scholarly journals An unconstrained minimization technique using successive implementations of Golden Search algorithm

2019 ◽  
Author(s):  
Pamela Kim Salonga ◽  
Jose Marie Inaudito ◽  
Renier Mendoza
Keyword(s):  
Search Algorithm ◽  
Unconstrained Minimization ◽  
Minimization Technique

Optimal Thermal Design of Fin-and-Tube Heat Exchangers by Integration of a SUMT and a SCGM

2016 ◽  
Author(s):  
Xinyi Li ◽  
Ting Ma ◽  
Qiuwang Wang
Keyword(s):  
Heat Exchangers ◽  
Optimization Technique ◽  
Unconstrained Minimization ◽  
Geometric Parameters ◽  
Thermal Design ◽  
Trial And Error ◽  
Heat Transfer Area ◽  
Compact Heat Exchangers ◽  
Minimization Technique ◽  
Combined Structure

It is a recognized hard task for the traditional thermal design of compact heat exchangers to obtain the optimal geometric parameters efficiently and effectively, owing to its complex trial-and-error process. In response to this issue, a simplified conjugate-gradient method (SCGM) combined with a sequential unconstrained minimization technique (SUMT) as a favorable optimization technique is incorporated with the traditional thermal design in this study, and then the key geometric parameters of fin-and-tube heat exchangers (FTHEs) are investigated and optimized successfully. In this method, the minimum total weight of FTHEs as the final objective is discussed, involving two geometric parameters, diameter of tube and height of shape as search variables. Aiming to minimize the objective function, SCGM is introduced to the SUMT to update the search variables continually with the fixed search steps and the search directions. Meanwhile, with the known geometric parameters from the SUMT, the log-mean temperature difference method (LMTD) is applied to determine the heat transfer area under the combined structure sizes for a given heat duty. Additionally, optimization results for three different heat duty is discussed in this work. The results show that it is effective to obtain the optimal sets of geometric parameters of FTHEs by the present method, and there are some guidance values for the thermal designs of compact heat exchangers.

Reliability Based Optimization of Submarine Pressure Hulls With Inelastic Interstiffener Buckling Failure

2006 ◽  
Author(s):  
P. Radha ◽  
K. Rajagopalan
Keyword(s):  
Unconstrained Minimization ◽  
Computer Code ◽  
Correction Method ◽  
Penalty Function Method ◽  
Simulation Design ◽  
Design Variables ◽  
Minimization Technique ◽  
Buckling Failure ◽  
Optimal Values ◽  
Reliability Based Optimization

Uncertainties that exist in modelling and simulation, design variables and parameters, manufacturing processes etc., may lead to large variations in the performance characteristics of the system. Optimized deterministic designs determined without considering uncertainties can be unreliable and may lead to catastrophic failure of the structure being designed. Reliability based optimization (RBO) is a methodology that addresses these problems. In this paper the reliability based optimization of submarine pressure hulls in which the failure gets governed by inelastic interstiffener buckling has been described. The problem has been formulated to minimize the ratio of weight of shell-stiffener geometry to the weight of liquid displaced, subjected to reliability based inelastic interstiffener buckling constraint. Since the methods of analysis of inelastic buckling failure of submarine pressure hulls are inadequate, in the present study the Johnson-Ostenfeld inelastic correction method has been adopted for formulating the constraint. By considering spacing of the stiffener, thickness of the plating and depth of the stiffener as the design variables, Sequential Unconstrained Minimization Technique (SUMT) has been used to solve the design problem. RBO has been carried out to get the optimal values of these design variables for a target reliability index using Interior Penalty Function Method for which an efficient computer code in C++ has been developed.

Design of Transverse-Plane Bulkheads in Tankers

1976 ◽  
Vol 20 (02) ◽  
pp. 67-78
Author(s):  
Carl Arne Carlsen ◽  
Dag Kavlie
Keyword(s):  
Computer Aided Design ◽  
Three Dimensional ◽  
Unconstrained Minimization ◽  
Optimization Methods ◽  
Transverse Plane ◽  
Design Stage ◽  
Preliminary Design Stage ◽  
Minimization Technique ◽  
Institute Of Technology ◽  
Aided Design

A program system, INDETS, for computer-aided design of tanker structures has been developed. The system, which is the result of a joint effort of the Norwegian Institute of Technology, Trondheim, and the Aker Group, Oslo, is considered an effective tool for practical design. A design module of INDETS for tanker transverse-plane bulkheads is presented. The girder system is analyzed by a three-dimensional frame model including the surrounding structure as substructures. Two optimization methods, the Stress Ratio Technique and the Sequential Unconstrained Minimization Technique, are applied. A number of parametric variations on topology have been performed, and the depth and breadth have been varied to derive curves for estimating the weight of bulkheads at the preliminary design stage. As a conclusion, a simple-formula is presented.

scholarly journals Modeling and Optimization of Potable Water Network

2000 ◽  
Author(s):  
Berge Djebedjian ◽  
Ahmed Herrick ◽  
Magdy Abou Rayan
Keyword(s):  
System Design ◽  
Distribution System ◽  
Water Distribution ◽  
Potable Water ◽  
Water Distribution System ◽  
Optimization Technique ◽  
Unconstrained Minimization ◽  
Pipe Diameter ◽  
Water Network ◽  
Minimization Technique

A potable water network hydraulic analysis is presented in this paper. A mathematical model was developed, the model treats looped network. A computer program is developed in order to facilitate water distribution system design, which satisfies all constraints including pipe diameter and nodal pressure. An optimization technique is developed in order to evaluate the optimum network configuration and cost, the parameters are pipe diameter, flow rate, corresponding pressure and hydraulic losses. A non-linear technique was adopted in the solution. The model uses the sequential unconstrained minimization technique (SUMT) of Fiacco and McCormick (1964) to solve the optimal design of network. The adopted optimization technique decreases the required number of design iterations which for example may reach 1.48 billion iterations for a network with 8 pipes and a set of 14 available commercial pipes. The initially assumed pipe diameters are successively adjusted to suit the existing standard commercial pipe diameters. The technique was applied on a simple case study of gravity-fed network. The objective of the present investigation is to present a practical tool to help in the optimization of water distribution system, design and operation.

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