engineering design, complex systems that involve a multitude of decision variables and parameters are often decomposed into several submodels (also called subsystems and/or components) with a hierarchical (multi-level) manner to manage complexity. Metamodeling techniques are widely used to replace the original time-consuming computer simulation models to further reduce computational burden in multi-level system performance analysis and design optimization. However, due to the limited samples from simulation models, metamodels may contain metamodeling uncertainties at un-sampled sites. Such metamodeling uncertainties arising from metamodels across the entire hierarchy will propagate from the lower to upper levels and eventually impact the top-level response of interest. With the aim of improving the global fidelity of metamodels for multi-level system performance analysis and design optimization, a new sequential sampling strategy is proposed in this paper. The proposed method contains two basic elements: (1) quantifying metamodeling uncertainty propagated from the lower-level metamodels to the top-level response of interest and (2) seeking a new sample site at which the global fidelity of the multi-level system model can be maximally improved. As exemplified by the two numerical examples and a multi-scale bracket structure example, with the same amount of samples from computer simulation models, the new sequential sampling strategy is superior to existing sequential sampling strategies in terms of improving the global fidelity of the metamodels of multi-level systems.
      PubDate: 2016-06-01
       
  • Topology optimization: a review for structural designs under vibration
           problems
    • Abstract: Abstract This article provides a comprehensive review of structural optimization employing topology methods for structures under vibration problems. Topology optimization allows creative and radical design modifications, compared to shape and size optimization techniques. Various works of structural topology optimization, which are subjected to vibration as the response function of the optimization process, are reviewed. Different types of calculus and numerical methods commonly used for solving structural topological optimization problems are briefly discussed. Moreover, different aspects of topology optimization related to vibration problems are explained. The articles reviewed are largely confined to linear systems that concern small vibration amplitudes. Accordingly, the works related to vibration topological optimization are classified according to the method employed (homogenization, evolutionary structural optimization, solid isotropic material with penalization, or level set). The reviewed works are tabulated according to their methodology, year, and the objective functions and applications of each work. Although the homogenization and evolutionary methods were common in the past, the solid isotropic material with penalization (SIMP) method is the most popular method applied in recent years. The advantages of the level set method show promise for future applications.
      PubDate: 2016-06-01
       
  • Free material optimization for laminated plates and shells
    • Abstract: Abstract Free Material Optimization (FMO) is a powerful approach for conceptual optimal design of composite structures. The design variable in FMO is the entire elastic material tensor which is allowed to vary almost freely over the design domain. The imposed requirements on the tensor are that it is symmetric and positive semidefinite. Most of today’s studies on FMO focus on models for two- and three-dimensional structures. The objective of this article is to extend existing FMO models and methods to laminated plate and shell structures, which are used in many engineering applications. In FMO, the resulting optimization problem is generally a non convex semidefinite program with many matrix inequalities which requires special-purpose optimization methods. The FMO problems are efficiently solved by a primal-dual interior point method developed and implemented by the authors. The quality of the proposed FMO models and the method are supported by several large-scale numerical experiments.
      PubDate: 2016-06-01
       
  • Topology optimization of PCLD on plates for minimizing sound radiation at
           low frequency resonance
    • Abstract: Abstract Topology optimization of passive constrained layer damping (PCLD) treatment patched on thin plates with respect to sound radiation at low frequency resonance is investigated. An extended solid isotropic material with penalization (SIMP) model is described using an interface finite element model for viscoelastic layer. Then the given FE mesh for base structure can remain the same during the optimization process. The objective function, radiated sound power, is simplified by using sound radiation mode and modal strain energy method, the merit of which is the complex dynamic equations of the composite plate need not to be solved and only modal analyses for the associated undamped modal equations are required. Numerical and experimental results show that significant reductions of the sound power are achieved. Two optimal topologies of the PCLD patches are analyzed. It’s shown that to minimize the sound radiation power at low frequency, not only the structural damping but also the volume velocity should be concerned.
      PubDate: 2016-06-01
       
  • Structural optimization methods of nonlinear static analysis with contact
           and its application to design lightweight gear box of automatic
           transmission of vehicles
    • Abstract: Abstract In this paper, we consider lightweight design methods for gear box of automatic transmission of vehicles with contact constraints. Lightweight design is a fundamental requirement for protecting the environment and improving fuel economy. In addition, durability is another important requirement for safe driving. However, in the design of automatic transmissions, these two requirements are usually in a trade-off relationship and engineers spend a long design study time. This paper deals with design approaches using structural optimization method to design lightweight structures and to minimize stress with contact constraints. Stress with contact constraints is solved using the finite element method. Three different structural optimization methods, topometry, topography and freeform optimization, are applied for the design of a lightweight gear box of an automatic transmission. The optimization results show that the optimization methods successfully found the lightweight gear box design and can be used at the early stage of the design process of automatic transmissions.
      PubDate: 2016-06-01
       
  • Thickness control in structural optimization via a level set method
    • Abstract: Abstract In the context of structural optimization via a level-set method we propose a framework to handle geometric constraints related to a notion of local thickness. The local thickness is calculated using the signed distance function to the shape. We formulate global constraints using integral functionals and compute their shape derivatives. We discuss different strategies and possible approximations to handle the geometric constraints. We implement our approach in two and three space dimensions for a model of linearized elasticity. As can be expected, the resulting optimized shapes are strongly dependent on the initial guesses and on the specific treatment of the constraints since, in particular, some topological changes may be prevented by those constraints.
      PubDate: 2016-06-01
       
  • A new topology optimization approach based on Moving Morphable Components
           (MMC) and the ersatz material model
    • Abstract: Abstract This paper presents a new topology optimization approach based on the so-called Moving Morphable Components (MMC) solution framework. The proposed method improves several weaknesses of the previous approach (e.g., Guo et al. in J Appl Mech 81:081009, 2014a) in the sense that it can not only allow for components with variable thicknesses but also enhance the numerical solution efficiency substantially. This is achieved by constructing the topological description functions of the components appropriately, and utilizing the ersatz material model through projecting the topological description functions of the components. Numerical examples demonstrate the effectiveness of the proposed approach. In order to help readers understand the essential features of this approach, a 188 line Matlab implementation of this approach is also provided.
      PubDate: 2016-06-01
       
  • An enhanced RBF-HDMR integrated with an adaptive sampling method for
           approximating high dimensional problems in engineering design
    • Abstract: Abstract Metamodels are often used in engineering design optimization problems with expensive simulations to save computational cost. But these metamodels often face “curse-of-dimensionality” when used in approximating high dimensional problems. Therefore, a new high dimensional model representation (HDMR) by combining Cut-HDMR with an enhanced RBF based on ensemble model is proposed. The developed HDMR, termed as ERBF-HDMR, sufficiently utilizes advantages of RBF and ensemble model in the modeling process. It can naturally explore and exploit the linearity/nonlinearity and correlations among variables of underlying problems, which are unknown or computationally expensive. Besides, to improve the efficiency of the ERBF-HDMR, an adaptive sampling method is proposed to add new sample points. Moreover, a mathematical function is used to illustrate the modeling principles and procedures of the adaptive ERBF-HDMR. And a comprehensive comparison between the adaptive ERBF-HDMR and other different Cut-HDMRs in literature has been made on eleven numerical examples with a wide scope of dimensionalities to show the prediction ability of different HDMRs. Finally, the proposed HDMR is used in the structural design optimization of the bearings of an all-direction propeller with the aim of reducing vibration.
      PubDate: 2016-06-01
       
  • An efficient second-order SQP method for structural topology optimization
    • Abstract: Abstract This article presents a Sequential Quadratic Programming (SQP) solver for structural topology optimization problems named TopSQP. The implementation is based on the general SQP method proposed in Morales et al. J Numer Anal 32(2):553–579 (2010) called SQP+. The topology optimization problem is modelled using a density approach and thus, is classified as a nonconvex problem. More specifically, the SQP method is designed for the classical minimum compliance problem with a constraint on the volume of the structure. The sub-problems are defined using second-order information. They are reformulated using the specific mathematical properties of the problem to significantly improve the efficiency of the solver. The performance of the TopSQP solver is compared to the special-purpose structural optimization method, the Globally Convergent Method of Moving Asymptotes (GCMMA) and the two general nonlinear solvers IPOPT and SNOPT. Numerical experiments on a large set of benchmark problems show good performance of TopSQP in terms of number of function evaluations. In addition, the use of second-order information helps to decrease the objective function value.
      PubDate: 2016-06-01
       
  • TIMP method for topology optimization of plate structures with
           displacement constraints under multiple loading cases
    • Abstract: Abstract This paper utilizes the TIMP (Transplanting ICM Ideas into Material with Penalization) method to solve topology optimization problems of plate structures with displacement constraints under multiple loading cases. Two basic perspectives embedded within the TIMP method are that, (1) one more penalty function is added besides the Young’s modulus penalty function by transplanting the ICM ideas and progresses into the SIMP (Solid Isotropic Material with Penalization) method, and (2) the definition of the artificial material design variables, as well as the idea of penalization on materials, is inherited from the SIMP method. Based on the TIMP method, complex topology optimization problems with displacement constraints are expressed explicitly by using the element weight and Young’s modulus penalty functions, and the nonlinear programming algorithm is used to get solutions. Displacement filtering is employed to eliminate the mesh-dependency and checkerboard issues, and the coarse selection of quasi-active constraint strategy is adopted to select active constraints and improve the computing efficiency. The whole solution development process is implemented into a secondary development software based on the Abaqus software by its script language Python. Two problems with a single loading case and two problems with multiple loading cases are addressed on this secondary development software. The effects of using linear and nonlinear element weight penalty functions on the convergence speed are observed through these numerical problems. The results demonstrate that the TIMP method is effective to undertake complex topology optimization problems with displacement constraints under multiple loading cases.
      PubDate: 2016-06-01
       
  • A goal-programming enhanced collaborative optimization approach to
           reducing lifecyle costs for naval vessels
    • Abstract: Abstract Understanding the trade-offs involved in assessing lifetime cost for engineering systems requires understanding trends in various engineering disciplines that require significantly different analysis methods to efficiently explore. The corresponding design spaces can be flat, defined by weak minima, and thus difficult to understand using traditixonal optimization methods. This paper presents a new multi-disciplinary framework that uses a goal-programming enhanced multi-objective collaborative optimization (eMOCO) approach to facilitate the development of the spaces. In order to further increase its efficiency in discrete or flat spaces well-suited to evolutionary optimization a unique discipline level genetic algorithm is proposed. Naval vessels are an example of an engineering system that has a difficult design space with respect to lifetime cost, however, one where it is critical to understand. As these costs are increasing, they are becoming limiting factors in a vessel’s operational life. Though they are so important, the interaction between different cost categories such as production and operation has not been explored in depth and is not always clear. Understanding the trade-offs between different aspects of a vessel’s total ownership costs early in the design stage can aid in the production of new ships where they are minimized. The proposed framework is verified on mathematical problems, and then used to develop trade-spaces between resistance and production for a nominal naval combatant vessel. These trade-spaces show both the knowledge gained by designers in understanding these trade-offs and the ability of the proposed eMOCO framework to develop them effectively.
      PubDate: 2016-06-01
       
  • Decomposition analysis of the multidisciplinary coupling in LED
           System-in-Package design using a DSM and a specification language
    • Abstract: Abstract LED System-in-Package (SiP) aims to reduce manufacturing and material costs of LED lighting products through integration of components into one single package, based on semiconductor technology. This introduces multidisciplinary coupling in the system behavior which requires reconsideration of the existing LED design decomposition practice. This paper presents our method to do a decomposition analysis of the multidisciplinary coupling structure for an industry scale LED SiP design problem. The innovative aspect of our method is the use of a specification language to specify the input-output (binary) relationships between design variables, behavioral responses, objective and constraint responses. A design structure matrix, representing the mutual linkage, is automatically generated from the specification. The rows and columns of the DSM are subsequently re-ordered using partitioning and sequencing algorithms to provide insight in the coupling structure. The method is illustrated by means of a simplified example. Subsequently, the results for a recently manufactured LED SiP design prototype are presented.
      PubDate: 2016-06-01
       
  • Analytical solutions for two-bar structures under loads along uncertain
           direction
    • Abstract: Abstract Two-bar structures under uncertain load are optimized analytically. The magnitudes of load are given and their directions are uncertain. The uncertain loads may be along any directions or in a certain range. The optimization problem of least weight structures with stress constraint and minimal compliance structures with prescribed material volume are studied. The most unfavorable directions of load are found. These examples may be used as benchmarks.
      PubDate: 2016-06-01
       
  • Optimum design of laminated composite plates containing a quasi-square
           cutout
    • Abstract: Abstract In this paper, an attempt has been made to calculate the optimal values of effective parameters on the stress distribution around a quasi-square cutout using different optimization algorithms such as Particle Swarm Optimization (PSO), Genetic Algorithm (GA) and Ant Colony Optimization (ACO). To achieve this goal, the analytical results of symmetric laminated composite plates containing a square cutout have been used. The analytical solution can be achieved with the development of the Lekhnitskii solution method. This method is based on using complex variable method in the analysis of two-dimensional problems. In order to use the method in stress analysis of laminates containing a square cutout, by using conformal mapping, the area outside the square cutout is mapped to the area outside of a unit circle. Effective parameters on stress distribution around the square cutout in symmetric laminated plates considered as design variables include: load angle, cutout orientation, bluntness and the stacking sequence of the laminate. Cost function in this problem is the maximum stress created around the cutout calculated by the analytical solution method. Another goal of this paper is to investigate the performance of aforementioned optimization algorithms. The results show that the PSO algorithm converges earlier than the other two methods and have the better cost function.
      PubDate: 2016-05-17
       
  • Finite element model updating of honeycomb sandwich plates using a
           response surface model and global optimization technique
    • Abstract: Abstract Honeycomb sandwich plates are used widely in the aerospace industry. Building accurate finite element models of honeycomb sandwich plates is necessary for analyzing and optimizing the microvibration that occurs in spacecraft. This study investigated two types of finite element dynamic models of honeycomb plates: a sandwich shell model and a shell-volume-shell model. Two response surface model-based optimization methods and a particle swarm optimization method were compared for updating the finite element models. Finally, we validated the accuracy of the two optimized honeycomb sandwich plate finite element dynamic models by comparing the results obtained by the frequency response functions with experimental data.
      PubDate: 2016-05-16
       
  • An immersed boundary approach for shape and topology optimization of
           stationary fluid-structure interaction problems
    • Abstract: Abstract This paper presents an approach to shape and topology optimization of fluid-structure interaction (FSI) problems at steady state. The overall approach builds on an immersed boundary method that couples a Lagrangian formulation of the structure to an Eulerian fluid model, discretized on a deforming mesh. The geometry of the fluid-structure boundary is manipulated by varying the nodal parameters of a discretized level set field. This approach allows for topological changes of the fluid-structure interface, but free-floating volumes of solid material can emerge in the course of the optimization process. The free-floating volumes are tracked and modeled as fluid in the FSI analysis. To sense the isolated solid volumes, an indicator field described by linear, isotropic diffusion is computed prior to analyzing the FSI response of a design. The fluid is modeled with the incompressible Navier-Stokes equations, and the structure is assumed linear elastic. The FSI model is discretized by an extended finite element method, and the fluid-structure coupling conditions are enforced weakly. The resulting nonlinear system of equations is solved monolithically with Newton’s method. The design sensitivities are computed by the adjoint method and the optimization problem is solved by a gradient-based algorithm. The characteristics of this optimization framework are studied with two-dimensional problems at steady state. Numerical results indicate that the proposed treatment of free-floating volumes introduces a discontinuity in the design evolution, yet the method is still successful in converging to meaningful designs.
      PubDate: 2016-05-16
       
  • A new distribution metric for comparing Pareto optimal solutions
    • Abstract: Abstract Evolutionary multi-objective optimization has established itself a core field of research and application, with a proliferation of algorithms derived. During the multi-objective optimization processes, the discovered ideal solutions should be diversely distributed at the Pareto front. In order to measure and compare the performances of different multi-objective evolutionary algorithms, or provide a guidance for the search or a stopping criterion, various performance metrics are defined and used. In this paper, two of the most commonly used metrics, the spacing metric and the overall Pareto spread metric, which evaluate the uniformity and the range of the Pareto solutions’ distribution are studied, respectively. A new distribution metric which potentially can combine these two metrics and resolve their deficiencies for comparing Pareto optimal solutions is then proposed. Five typical Pareto fronts and a real practical example are used to demonstrate the effectiveness of the proposed metric by comparing with the subject matter experts’ ratings.
      PubDate: 2016-05-14
       
  • Obtaining a hyperelastic non-linear orthotropic material model via inverse
           bubble inflation analysis
    • Abstract: Abstract An inverse bubble inflation test is proposed utilizing full displacement field matching to obtain non-linear material models suitable for the Finite Element (FE) method. In this paper a known non-linear orthotropic material model is assumed as the solution for the inverse method to illustrate the process. A bubble inflation FE analysis is performed with the known material model to determine the load and displacement field from the assumed material. Polynomial surfaces are fit to the nodal displacement values of the FE model, such that the entire displacement field is stored as three unique polynomial surfaces. An error formulation was established to quantify the quality of fit between different bubble inflation displacement fields. Gradient based optimization is used to obtain the assumed material model by matching the full displacement field. The inverse bubble inflation test successful produces a non-linear orthotropic model that is analogous to the assumed non-linear orthotropic material, and thus demonstrates that the inverse bubble inflation analysis would be able to characterize other non-linear orthotropic materials.
      PubDate: 2016-05-14
       
 
 
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