Topology optimization of Oil Tanker Structures in Cargo Tank Region MARIC Topology optimization of Oil Tanker Structures in Cargo Tank Region Speaker: GAO Chu October 2016 QIU Weiqiang, GAO Chu, SUN Li, LUO Renjie

Content Proposal for a VLCC with one center line longitudinal bulkhead Introduction to structure optimization techniques Definition of Structural Model, boundary conditions and load patterns FEA Topology results discussion Conclusions MARIC

Hull structure of VLCC and Suezmax size oil tanker Typical transverse section of a Suezmax size oil tanker Typical transverse section of a VLCC VLCC with one C.L. BHD MARIC

Tank arrangements of proposed VLCC and traditional one Traditional VLCC VLCC with one C.L. BHD MARIC

Important issues to be aware of Shear Strength Stringer Design Local Strength MARIC

7.3m 37.02m The “GREAT STONE BRIDGE” An Chi Ch'iao An Chi Ch'iao the Great Stone Bridge Chao Hsien, Hobei, China Sui Dynasty ,AD 569-617, Li Chun Master Builder

Structure Optimization Design Hull Structure Optimization Design Hull Structure Optimization Design Topology Optimization Shape Optimization Size Optimization Structure Optimization Design Production Cost Structure Capability MARIC

Continuum Topology Optimization Methods Homogenization method SIMP （Solid Isotropic Microstructure with Penalty) method ESO/BESO (Evolutionary /Bi-directional Evolutionary Structural Optimization) method ICM (Independent Continuous Mapping) method Level Set method “Killed” element Perimeter Method … SIMP BESO MARIC

Basic Topology Optimization Procedure START FEA Sensitivity Filter Scheme Construct a new design No Yes Converged? END MARIC

Structures to be optimized MARIC

45 Load Cases Loading Patterns and model constraints MARIC Location Translation Rotation δx δy δz θx θy θz Aft End Cross section - Rigid Link Independent point Fix End beam Fore End Crosssection Intersection of CL&IB Where: - no constraint applied (free) MARIC

Problem Statement “Killed” element Empty Solid SIMP BESO MARIC

Structures to be optimized Transverse frames Horizontal Stringers Non-designable Designable MARIC

Structures to be optimized Separated MARIC

Resulting topology of all loading patterns MARIC

Resulting topology of typical transverse frame (all loading patterns) SIMP BESO MARIC

Resulting topology of B3 by SIMP method MARIC

Iteration steps in SIMP process without loading patterns B3 & B11 MARIC

Iteration steps in SIMP process without loading patterns B3 & B11 MARIC

Iteration steps in SIMP process without loading patterns B3 & B11 MARIC

Iteration steps in SIMP process without loading patterns B3 & B11 MARIC

Final solution (Iteration 67) Topology Optimized Trans. Frames & H. Stringers Final solution (Iteration 67) MARIC

Optimum topology by SIMP MARIC

Optimum topology by BESO MARIC

Optimum topology of typical transverse frame by SIMP method MARIC

Optimum topology of typical transverse frame by BESO method MARIC

Optimum topology of typical transverse frame MARIC

Optimum topology of typical horizontal stringers by SIMP & BESO method MARIC

Optimized topology & new designs SIMP 01 BESO 02 MARIC

Optimized topology & new designs SIMP BESO MARIC

Web Height Optimization Shape/size optimization Vertical Girder Web Height Optimization Horizontal Stringer Web Height Optimization Deck Transverse Web Height Optimization Size Optimization 01 02 Rule Check Nonlinear FEA Elastic column buckling Elastic torsional buckling Elastic column / torsional buckling Elasto-plastic behavior of the primary support member

BESO/SIMP optimum topology comparisons Compared subjects SIMP BESO Traditional VLCC Comparison(%) Surface areas of typical transverse frames (m2) 575.8 643.3 731.8 78.7% 87.9% Averaged weight of typical transverse webs (ton, except for wash BHD) 100.8 111.3 143.1 70.4% 77.8% Structural weight per meter in cargo hold (ton) 111.75 112.55 127.3 87.8% 88.4% MARIC

Comparison between VLCC with one C.L.BHD and traditional one Transverse section arrangements of VLCC with one C.L.BHD Transverse section arrangements of Traditional VLCC MARIC

Comparison between VLCC with one C.L.BHD and traditional one Horizontal stringer arrangements of VLCC with one C.L.BHD Horizontal stringer arrangements of Traditional VLCC MARIC

Topology optimization with 3D elements MARIC

Topology optimization with 3D elements MARIC

Topology optimization with 3D elements MARIC

Application on other tankers New/Old transverse section design of Suezmax oil tanker MARIC

Application on other tankers New/Old transverse section design of Aframax oil tanker MARIC

Vertical web end of a Aframax size oil tanker Applications Vertical web end of a Aframax size oil tanker MARIC

Conclusions New structural design of a VLCC is proposed Optimum topology of the VLCC with one C.L. BHD calculated and discussed Problems encountered during the optimization procedure Limitations of present optimization tools Issues to be resolved in the future MARIC

THANKS 中 国 船 舶 及 海 洋 工 程 设 计 研 究 院 MARINE DESIGN & RESEARCH INSTITUTE OF CHINA