Search results for "optimization"
showing 10 items of 2824 documents
Simple Relationships for the Optimal Design of Paired Drip Laterals on Uniform Slopes
2016
Microirrigation plants, if properly designed, allow water use efficiency to be optimized and quite high values of emission uniformity to be obtained in the field. It is known that disposing paired laterals, in which two distribution pipes extend in opposite directions from a common manifold, contribute to increasing water use efficiency. Recently, an analytical procedure has been proposed to optimally design paired drip laterals on uniform slopes under the assumption of neglect: (1) the variations of the emitters’ flow rate along the lateral, and (2) the local losses due to the emitters’ insertions. However, this procedure is not readily usable for every geometric and hydraulic characterist…
3D-2D dimensional reduction for a nonlinear optimal design problem with perimeter penalization
2012
A 3D-2D dimension reduction for a nonlinear optimal design problem with a perimeter penalization is performed in the realm of $\Gamma$-convergence, providing an integral representation for the limit functional.
Crowded comparison operators for constraints handling in NSGA-II for optimal design of the compensation system in electrical distribution networks
2006
This paper proposes an improvement of an efficient multiobjective optimization algorithm, Non-dominated Sorting Genetic Algorithm II, NSGA-II, that has been here applied to solve the problem of optimal capacitors placement in distribution systems. The studied improvement involves the Crowded Comparison Operator and modifies it in order to handle several constraints. The problem of optimal location and sizing of capacitor banks for losses reduction and voltage profile flattening in medium voltage (MV) automated distribution systems is a difficult combinatorial constrained optimization problem which is deeply studied in literature. In this paper, the efficiency of the proposed Crowded Compari…
Optimal Design of Trusses According to a Plastic Shakedown Criterion
2004
The optimal design of elastic-perfectly plastic truss structures subjected to quasi-statically loads variable within a given load domain is studied. The actions are given as the combination of fixed load and perfect cyclic load. Suitably chosen load multipliers are given. A minimum volume formulation of the design problem with assigned limit load multiplier is developed and it is provided on the grounds of a statical approach as well as of a kinematical approach. The incremental collapse (ratchetting) of the optimal structure is prevented, as long as the loads are not greater than some prescribed values, by special constraints suitably introduced in the search problem. The Kuhn-Tucker equat…
A design algorithm for the optimization of laminated composite structures
1999
This paper is devoted to the optimal design of laminated composite structures. The goal of the study is to assess the quality and the performance of an algorithm based on the directional derivative method. Particular attention is paid to the one‐dimensional search, a critical step of the process, performed by cubic splines approximation. The optimization problem is formulated as weight minimization, under constraints on the mechanical behavior of the structure. The assumed design variables are the ply thicknesses, treated as continuous design variables, constrained by technological requirements. The structural analysis is performed making use of quadrilateral four‐node composite elements, b…
Optimization of continuous elastic perfectly plastic beams
2004
Abstract The optimal design of elastic plastic beams subjected to loads quasi-statically variable within a given domain is studied. A minimum volume formulation and a maximum load multiplier formulation are developed, both expressed on the grounds of a statical as well as of a kinematical approach. The search problems are formulated according to three different limiting criteria acting simultaneously. For each criterion a corresponding selected safety factor is imposed. The Euler–Lagrange equations related to the above described problems are deduced. A special iterative technique devoted to the solution of the above referenced problems is proposed. Some numerical examples conclude the paper.
Multiobjective optimization of an ultrasonic transducer using NIMBUS
2005
The optimal design of an ultrasonic transducer is a multiobjective optimization problem since the final outcome needs to satisfy several conflicting criteria. Simulation tools are often used to avoid expensive and time-consuming experiments, but even simulations may be inefficient and lead to inadequate results if they are based only on trial and error. In this work, the interactive multiobjective optimization method NIMBUS is applied in designing a high-power ultrasonic transducer. The performance of the transducer is simulated with a finite element model, and three design goals are formulated as objective functions to be minimized. To find an appropriate compromise solution, additional pr…
Thermal buckling optimization of composite laminates by evolution strategies
2000
Abstract Thermal buckling optimization of laminated composite plates subject to a temperature rise is presented in this paper. Aerospace structures require such components that are able to withstand the external environment loads without loss of stability. The discrete optimal design problem, formulated under strain and ply contiguity constraints is solved using evolution strategies, a guided random-search method. Two different constraint handling methods are investigated and compared: the disregarding infeasible solutions and the classical penalty function approach. The results are also compared with an exact enumerative study conducted on the problem, showing the effectiveness and perform…
Design of concave and convex paired sloped drip laterals
2017
Abstract Properly designed microirrigation plants allow water use efficiency to be optimized and quite high values of emission uniformity to be obtained in the field. Disposing paired laterals so that two distribution pipes extend in opposite directions from a common manifold contributes to provide more uniform pressure to all laterals in thesystem. Towards this end, an analytical procedure to optimize the uniform pressure when designing paired drip laterals on uniform slopes has recently been proposed, based on the assumption that the variations of the emitters’ flow rate along the lateral and the local losses due to the emitters’ insertions could be neglected. More recently, an easy metho…
Optimal design of complex passive-damping systems for vibration control of large structures: An energy-to-peak approach
2014
Published version of an article in the journal: Abstract and Applied Analysis. Also available from the publisher at: http://dx.doi.org/10.1155/2014/510236 Open Access We present a new design strategy that makes it possible to synthesize decentralized output-feedback controllers by solving two successive optimization problems with linear matrix inequality (LMI) constraints. In the initial LMI optimization problem, two auxiliary elements are computed: a standard state-feedback controller, which can be taken as a reference in the performance assessment, and a matrix that facilitates a proper definition of the main LMI optimization problem. Next, by solving the second optimization problem, the …