The Experts below are selected from a list of 180 Experts worldwide ranked by ideXlab platform

Erik Lund - One of the best experts on this subject based on the ideXlab platform.

  • On Discrete Material Optimization of Laminated Composites Using Global and Local Criteria
    Solid Mechanics and Its Applications, 2020
    Co-Authors: Joachim Stegmann, Erik Lund
    Abstract:

    Discrete Material Optimization is introduced as a method for doing Material optimization on general laminated composite shell structures where the objective is to minimize maximum strain values. The method relies on ideas from multiphase topology optimization and uses gradient information in combination with mathematical programming to solve a discrete optimization Problem. The method can be used to solve the orientation Problem of orthotropic Materials and the Material Selection Problem as well as Problems involving both. The method has previously been applied to compliance minimization and its applicability to min-max Problems is demonstrated for two simple examples and the results compared to designs obtained using compliance minimization.

  • discrete Material optimization of general composite shell structures
    International Journal for Numerical Methods in Engineering, 2005
    Co-Authors: Joachim Stegmann, Erik Lund
    Abstract:

    A novel method for doing Material optimization of general composite laminate shell structures is presented and its capabilities are illustrated with three examples. The method is labelled Discrete Material Optimization (DMO) but uses gradient information combined with mathematical programming to solve a discrete optimization Problem. The method can be used to solve the orientation Problem of orthotropic Materials and the Material Selection Problem as well as Problems involving both. The method relies on ideas from multiphase topology optimization to achieve a parametrization which is very general and reduces the risk of obtaining a local optimum solution for the tested configurations. The applicability of the DMO method is demonstrated for fibre angle optimization of a cantilever beam and combined fibre angle and Material Selection optimization of a four-point beam bending Problem and a doubly curved laminated shell. Copyright © 2005 John Wiley & Sons, Ltd.

  • Discrete Material optimization of general composite shell structures
    International Journal for Numerical Methods in Engineering, 2005
    Co-Authors: Joachim Stegmann, Erik Lund
    Abstract:

    A novel method for doing Material optimization of general composite laminate shell structures is presented and its capabilities are illustrated with three examples. The method is labelled Discrete Material Optimization (DMO) but uses gradient information combined with mathematical programming to solve a discrete optimization Problem. The method can be used to solve the orientation Problem of orthotropic Materials and the Material Selection Problem as well as Problems involving both. The method relies on ideas from multiphase topology optimization to achieve a parametrization which is very general and reduces the risk of obtaining a local optimum solution for the tested configurations. The applicability of the DMO method is demonstrated for fibre angle optimization of a cantilever beam and combined fibre angle and Material Selection optimization of a four-point beam bending Problem and a doubly curved laminated shell.

Pierre Duysinx - One of the best experts on this subject based on the ideXlab platform.

  • simultaneous design of structural layout and discrete fiber orientation using bi value coding parameterization and volume constraint
    Structural and Multidisciplinary Optimization, 2013
    Co-Authors: Weihong Zhang, Pierre Duysinx
    Abstract:

    The so-called bi-value coding parameterization (BCP) method is developed for the simultaneous optimization of layout design and discrete fiber orientations of laminated structures related to the compliance minimization and natural frequency maximization. Both kinds of Problems are transformed into a discrete Material Selection Problem that is then solved as a continuous topology optimization Problem with multiphase Materials. A new form of the volume constraint is introduced in accordance with the BCP to control the Material usage and Material removal in the corresponding Problem formulation. The BCP scheme assigning the integer value of +1 or -1 to each design variable for the unique "coding" is efficiently used to interpolate discrete fiber orientations and to identify the presence and removal of Materials. Meanwhile, a general set-up strategy is proposed by assigning "uniform" weight values in BCP to ensure the feasibility of the initial starting point. Numerical tests illustrate that the BCP is efficient in dealing with both kinds of design Problems including the volume constraint.

  • a bi value coding parameterization scheme for the discrete optimal orientation design of the composite laminate
    International Journal for Numerical Methods in Engineering, 2012
    Co-Authors: Weihong Zhang, Pierre Duysinx
    Abstract:

    SUMMARY The discrete optimal orientation design of the composite laminate can be treated as a Material Selection Problem dealt with by using the concept of continuous topology optimization method. In this work, a new bi-value coding parameterization (BCP) scheme of closed form is proposed to this aim. The basic idea of the BCP scheme is to ‘code’ each Material phase using integer values of +1 and –1 so that each available Material phase has one unique ‘code’ consisting of +1 and/or –1 assigned to design variables. Theoretical and numerical comparisons between the proposed BCP scheme and existing schemes show that the BCP has the advantage of an evident reduction of the number of design variables in logarithmic form. The benefit is particularly remarkable when the number of candidate Materials becomes important in large-scale Problems. Numerical tests with up to 36 candidate Material orientations are illustrated for the first time to indicate the reliability and efficiency of the BCP scheme in solving this kind of Problem. It proves that the BCP is an interesting and valuable scheme to achieve the optimal orientations for large-scale design Problems. Besides, a four-layer laminate example is tested to demonstrate that the proposed BCP scheme can easily be extended to multilayer Problems. Copyright © 2012 John Wiley & Sons, Ltd.

  • new developments for an efficient solution of the discrete Material topology optimization of composite structures
    2011
    Co-Authors: Pierre Duysinx, Weihong Zhang, Claude Fleury, Michael Bruyneel
    Abstract:

    Optimal design of composite structures can be formulated as an optimal Selection of Material in a list of different laminates. Based on the seminal work by Stegmann and Lund (2005), the optimal Problem can be stated as a topology optimization Problem with multiple Materials. The research work carries out a large investigation of different interpolation and penalization schemes for the optimal Material Selection Problem. Besides the classical Design Material Optimization (DMO) scheme and the recent Shape Function with Penalization (SFP) scheme by Bruyneel (2011), the research introduces a generalization of the SFP approach using a bi-value coding parameterization (BCP) (Gao, Zhang, and Duysinx, 2011) The paper provides a comparison of the different parameterization approaches. It also proposes alternative penalization schemes and it investigates the effect of the power penalization. Finally, we discuss the solution aspects in the perspective of solving large-scale industrial applications. The conclusions are illustrated by a numerical application for the compliance maximization of an inplane composite ply.

Lian Wu Yang - One of the best experts on this subject based on the ideXlab platform.

  • a novel method combining grey target decision model with close value for Material Selection Problem
    Advanced Materials Research, 2014
    Co-Authors: Lian Wu Yang, Shi Gang Chao
    Abstract:

    Aiming at the Material Selection Problem, a new Selection method is proposed combining the multi-target grey target decision model with close value method. The new method can reflect the alternative is close to the bull's-eye and away from the close value minus the bull 's-eye, which overcomes the traditional grey target decision model of sorting scheme only consider is distance to target's influence on the decisions without considering the negative distance to target. And the variation coefficient method is used to objectively determine the index weight, avoid the arbitrariness of previous subjective weight determination. Finally, the practical example of a Material Selection Problem is given to illustrate the practicability and effectiveness of the decision making process.

  • improved copras method and application in Material Selection Problem
    Applied Mechanics and Materials, 2014
    Co-Authors: Lian Wu Yang
    Abstract:

    The aim of this paper is to put forward a new Material Selection method based on COPRAS method. The method combines the COPRAS method and coefficient of variation method. The new method is simple and easy to use, and coefficient of variation method can objectively determine the attributes weights. Thus it can be easily accepted by decision makers. Finally, a practical example is used to demonstrate the feasibility and effectiveness of the proposed method.

  • projection method for Material Selection Problem with triangular fuzzy numbers
    Advanced Materials Research, 2014
    Co-Authors: Lian Wu Yang, Shi Xiao Xiao, Shao Liang Yuan
    Abstract:

    The aim of this paper is to develop a new method for the Material Selection Problem, which is important for the product design. Material Selection Problem is actually a multi-attribute decision making (MADM) Problem which contains many influence factors. The new Material Selection method is an extension of projection method with evaluation attribution values expressed with triangular fuzzy numbers. Coefficient of variation method is used to determine weights of evaluation attribute. A grinding wheel abrasive Material Selection Problem is used to illustrate the effectiveness and practicability of the proposed method.

  • projection method for Material Selection Problem with interval numbers
    Advanced Materials Research, 2014
    Co-Authors: Lian Wu Yang
    Abstract:

    Material Selection Problem is important for the product design, and contains many influence factors. Thus it is actually a multi-attribute decision making (MADM) Problems. The aim of this paper is to propose a new decision method based on the projection method for the Material Selection Problem, in which attribute values expressed with interval numbers. An objective determining weights method is proposed according to coefficient of variation method. A practical example is used to illustrate the effectiveness and practicability of the proposed method.

  • grey relation analysis method for Material Selection Problem with interval numbers
    Advanced Materials Research, 2014
    Co-Authors: Lian Wu Yang
    Abstract:

    Material Selection is an important step in the product design process. Material Selection Problem contains many influence factors, and thus it is actually a multi-attribute decision making Problem. In some situations, measure values cannot or unsuitable to be depicted by crisp numbers. Interval number is a suitable Selection in these situations, and for the Material Selection Problem with interval numbers, a new decision making method is developed based on grey relation analysis method. The attribute weights will be determined by the coefficient of variation method. Finally, a practical example is used to illustrate the effectiveness and feasibility of the proposed method.

Joachim Stegmann - One of the best experts on this subject based on the ideXlab platform.

  • On Discrete Material Optimization of Laminated Composites Using Global and Local Criteria
    Solid Mechanics and Its Applications, 2020
    Co-Authors: Joachim Stegmann, Erik Lund
    Abstract:

    Discrete Material Optimization is introduced as a method for doing Material optimization on general laminated composite shell structures where the objective is to minimize maximum strain values. The method relies on ideas from multiphase topology optimization and uses gradient information in combination with mathematical programming to solve a discrete optimization Problem. The method can be used to solve the orientation Problem of orthotropic Materials and the Material Selection Problem as well as Problems involving both. The method has previously been applied to compliance minimization and its applicability to min-max Problems is demonstrated for two simple examples and the results compared to designs obtained using compliance minimization.

  • discrete Material optimization of general composite shell structures
    International Journal for Numerical Methods in Engineering, 2005
    Co-Authors: Joachim Stegmann, Erik Lund
    Abstract:

    A novel method for doing Material optimization of general composite laminate shell structures is presented and its capabilities are illustrated with three examples. The method is labelled Discrete Material Optimization (DMO) but uses gradient information combined with mathematical programming to solve a discrete optimization Problem. The method can be used to solve the orientation Problem of orthotropic Materials and the Material Selection Problem as well as Problems involving both. The method relies on ideas from multiphase topology optimization to achieve a parametrization which is very general and reduces the risk of obtaining a local optimum solution for the tested configurations. The applicability of the DMO method is demonstrated for fibre angle optimization of a cantilever beam and combined fibre angle and Material Selection optimization of a four-point beam bending Problem and a doubly curved laminated shell. Copyright © 2005 John Wiley & Sons, Ltd.

  • Discrete Material optimization of general composite shell structures
    International Journal for Numerical Methods in Engineering, 2005
    Co-Authors: Joachim Stegmann, Erik Lund
    Abstract:

    A novel method for doing Material optimization of general composite laminate shell structures is presented and its capabilities are illustrated with three examples. The method is labelled Discrete Material Optimization (DMO) but uses gradient information combined with mathematical programming to solve a discrete optimization Problem. The method can be used to solve the orientation Problem of orthotropic Materials and the Material Selection Problem as well as Problems involving both. The method relies on ideas from multiphase topology optimization to achieve a parametrization which is very general and reduces the risk of obtaining a local optimum solution for the tested configurations. The applicability of the DMO method is demonstrated for fibre angle optimization of a cantilever beam and combined fibre angle and Material Selection optimization of a four-point beam bending Problem and a doubly curved laminated shell.

Ali Shanian - One of the best experts on this subject based on the ideXlab platform.

  • A methodological concept for Material Selection of highly sensitive components based on multiple criteria decision analysis
    Expert Systems With Applications, 2009
    Co-Authors: Ali Shanian, Oumarou Savadogo
    Abstract:

    Material Selection of highly sensitive components is one of the most challenging issues in the design and development of structural elements in aerospace and nuclear industry. This work compares some of the most widely potential multi-criteria decision making models for addressing all the stages in solving a Material Selection Problem of highly sensitive components involving conflicting as well as multiple design objectives. For the first step, the compensatory models are discussed and employed to solve a multi-criteria Material Selection for a thermal loaded conductor in the presence of its required multi-functional characteristics. For the next step, using different versions of the non-compensatory methods examine the outranking approach to solve the same Problem. The results are compared to each other to verify the effect of compensations and non-compensations in the methods and their sensitivity to ranking stability. It is of particular interest to see how different approaches of the Multiple Attribute Decision Making (MADM) models differ from each other when criterion of cost is a critical factor in the Problem. The effect of individual attributes of cost criterion has been studied to ensure the reliability of the chosen candidate Material by MADM models.

  • topsis multiple criteria decision support analysis for Material Selection of metallic bipolar plates for polymer electrolyte fuel cell
    Journal of Power Sources, 2006
    Co-Authors: Ali Shanian, O Savadogo
    Abstract:

    Several kinds of metallic bipolar plates for PEMFCs are currently being developed in order to meet the demands of cost reduction, stack volume, lower weight and enhanced power density. This work shows an application of the Technique of ranking Preferences by Similarity to the Ideal Solution (TOPSIS) Multiple Attribute Decision Making (MADM) method for solving the Material Selection Problem of metallic bipolar plates for polymer electrolyte fuel cell (PEFC), which often involves multiple and conflicting objectives. The proposed methodological tool can aid the Material designer in the modeling and Selection of suitable Materials according to a set of predefined criteria. After introducing the theoretical background, a case study is presented for the Material Selection of a bipolar plate in a PEFC. A list of all possible choices, from the best to the worst Materials, is obtained by taking into account all the Material Selection criteria, including the cost of production. A user-defined code in Mathematica has been developed to facilitate the implementation of the method. It was shown that the optimum value of each criterion is independent of other criteria values (i.e., no interaction is allowed). The proposed approach may be applied to other Problems of Material Selection of fuel cell components.

  • Gear Material Selection with uncertain and incomplete data. Material performance indices and decision aid model
    International Journal of Mechanics and Materials in Design, 2006
    Co-Authors: A. S. Milani, Ali Shanian
    Abstract:

    First, a set of major gear design criteria are used to develop six Material performance indices for Material Selection purposes. They are, a surface fatigue limit index, a surface fatigue lifetime index, a bending fatigue limit index, a bending fatigue lifetime index, an abrasive wear index, and a machinability index. A modified decision matrix in the presence of data uncertainties and incompleteness is then proposed to show the effect of the developed indices. It is shown that using individual Material properties and approximations among them may not satisfy specific design goals for a specific application. Next, the ELECTRE III multiple criteria decision aid (MCDA) model is applied to rank the best compromised candidate Materials, while considering criteria tradeoffs, designers’ preference information, data uncertainties and incompleteness. An effort is made to reconcile mathematically motivated model thresholds (namely, the indifference, strict preference, and veto thresholds) with experimentally motivated characteristics such as upper and lower limits of measured Material properties. It is shown that the proposed multi-criteria approach may also be useful in revealing incomparable and/or indifferent alternatives that would not be distinguishable otherwise. To ensure rank stability of the chosen Materials, the effect of potential uncertainties in designers’ opinions during criteria weighting is introduced by means of a dilation and concentration sensitivity analysis process. The main originality lies in resolving a non-compensatory, application-specific, and uncertainty-based multiple criteria Material Selection Problem in gear design optimization.