Optimum Design of Spread Mooring Systems

1982 ◽  
Vol 104 (1) ◽  
pp. 78-83 ◽  
Author(s):  
H. L. Jones ◽  
J. K. Nelson
Keyword(s):  
Optimal Design ◽  
Mathematical Programming ◽  
Optimum Design ◽  
Loading Condition ◽  
Optimization Problem ◽  
Mooring System ◽  
Computer Solution ◽  
Initial Tension ◽  
Design Variables ◽  
Problem Design

The design of a spread mooring system of given pattern with single segment lines on a flat seafloor is formulated as a mathematical programming (optimization) problem. Design variables are the outboard length and initial tension in each line. Constraints limit maximum tension, anchor pull and anchor uplift for each line under each loading condition. Maximum vessel excursion is limited to a circle of specified radius. The optimal design is that which minimizes total weight of outboard line and is obtained by computer solution of the optimization problem. Three examples are presented to demonstrate the method.

Shape Optimization of Hydraulic Structures: an Example of an Optimum Design of a Fish Passage

10.29007/2k64 ◽  
2018 ◽  
Author(s):  
Pat Prodanovic ◽  
Cedric Goeury ◽  
Fabrice Zaoui ◽  
Riadh Ata ◽  
Jacques Fontaine ◽  
...  
Keyword(s):  
Numerical Model ◽  
Shape Optimization ◽  
Objective Function ◽  
Optimum Design ◽  
Optimization Problem ◽  
A Priori ◽  
Coupled System ◽  
Fish Passage ◽  
Hydraulic Structures ◽  
Design Variables

This paper presents a practical methodology developed for shape optimization studies of hydraulic structures using environmental numerical modelling codes. The methodology starts by defining the optimization problem and identifying relevant problem constraints. Design variables in shape optimization studies are configuration of structures (such as length or spacing of groins, orientation and layout of breakwaters, etc.) whose optimal orientation is not known a priori. The optimization problem is solved numerically by coupling an optimization algorithm to a numerical model. The coupled system is able to define, test and evaluate a multitude of new shapes, which are internally generated and then simulated using a numerical model. The developed methodology is tested using an example of an optimum design of a fish passage, where the design variables are the length and the position of slots. In this paper an objective function is defined where a target is specified and the numerical optimizer is asked to retrieve the target solution. Such a definition of the objective function is used to validate the developed tool chain. This work uses the numerical model TELEMAC- 2Dfrom the TELEMAC-MASCARET suite of numerical solvers for the solution of shallow water equations, coupled with various numerical optimization algorithms available in the literature.

scholarly journals A Multi-Level Optimization Method for Elastic Constants Identification of Composite Laminates

2019 ◽  
Vol 9 (20) ◽  
pp. 4267
Author(s):  
Chien Yang Huang ◽  
Tai Yan Kam
Keyword(s):  
Optimal Design ◽  
Elastic Constants ◽  
Composite Laminates ◽  
Composite Laminate ◽  
Optimization Problem ◽  
Optimization Method ◽  
Global Minimization ◽  
Minimization Problems ◽  
Design Variables ◽  
Multi Level

A new and effective elastic constants identification technique is presented to extract the elastic constants of a composite laminate subjected to uniaxial tensile testing. The proposed technique consists of a new multi-level optimization method that can solve different types of minimization problems, including the extraction of material constants of composite laminates from given strains. In the identification process, the optimization problem is solved by using a stochastic multi-start dynamic search minimization algorithm at the first level in order to obtain the statistics of the quasi-optimal design variables for a set of randomly generated starting points. The statistics of the quasi-optimal elastic constants obtained at this level are used to determine the reduced feasible region in order to formulate the second-level optimization problem. The second-level optimization problem is then solved using the particle swarm algorithm in order to obtain the statistics of the new quasi-optimal elastic constants. The iteration process between the first and second levels of optimization continues until the standard deviations of the quasi-optimal design variables at any level of optimization are less than the prescribed values. The proposed multi-level optimization method, as well as several existing global optimization algorithms, is used to solve a number of well-known mathematical minimization problems to verify the accuracy of the method. For the adopted numerical examples, it has been shown that the proposed method is more efficient and effective than the adopted global minimization algorithms to produce the exact solutions. The proposed method is then applied to identify four elastic constants of a [0°/±45°]s composite laminate using three strains in 0°, 45°, and 90° directions, respectively, of the composite laminate subjected to uniaxial testing. For comparison purposes, several existing global minimization techniques are also used to solve the elastic constants identification problem. Again, it has been shown that the proposed method is capable of producing more accurate results than the adopted available methods. Finally, experimental data are used to demonstrate the applications of the proposed method.

scholarly journals Optimal Design of Shape Memory Alloy Composite under Deflection Constraint

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1733 ◽  
Author(s):  
Yogesh Gandhi ◽  
Alessandro Pirondi ◽  
Luca Collini
Keyword(s):  
Optimal Design ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Optimization Problem ◽  
Edge Length ◽  
Design Parameters ◽  
Stable Configuration ◽  
Alloy Composite ◽  
Bistable Behavior ◽  
Design Variables

Shape-adaptive or morphing capability in both aerospace structures and wind turbine blade design is regarded as significant to increase aerodynamic performance and simplify mechanisms by reducing the number of moving parts. The underlying bistable behavior of asymmetric cross-ply composites makes them a suitable candidate for morphing applications. To date, various theoretical and experiential studies have been carried out to understand and predict the bistable behavior of asymmetric laminates and especially the curvature obtained in their stable configurations. However, when the bi-stable composite plate is integrated with shape memory alloy wires to control the curvature and to snap from a stable configuration to the other (shape memory alloy composite, SMAC), the identification of the design parameters, namely laminate edge length, ply thickness and ply orientation, is not straightforward. The aim of this article is to present the formulation of an optimization problem for the parameters of an asymmetric composite laminate integrated with pre-stressed shape memory alloys (SMA) wires under bi-stability and a minimum deflection requirement. Wires are modeled as an additional ply placed at the mid-plane of the composite host plate. The optimization problem is solved numerically in MATLAB and optimal design variables are then used to model the SMAC in ABAQUS™. Finite element results are compared against numerical results for validation.

Vehicle Handling Dynamics Optimization Based in Passive Suspension Settings in Target Cascading Framework

2014 ◽  
Author(s):  
Juan C. Blanco ◽  
Luis E. Muñoz
Keyword(s):  
Optimal Design ◽  
Optimization Problem ◽  
Suspension System ◽  
Dynamics Simulation ◽  
Design Stage ◽  
Partial Geometry ◽  
Embodiment Design ◽  
Design Variables ◽  
Target Cascading

The vehicle optimal design is a multi-objective multi-domain optimization problem. Each design aspect must be analyzed by taking into account the interactions present with other design aspects. Given the size and complexity of the problem, the application of global optimization methodologies is not suitable; hierarchical problem decomposition is beneficial for the problem analysis. This paper studies the handling dynamics optimization problem as a sub-problem of the vehicle optimal design. This sub-problem is an important part of the overall vehicle design decomposition. It is proposed that the embodiment design stage can be performed in an optimal viewpoint with the application of the analytical target cascading (ATC) optimization strategy. It is also proposed that the design variables should have sufficient physical significance, but also give the overall design enough design degrees of freedom. In this way, other optimization sub-problems can be managed with a reduced variable redundancy and sub-problem couplings. Given that the ATC strategy is an objective-driven methodology, it is proposed that the objectives of the handling dynamics, which is a sub-problem in the general ATC problem, can be defined from a Pareto optimal set at a higher optimization level. This optimal generation of objectives would lead to an optimal solution as seen at the upper-level hierarchy. The use of a lumped mass handling dynamics model is proposed in order to manage an efficient optimization process based in handling dynamics simulations. This model contains detailed information of the tire properties modeled by the Pacejka tire model, as well as linear characteristics of the suspension system. The performance of this model is verified with a complete multi-body simulation program such as ADAMS/car. The handling optimization problem is presented including the proposed design variables, the handling dynamics simulation model and a case study in which a double wishbone suspension system of an off-road vehicle is analyzed. In the case study, the handling optimization problem is solved by taking into account couplings with the suspension kinematics optimization problem. The solution of this coupled problem leads to the partial geometry definition of the suspension system mechanism.

Optimal Design of Electric Overhead Crane Girders

1984 ◽  
Vol 106 (2) ◽  
pp. 203-208
Author(s):  
S. W. Cho ◽  
B. M. Kwak
Keyword(s):  
Sensitivity Analysis ◽  
Optimal Design ◽  
Mathematical Programming ◽  
Computer Program ◽  
Optimum Design ◽  
Minimum Weight ◽  
Steepest Descent ◽  
Overhead Crane ◽  
Simply Supported ◽  
Steepest Descent Algorithm

An optimal design for minimum weight bridge girders of electric overhead traveling cranes is presented. The welded box-type girder is modeled as a simply supported beam. A generalized steepest descent algorithm is adopted for mathematical programming, which includes constraints on stress, displacement, buckling, and sizes. A computer program capable of designing girders according to CMAA, DIN, BS, and JIS specifications is developed. Numerical comparisons with existing girders for those four specifications are given. A sensitivity analysis of the optimum design with respect to parameters affecting the design is studied for each specification.

scholarly journals Optimal design for improving torque performance of permanent magnet motor

2018 ◽  
Vol 7 (2.12) ◽  
pp. 292
Author(s):  
Tae Kyoung Bang ◽  
Kyung Hun Shin ◽  
Jeong In Lee ◽  
Cheol Han ◽  
Sung Kook Cho ◽  
...  
Keyword(s):  
Optimal Design ◽  
Taguchi Method ◽  
Objective Function ◽  
Permanent Magnet ◽  
Optimum Design ◽  
Optimization Process ◽  
Bldc Motor ◽  
Original Design ◽  
Design Point ◽  
Design Variables

Background/Objectives: This paper deals with the optimal design of the BLDC motor considering a rotor structure that is used to electrically drive tools. Generally, electrically driven tools employ the BLDC motor, which should be able to operate in high-speed and high-vibration environments. However, it has the disadvantages of a high torque ripple and significant waveform fluctuation. Therefore, it is necessary to optimize it according to the usage condition.Methods/Statistical analysis: In improving the torque performance, this study performed the optimization process by employing the Taguchi method, which can achieve a robust design based on the design variables. In the optimization process, the objective functions are set using a weighting ratio depending on the importance of the objective function as back EMF, torque performance, and loss. Through the optimization process, the optimal design point that improved the performance of the objective function is derived. The improved design that applied the optimal design point is compared with the original design by using the finite element method (FEM) analysis results.Findings: In this study, the optimum design of the motor according to the design variables and the objective function is derived through the optimum design method using the Taguchi method by adopting the motor for the electrically driven tool as the interior permanent magnet type BLDC motor and the FEM results. Moreover, by comparing the analysis results with the optimized model and the initial model, the optimum design point that satisfies the restriction specification and the rated specification was found.Improvements/Applications: The optimum design point was found by using the Taguchi method and the loss and torque characteristics were improved. 

Variational Approach in Optimal Design of Piezoelectric Sensors & Actuators

2008 ◽  
Vol 47-50 ◽  
pp. 1258-1261
Author(s):  
Aleksander Muc ◽  
Piotr Kędziora
Keyword(s):  
Optimal Design ◽  
Optimization Problem ◽  
Ritz Method ◽  
Present Formulation ◽  
Multilayered Structures ◽  
New Class ◽  
Classical Design ◽  
Design Variables ◽  
Proposed Model ◽  
Ply Orientation

A new optimization problem for laminated multilayered structures having surface bounded piezoelectric patches have been formulated and solved. The present formulation introduces boundaries of piezoelectric patches as new class of design variables. In addition classical design variables in the form of ply orientation angles of orthotropic layers are also taken into account. The design objective is the minimization of normal maximal deflections. The standard Rayleigh-Ritz method is used, however, the accuracy of optimal design are verified with the aid of the FE package ABAQUS. Examples are presented to illustrate the performance of the proposed model.

scholarly journals Prediction of Optimal Design and Deflection of Space Structures Using Neural Networks

2012 ◽  
Vol 2012 ◽  
pp. 1-18 ◽  
Author(s):  
Reza Kamyab Moghadas ◽  
Kok Keong Choong ◽  
Sabarudin Bin Mohd
Keyword(s):  
Neural Networks ◽  
Optimal Design ◽  
Double Layer ◽  
Optimization Problem ◽  
Computational Cost ◽  
Space Structures ◽  
Maximum Deflection ◽  
Cross Sectional ◽  
Design Variables ◽  
Low Computational Cost

The main aim of the present work is to determine the optimal design and maximum deflection of double layer grids spending low computational cost using neural networks. The design variables of the optimization problem are cross-sectional area of the elements as well as the length of the span and height of the structures. In this paper, a number of double layer grids with various random values of length and height are selected and optimized by simultaneous perturbation stochastic approximation algorithm. Then, radial basis function (RBF) and generalized regression (GR) neural networks are trained to predict the optimal design and maximum deflection of the structures. The numerical results demonstrate the efficiency of the proposed methodology.

Efficient Sensitivity Analysis for Multibody Dynamics Systems Using an Iterative Steps Method With Application in Topology Optimization

2011 ◽  
Author(s):  
Guang Dong ◽  
Zheng-Dong Ma ◽  
Gregory Hulbert ◽  
Noboru Kikuchi ◽  
Sudhakar Arepally ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Topology Optimization ◽  
Multibody Dynamics ◽  
Optimization Problem ◽  
Finite Difference Methods ◽  
Analysis Method ◽  
Topology Optimization Problem ◽  
Design Variables ◽  
Sensitivity Analysis Method ◽  
Rotational Motions

Efficient and reliable sensitivity analyses are critical for topology optimization, especially for multibody dynamics systems, because of the large number of design variables and the complexities and expense in solving the state equations. This research addresses a general and efficient sensitivity analysis method for topology optimization with design objectives associated with time dependent dynamics responses of multibody dynamics systems that include nonlinear geometric effects associated with large translational and rotational motions. An iterative sensitivity analysis relation is proposed, based on typical finite difference methods for the differential algebraic equations (DAEs). These iterative equations can be simplified for specific cases to obtain more efficient sensitivity analysis methods. Since finite difference methods are general and widely used, the iterative sensitivity analysis is also applicable to various numerical solution approaches. The proposed sensitivity analysis method is demonstrated using a truss structure topology optimization problem with consideration of the dynamic response including large translational and rotational motions. The topology optimization problem of the general truss structure is formulated using the SIMP (Simply Isotropic Material with Penalization) assumption for the design variables associated with each truss member. It is shown that the proposed iterative steps sensitivity analysis method is both reliable and efficient.

Structural Analysis and Optimal Design of Lightweight Skate for Loading and Unloading

2013 ◽  
Vol 785-786 ◽  
pp. 1258-1261
Author(s):  
In Pyo Cha ◽  
Hee Jae Shin ◽  
Neung Gu Lee ◽  
Lee Ku Kwac ◽  
Hong Gun Kim
Keyword(s):  
Topology Optimization ◽  
Structural Analysis ◽  
Optimal Design ◽  
Optimization Techniques ◽  
Normal Operation ◽  
Stress And Strain ◽  
Initial Model ◽  
Design Variables ◽  
Model Set ◽  
Main Frame

Topology optimization and shape optimization of structural optimization techniques are applied to transport skate the lightweight. Skate properties by varying the design variables and minimize the maximum stress and strain in the normal operation, while reducing the volume of the objective function of optimal design and Skate the static strength of the constraints that should not degrade compared to the performance of the initial model. The skates were used in this study consists of the main frame, sub frame, roll, pin main frame only structural analysis and optimal design was performed using the finite element method. Simplified initial model set design area and it compared to SM45C, AA7075, CFRP, GFRP was using the topology optimization. Strength does not degrade compared to the initial model, decreased volume while minimizing the stress and strain results, the optimum design was achieved efficient lightweight.

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