Weight and Cost Optimization of Midship Section Using Common Structural Rules

2020 ◽  
Vol 36 (03) ◽  
pp. 171-180
Author(s):  
Mesbah Sayebani ◽  
Abdolhossein Mohammadrahimi ◽  
Hossein Khoshdel Looyeh
Keyword(s):  
Limit State ◽  
Optimization Technique ◽  
Cost Optimization ◽  
Optimal Solution ◽  
Optimization Procedure ◽  
Computational Tool ◽  
Structural Rules ◽  
Ship Construction ◽  
The Common ◽  
Common Structural Rules

Cost and weight optimization in ship construction are usually investigated in the form of a multiobjective optimization problem. So far, many studies have been carried out to achieve various types of existing optimization objectives and different tools have been developed. Most of the studies in the field of structural optimization have focused on comparing the available optimization algorithms. In this study, a rule-based tool is developed based on the Common Structural Rules (CSRs), which despite its simplicity in application, provides high capabilities in producing an optimal solution. In the developed tool, structural analysis of serviceability limit state is performed by using the relationships of CSRs. The computational tool is created by MATLAB software (Mathworks, Natick, Massachusetts), and the optimization technique is a genetic algorithm. The performance of the computational tool is evaluated by analyzing the midship section of a chemical tanker. In the optimization procedure, weight and cost are assumed to have the same importance. From the results of the developed tool, all components of the weight and cost of ship construction decreased in the optimal solution relative to the initial design.

Evaluation of IACS Common Structural Rules in Terms of Ultimate Limit State Design and Assessment of Ship Structures

2007 ◽  
Author(s):  
Jeom Kee Paik ◽  
Bong Ju Kim ◽  
Jung Kwan Seo
Keyword(s):  
Limit State ◽  
Bending Moment ◽  
Ultimate Limit State ◽  
Stiffened Plate ◽  
Plate Structures ◽  
Hull Girder ◽  
Structural Rules ◽  
Out Of Plane ◽  
Common Structural Rules ◽  
Ultimate Limit

The aim of the present paper is to evaluate the ultimate limit state performance of an AFRAMAX-class hypothetical double hull oil tanker structure designed by IACS CSR (Common Structural Rules) method, compared with the same-class/type tanker structure designed by IACS pre-CSR method. The ultimate strengths of stiffened plate structures in deck and bottom parts under combined in-plane and out-of-plane actions, and hull girder against vertical bending moment, are computed for the two designs, and the resulting computations are compared. ALPS/ULSAP program is used for the ultimate limit state assessment of stiffened plate structures, while ALPS/HULL program is employed for the progressive hull collapse analysis. ANSYS nonlinear FEA method, which uses more refined technology, is also used for the same purpose. The insights and developments obtained from the present study are addressed.

The Development of Common Structural Rules for Tankers

2005 ◽  
Author(s):  
Gary E. Horn
Keyword(s):  
General Public ◽  
Development Process ◽  
Project Team ◽  
Structural Requirements ◽  
Technical Aspects ◽  
Structural Rules ◽  
Standardization Process ◽  
The Common ◽  
Common Structural Rules ◽  
The Impact

In late 2001 classification societies Lloyd’s Register, the American Bureau of Shipping and Det Norske Veritas (LR, ABS and DNV) announced plans to standardize a wide number of mutually agreed upon initiatives covering survey and engineering. This standardization process was precipitated as a response to calls for more robust requirements as well as a Class response to calls for improvement made by governments, industry and the general public. One of the initiatives was the establishment of a joint tanker project team (JTP) to develop Common Structural Rules for Tankers so that competition on structural requirements (safety) would be eliminated. Once the common rules are finalized and in effect, they will replace the current tanker rules of LR, ABS and DNV. This paper outlines the rule development process, key technical aspects of the common rules, the impact to the design scantlings, and future maintenance of these rules.

scholarly journals Two-Stage Optimization Method for the Bearing Layout of Isolated Structure

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Yu Dang ◽  
GenXiong Zhao ◽  
HongTu Tian ◽  
Guobao Li
Keyword(s):  
Optimization Technique ◽  
Optimal Solution ◽  
Nonlinear Behavior ◽  
Optimization Procedure ◽  
Optimization Method ◽  
Design Parameters ◽  
Two Stage ◽  
Factors Affecting ◽  
Lead Rubber Bearing ◽  
The Cost

Design of seismic isolated building is often a highly iterative and tedious process due to the nonlinear behavior of the system, a large range of design parameters, and uncertainty of ground motions. It is needed to consider a comprehensive optimization procedure in the design of isolated buildings with optimized performances. This can be accomplished by applying a rigorous optimization technique. However, due to many factors affecting the performance of isolated buildings, possible solutions are abundant, and the optimal solution is difficult to obtain. In order to simplify the optimization process, an isolated building is always modeled as a shear-type structure supported on the isolated layer, and the optimal results are the parameters of the isolated layer which could not be used as a practical design of the isolated structure. A two-stage optimization method for designing isolated buildings as a practical and efficient guide is developed. In the first stage, a 3D isolated building model is adopted that takes into account of nonlinear behavior in building and isolation devices. The isolation devices are simplified as a kind of lead-rubber bearing. The genetic algorithm is used to find the optimal parameters of the isolated layer. In the second stage, the location parameters of isolation bearing layout are optimized. Moreover, the cost of the isolation bearing layout should be as low as possible. An integer programming method is adopted to optimize the number of each type of isolator. Considering vertical bearing capacity of isolators and the minimum eccentricity ratio of the isolated layer, the optimal bearing layout of the isolated building can be obtained. The proposed method is demonstrated in a typical isolated building in China. The optimum bearing layout of the isolated building effectively suppresses the structural seismic responses, but the cost of the isolated layer might slightly increase.

Ultimate Limit State Performance of 170k Bulk Carrier Structures: Pre-CSR versus CSR Designs

2009 ◽  
Vol 46 (03) ◽  
pp. 174-182
Author(s):  
Jeom kee Paik ◽  
Jin Young Kim ◽  
Min Soo Kim
Keyword(s):  
Limit State ◽  
Bending Moment ◽  
Ultimate Limit State ◽  
Stiffened Plate ◽  
Bulk Carrier ◽  
Plate Structures ◽  
Structural Rules ◽  
Similar Class ◽  
Common Structural Rules ◽  
Ultimate Limit

The objective of the present paper is to evaluate the ultimate limit state (ULS) performance of 170k bulk carrier structures designed by the IACS common structural rules (CSR) method, compared with the similar-class/type bulk carrier structure designed by the IACS pre-CSR method. The ultimate strengths of stiffened plate structures in deck, side, and bottom parts, and hull girders against vertical bending moment, are computed for the two designs, and the resulting computations are compared. ALPS/ULSAP program is used for the ultimate limit state assessment of stiffened plate structures, and ALPS/HULL program is employed for the progressive hull collapse analysis. The insights and developments obtained from the present study are documented.

Estimation of Ultimate Limit Statefor Stiffened-Plates Structures: Applying for a Very Large Ore Carrier Structures Designed by IACS Common Structural Rules

2012 ◽  
Vol 249-250 ◽  
pp. 1012-1018
Author(s):  
Hung Chien Do ◽  
Wei Jiang ◽  
Jian Xin Jin
Keyword(s):  
International Association ◽  
Limit State ◽  
Offshore Structures ◽  
Biaxial Compression ◽  
Stiffened Plates ◽  
Ultimate Limit State ◽  
Ship Structures ◽  
Structural Rules ◽  
Common Structural Rules ◽  
Ultimate Limit

In advanced marine industry, the reduction in weight of hull structures for a very large object ship plays an important role as the economic efficiency is the most significant aspect. In this paper, we investigate the ultimate strength of structural ship stiffened-plates designed by International Association of Classification Societies (IACS) Common Structural Rules (CSR) methods of collapse state, by applying for ANSYS nonlinear finite element analysis (FEA). Specifically, the ultimate limit assessment methods for the outer bottom of ship structures, which have drawn a significant attention from industrial marine and offshore structures, are proposed to reduce the weight of ship structures. To solve this, we study the structures of a hypothetical Very Large Ore Carrier (VLOC) designed by pre-CSR and CSR methods. In particular, the stiffened-plates under the biaxial compression and lateral pressure loads with simply supported or/and clamped boundary condition(s), the results ultimate limit state assessment performance of Nonlinear FEA methods are shown and compared to various states.

Well Placement Technique and Production Optimization for Mature Field - A Case Study of L-X Field

2020 ◽  
Vol 46 ◽  
pp. 168-179
Author(s):  
Patrick Nwafor ◽  
Kelani Bello
Keyword(s):  
Oil And Gas ◽  
Optimization Technique ◽  
Optimal Solution ◽  
Oil And Gas Industry ◽  
Optimization Method ◽  
Simulation Software ◽  
Production Optimization ◽  
Direct Optimization ◽  
Well Placement ◽  
Local Optimal Solution

A Well placement is a well-known technique in the oil and gas industry for production optimization and are generally classified into local and global methods. The use of simulation software often deployed under the direct optimization technique called global method. The production optimization of L-X field which is at primary recovery stage having five producing wells was the focus of this work. The attempt was to optimize L-X field using a well placement technique.The local methods are generally very efficient and require only a few forward simulations but can get stuck in a local optimal solution. The global methods avoid this problem but require many forward simulations. With the availability of simulator software, such problem can be reduced thus using the direct optimization method. After optimization an increase in recovery factor of over 20% was achieved. The results provided an improvement when compared with other existing methods from the literatures.

Application of UPFC for enhancement of voltage profile and minimization of losses using Fast Voltage Stability Index (FVSI)

2012 ◽  
Vol 61 (2) ◽  
pp. 239-250 ◽  
Author(s):  
M. Kumar ◽  
P. Renuga
Keyword(s):  
Power System ◽  
Voltage Stability ◽  
Reactive Power ◽  
Optimization Technique ◽  
Optimal Solution ◽  
Stability Index ◽  
Test System ◽  
Unified Power Flow Controller ◽  
Voltage Profile ◽  
Voltage Stability Index

Application of UPFC for enhancement of voltage profile and minimization of losses using Fast Voltage Stability Index (FVSI)Transmission line loss minimization in a power system is an important research issue and it can be achieved by means of reactive power compensation. The unscheduled increment of load in a power system has driven the system to experience stressed conditions. This phenomenon has also led to voltage profile depreciation below the acceptable secure limit. The significance and use of Flexible AC Transmission System (FACTS) devices and capacitor placement is in order to alleviate the voltage profile decay problem. The optimal value of compensating devices requires proper optimization technique, able to search the optimal solution with less computational burden. This paper presents a technique to provide simultaneous or individual controls of basic system parameter like transmission voltage, impedance and phase angle, thereby controlling the transmitted power using Unified Power Flow Controller (UPFC) based on Bacterial Foraging (BF) algorithm. Voltage stability level of the system is defined on the Fast Voltage Stability Index (FVSI) of the lines. The IEEE 14-bus system is used as the test system to demonstrate the applicability and efficiency of the proposed system. The test result showed that the location of UPFC improves the voltage profile and also minimize the real power loss.

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