Research on Direct Calculation of Yielding and Buckling Strength Based on Jtp Rules for Oil Tankers

摘要

In order to satisfy the requirement of Maritime Organization and ship owner,IACS established the common Structural Rules for Oil Tanker (CSR), which came into effect at 1st April 2006.The CSR is based on the concept of target ship; it has contained the experience and latest research results of members of IACS. The yielding and buckling, which are usually defined two main failure modes for ship structure, are especially defined in CSR. This paper mainly researches the assessment of yielding strength by FEM and advanced buckling analysis according to the CSR. The main contents are appended below:1) Introduce the technology of FEM in CSR, including modeling, loading,definition of Load cases and the adjustment of shear force and bending moment. Research the theoretical background of FEM according to the CSR by use of basic mechanics principles and equal design wave approach (EDW).2) The midship cargo tank FE model is established by means of ANSYS software.3) Research on the advanced buckling analysis in CSR; discuss the main impactions and theoretical background of the advanced buckling analysis.Give a brief review of the theoretical background, design principles and purpose of PULS, which is procedure recommended by IACS to assess the buckling strength.4) Research on the buckling assessment method in software of PULS,including a simplified method for elastic large angle deflection analysis of plates and stiffened panels due to local buckling.5) The yielding strength, buckling strength assessment was done according to the JTP Rules. According to the conclusion of results, the different impactions of Load cases are suggested.

目录

英文文摘

声明

Acknowledgement

CHAPTER1INTRODUCTION

1.1 Introduction to JTP Rules

1.2 Aim Of Rules

1.3 Brief Description of the Work/Analysis

CHAPTER2.0CARGOTANKSTRUCTURALSTRENGTHANALYSIS

2.1 Structural Modeling

2.2 Reduced Thickness Approach

2.3 Meshing

2.4 Boundary Conditions

2.5 Boundary Constraints at Model Ends

2.6 Modeling and Boundary Conditions Application

CHAPTER3.0LOADS

3.1 Load Cases

3.2 Combination of Loads

3.3 Static Load Components

3.3.1 Static Hull Girder Loads

3.3.2 Local Static Loads

3.4 Dynamic Load Components

3.4.1 Vertical Wave Bending Moment

3.4.2 Horizontal wave bending moment

3.4.3 Vertical wave shear force

3.5 Dynamic Local Loads

3.5.1 Dynamic wave pressure

3.5.2 Green sea loads

3.5.3 Dynamic tank pressure

3.5.4 Dynamic deck pressure from distributed loading

3.5.5 Dynamic loads from heavy units

3.6 Loads Application on Model

CHAPTER4.0APPLICATIONOFLOADS

4.1 Heading correction factor and dynamic load combination factors

4.2 Vertical wave bending moment for a considerable dynamic load case

4.3 Horizontal wave bending moment for a considerable dynamic load case

4.4 Vertical wave shear force for a considerable dynamic load case

4.5 Dynamic Wave Pressure Distribution for a Considerable Dynamic Load Case

4.6 Green sea load for a considerable dynamic load case

4.7 Simultaneously acting Green sea load for a considerable dynamic load case

4.8 Procedure to adjust hull girder shear forces and bending moments

CHAPTER5.0PULBUCKLINGASSESSMENT

5.1 PULS (PANELS ULTIMATE LIMIT STATE)

5.2 Element U3: Unstiffened Plate

5.3 Element S3: Uni-axially Stiffened Plate

5.4 Element T1: Stiffened Plate with Non-Regular Geometry

5.5 Approach

5.6 Extemal Prescribed Loads

5.7 S3: Stiffened Panel Element

5.8 Local Eigenvalue; LEB

5.9 Lateral Pressure

5.10 Material Law and Kinematics Relationship

5.11 Buckling Strength of Stiffened Panels

5.12 Definition of Global Stiffness Coefficient

5.13 Global Buckling Model

CHAPTER6.0CASESTUDYANDRESULTSVALIDATION

6.1 General

6.2 Aframax

6.3 Reduced Thickness Approach

6.4 Element Consideration for Analysis

6.5 Yielding Strength of Elements in comparison to JTP

6.6 Results, Discussion and Analysis

6.7 Buckling Assessment of Elements in comparison to JTP

6.8 Local Fine Mesh Structural Strength Analysis

6.9 Most Critically Stressed Areas

6.10 Comparison between JTP Rule Formula and Direct Calculation

6.11 Comparison between JTP and CCS

CHAPTER7.0CONCLUSIONANDRECOMMENDATIONS

7.1 Conclusion

7.2 Recommendations

APPENDIX

References