Optimization-Based Multi-Attribute Decision Making for the 7th Generation Semi-Submersible Drilling Unit

2020 ◽  
Author(s):  
Xun Meng ◽  
Pin Tang ◽  
Dejiang Li ◽  
Yu Xu ◽  
Qiang Fu
Keyword(s):  
Decision Making ◽  
Optimal Design ◽  
Work Performance ◽  
Structural Model ◽  
Hydrodynamic Performance ◽  
Strength Analysis ◽  
Drilling Depth ◽  
Element Analysis ◽  
Multi Attribute Decision Making ◽  
Parametric Finite Element Analysis

Abstract The 7th generation semi-submersible drilling units (CSDU) are characteristic of deeper drilling depth, site locations and higher operational efficiency, compared with the last generation ones. Given the enormous live loads change and increasing trend of main size dimensions, considerable optimization should be deployed to achieve a balance of economy, safety and good work performance. Trial calculation and definite assessment to check whether alternative schemes meet the requirements turns out to be ineffective, for the case by case study of hydrodynamic and structure strength analysis is time consuming. In the paper, an integrated optimal design model is formulated by merging multi-objective optimization and multi-attribute decision making into one. A predesigned parametric Finite Element Analysis (FEA) structural model of CSDU is developed and validated and then coupled with detailed hydrodynamic analysis. Three mutually conflicting design objectives are arrived by hydrodynamic solutions. They are stability, hydrodynamic performance and steel consumption, which are screened to obtain Pareto optimality. The Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) is applied to incorporate these optimal attributes into decision-making process, considering all criteria in terms of quantitative stability, hydrodynamic performance and qualitative economy. The objective entropy coefficient measuring the importance of different attributes is introduced into weight selection for the purpose of avoiding non-determinacy and optional judgements. The optimal solutions are further verified with main dimensions of CSDUs in service and also could give predictive suggestion for the new CSDUs. The study provides a more objective way of benchmarking different structural schemes of CSDU by considering multiple criteria simultaneously. It is demonstrated that the proposed structural optimization model is capable of effectively and accurately determining the optimal design of CSDU.

Thermomechanical Evaluation of the Performance and Integrity of a HDPE Stub-End Bolted Flange Connection

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
I. Barsoum ◽  
Z. Barsoum ◽  
M. D. Islam
Keyword(s):  
Nonlinear Response ◽  
Structural Model ◽  
Temperature Dependent ◽  
Element Analysis ◽  
Fea Model ◽  
Operational Window ◽  
And Performance ◽  
Stub End ◽  
Parametric Finite Element Analysis ◽  
Bolted Flange

In this study, the integrity of a manhole structure made of a 78 in. high density polyethylene (HDPE) stub-end, steel ring, and blind flange, sealed with a compressed nonasbestos fiber (CNAF) gasket is investigated by means of a parametric finite element analysis (FEA). A coupled thermomechanical nonlinear FEA model is built, comprising of a heat transfer and a structural model, which allows modeling the complex thermal and mechanical loads and their interactions present during the operation of the manhole. The temperature-dependent elastic–plastic HDPE material constitutive behavior and the temperature-dependent nonlinear response of the CNAF gasket are accounted for in the model. Factors influencing the performance and integrity of the manhole such as stud-bolt pretorque level (Tb), internal pressure (Pi), and outer temperature (To) are considered. Based on the results, the integrity and performance of the structure are assessed in view of a leakage through the gasket criterion and a yielding of the HDPE stub-end criterion. The FEA results reveal that both Tb, Pi, and To significantly influence the performance (i.e., leakage) of the gasket and the integrity (i.e., yielding) of the HDPE stub-end. At 40 °C, it is possible to find a safe operational window for a range of Tb and Pi values, where no leakage through the gasket or yielding of the stub-end occurs. However, as the temperature is increased this safe operational window decreases considerably, and at 80 °C safe operation cannot be guaranteed where leakage, yielding, or both simultaneously, will lead to loss in performance and integrity of the manhole structure.

Study on Ultimate Strength Analysis Method for SWATH Ships

2009 ◽  
Author(s):  
Bin Liu ◽  
Weiguo Wu
Keyword(s):  
Ultimate Strength ◽  
Structural Model ◽  
Strength Analysis ◽  
Test Model ◽  
Load Carrying Capacity ◽  
Test Results ◽  
Analysis Method ◽  
Element Analysis ◽  
Load Carrying ◽  
Ultimate Load Carrying Capacity

Nowadays, numerical calculation and structural model test are mainly applied in the ultimate strength analysis of ship structure. This paper presents the results of an ultimate strength test to determine the ultimate load-carrying capacity of an ocean-survey SWATH ship. A comparison between nonlinear FEA (finite element analysis) for test model and test results is presented. The FE-models of real ship and model ship as well as their relations are studied.

ANALISA KINERJA PEGAWAI UNIVERSITAS METHODIST INDONESIA MENGGUNAKAN FUZZY MULTI ATRIBUT DECISION

2019 ◽  
Vol 3 (1) ◽  
pp. 80-89
Author(s):  
Asaziduhu Gea
Keyword(s):  
Decision Making ◽  
Decision Support ◽  
Work Performance ◽  
Employee Performance ◽  
Fuzzy Model ◽  
Performance Appraisals ◽  
Employee Behavior ◽  
Improve Performance ◽  
Multi Attribute Decision Making

Implementation of performance appraisals needs to be carried out by each organization or agency involving management. In this case the Indonesian Methodist University has Human Resources who carry out their duties in serving service activities with the aim of being able to manage and serve effectively and efficiently. In the role of decision support systems in the context of the overall information system is intended to improve performance through the application of information technology and determine the approach used in the decision making process, to evaluate interactive selection. This software was built using the Fuzzy model with the Multi Attribute Decision Making method. This software provides an assessment based on Job Execution Assessment (DP3), namely loyalty, work performance, responsibility, obedience, honesty, cooperation, initiative and leadership so that the results can be used as decision support for promotion. The importance of the assessment for work requires that the assessment must be truly objective, namely measuring the performance of employees at the true Methodist University of Indonesia ,. This means that the implementation of the assessment must reflect the actual implementation of work and evaluate employee behavior that reflects the success of the implementation of work that results in the satisfaction of people who receive services. Keywords: Decision Support, Fuzzy, Multi Attribute Decision Making, Employee Performance

Multi-Attribute Decision-Making Model by Applying Grey Numbers

Informatica ◽  
2009 ◽  
Vol 20 (2) ◽  
pp. 305-320 ◽  
Author(s):  
Edmundas Kazimieras Zavadskas ◽  
Arturas Kaklauskas ◽  
Zenonas Turskis ◽  
Jolanta Tamošaitienė
Keyword(s):  
Decision Making ◽  
Multi Attribute Decision Making ◽  
Decision Making Model
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