This book is the first monograph focusing on ellipsoidal heads, which are commonly used as an end closure of pressure vessels in chemical, petroleum, nuclear, marine, aerospace and food processing industries. It provides a comprehensive coverage of stress, failure, design and fabrication of ellipsoidal heads. This book investigates in detail buckling/plastic collapse behaviors of ellipsoidal heads using nonlinear finite element methods and experiments. Buckling/plastic collapse experiments are performed on 37 ellipsoidal heads which cover various geometric parameters, material and fabrication methods. In particular, modern measurement technologies, such as 3D laser scanning, are used in the experiments of these ellipsoidal heads including large heads with a diameter up to 5 metres. Moreover, this book presents new formulas for accurate prediction of buckling/plastic collapse pressures of ellipsoidal heads. Using elastic-plastic theory, this book proposes a new failure mechanism-based method for design of ellipsoidal heads. Compared to other methods in current codes and standards based on elastic or perfectly plastic theory, the new design method can fully develop the head’s load-carrying capacity, which reduces head thickness and thus cost. Also, this book studies control on fabrication quality of ellipsoidal heads, including shape deviation, forming strain and forming temperature. It is useful as a technical reference for researchers and engineers in the fields of engineering mechanics, engineering design, manufacturing engineering and industrial engineering.
Author(s): Jinyang Zheng, Keming Li
Publisher: Springer
Year: 2021
Language: English
Pages: 206
City: Singapore
Preface
Contents
Nomenclature
1 Introduction
1.1 General
1.1.1 Head Types
1.1.2 Steel and Its Mechanical Properties
1.1.3 Application
1.2 Stress of Ellipsoidal Heads
1.2.1 Elastic Analysis
1.2.2 Elastic–Plastic Analysis
1.2.3 Stress Comparison Between Ellipsoidal and Torispherical Heads
1.3 Failure Prediction of Ellipsoidal Heads
1.3.1 Failure Mode
1.3.2 Plastic Collapse
1.3.3 Local Buckling
1.4 Design of Ellipsoidal Heads
1.4.1 Design Standards
1.4.2 Protection Against Plastic Collapse
1.4.3 Protection Against Local Buckling
1.5 Fabrication of Ellipsoidal Heads
1.5.1 Fabrication Methods
1.5.2 Quality Requirements
1.6 Special Ellipsoidal Heads
1.6.1 Heads Under External Pressure
1.6.2 Heads with Variable Thicknesses
1.6.3 Heads with Nozzles
References
2 Buckling of Ellipsoidal Heads
2.1 Concept of Buckling
2.2 Key Technologies for Buckling Test of Large (Φ5000) Ellipsoidal Heads
2.2.1 Design of Reusable Test Vessel with Large Ellipsoidal Heads
2.2.2 Measurement of Initial Shape and Deformation with 3D Laser Scanner
2.2.3 Measurement of Large Strain Under Hydraulic Pressure
2.3 Finite Element Models for Buckling Simulation
2.3.1 Heads with Perfect Shape
2.3.2 Heads with Actual Shape
2.4 Buckling Behavior
2.4.1 Determination of Local Buckling Pressure
2.4.2 Characteristics of Buckling
2.4.3 Influencing Factors of Buckling
2.4.4 Development of Buckling Criterion
2.5 Formula for Predicting Buckling Pressure
2.5.1 Parameter Study
2.5.2 Development of New Formula
2.5.3 Comparison Between New Formula and Existing Formulas
References
3 Plastic Collapse of Ellipsoidal Heads
3.1 Introduction to Plastic Collapse
3.2 Plastic Collapse Experiment
3.2.1 Experimental Setup
3.2.2 Rupture Characteristics
3.2.3 Geometric Strengthening Phenomenon
3.2.4 Plastic Collapse Pressure
3.3 Prediction of Plastic Collapse Pressure
3.3.1 Finite Element Model
3.3.2 Finite Element Analysis Results
3.3.3 Influencing Factors of Plastic Collapse Pressure
3.4 Formula for Predicting Plastic Collapse Pressure
3.4.1 Parameter Study
3.4.2 Development of New Formula Considering Nonlinearity Strengthening
3.4.3 Experiment Verification
3.4.4 Analysis and Discussion
References
4 New Method for Design of Ellipsoidal Heads
4.1 Problems of Current Design Methods
4.1.1 Local Buckling Criteria
4.1.2 Geometric Equivalence as Torispherical Heads
4.1.3 Strengthening Effect of Nonlinearity on Strength
4.2 Failure Mechanism-Based Design Method
4.2.1 Applicability Scope
4.2.2 Formula for Preventing Local Buckling
4.2.3 Formula for Preventing Plastic Collapse
4.2.4 New Design Method for Ellipsoidal Heads Under Internal Pressure
4.3 Comparison Between New Method and Those in Standards
4.3.1 Comparison of Applicability Scope
4.3.2 Comparison of Required Thickness
4.3.3 Advantages of New Method
References
5 Control of Fabrication Quality of Ellipsoidal Heads
5.1 Effects of Fabrication on Head Performance
5.1.1 Effects of Shape Deviation on Buckling Pressure
5.1.2 Effects of Forming Strain on Mechanical Properties
5.1.3 Effects of Forming Temperature on Mechanical Properties
5.2 Shape Deviation
5.2.1 Non-contact Measurement of Shape Deviation
5.2.2 Characterization of Shape Deviation
5.2.3 Evaluation Method of Shape Deviation Using Non-Contact Measurement
5.3 Forming Strain
5.3.1 Head Forming Simulation
5.3.2 Measurement of Forming Strain and Simulation Validation
5.3.3 Formula for Predicting Forming Strain
5.3.4 Comparison of Different Formulas for Predicting Forming Strain
5.4 Forming Temperature
5.4.1 Mechanical Properties at Different Temperatures
5.4.2 Strain-Induced Martensitic Transformation of Austenitic Stainless Steel
5.4.3 Method for Determining Warm Forming Temperature
5.4.4 Advantages of Warm Forming
References
6 Summary
