Finite Element Method Analysis for Ice Class Vessels/Анализ методом конечных элементов для судов ледового класса

Издание на английском языке
The book provides shipbuilders with clear recommendations on alternative design procedures for on-board structures, methods for determining power requirements and evaluating the strength of propellers using the Finite Element Method (FEM) for Baltic ice-class vessels. It covers key aspects of the design of vessels designed to operate in icy conditions, including structural reinforcement calculations, power assessment, and strength analysis of propellers. Despite careful verification of the information, readers are advised to contact the relevant classification society for up-to-date data and recommendations on ship design and operation.

Contents
1 Ice Strengthening Using Direct Calculation Approaches
1.1 Background
1.2 Purpose
1.3 Applications
1.4 Key Components of This Text
Further Reading
2 Procedure for Ice Strengthening Side Structures Using Nonlinear Fem
2.1 Design of Side Structures
2.2 Step 1: FSICR Design
2.3 Step 2: FMA Interim Design
2.4 Step 3: Alternative Design for Side Longitudinals
2.4.1 FEM Modelling
2.4.2 Ice Load on Side Longitudinals
2.4.3 Acceptance Criteria
2.5 Step 4: Alternative Design of Side Shell
2.5.1 FEM Modelling
2.5.2 Ice Load on Side Shell
2.5.3 Acceptance Criteria
2.5.4 Abrasion and/or Corrosion
Further Readings
3 Nonlinear FEM
3.1 Structural Idealisation
3.1.1 Introduction
3.1.2 Extent of Structural Modelling
3.1.3 FEM Elements
3.1.4 Mesh Size
3.2 Material Model
3.3 Boundary Conditions
3.4 Line Load on Side Longitudinals
3.5 Patch Load on Side Shell Plate
3.6 FEM Solution
3.6.1 Incremental solution
3.6.2 Convergence
3.7 Nonlinear FEM Theory and Software
3.7.1 Material Nonlinearity
3.7.2 Geometrical Nonlinearity
3.7.3 Incremental Solutions
3.7.4 Convergence Criteria
3.7.5 Commercial FEM Package
3.8 Example of Nonlinear FEM Applications
3.8.1 Problem Definition
3.8.2 FEM Modelling
3.8.3 Ice Load
3.8.4 Analysis Results
3.9 Alternative Design
3.10 Example of Alternative Side Shell Design
3.11 The Finnish Maritime Administration (FMA) “Tentative Note for Application of Direct Calculation Methods for Longitudinally Framed Hull Structure”
3.11.1 Introduction
3.11.2 Maximum Frame-Spacing
3.11.3 Brackets on Intersections Between Longitudinal Frames and the Web Frames
4 Power Requirement for Ice Class Vessels
4.1 General
4.2 Alternative Methods to Calculate
4.2.1 Analytical Formula for Required Power in Ice
4.3 Direct Calculations of KC Value
4.3.1 Model Test Results
4.3.2 Numerical Simulation
4.3.3 Regression Formula
4.4 Alternative Methods to Determine Rch (Resistance in Brash Ice)
4.4.1 Description of Ice Cover
4.4.2 Estimation of Resistance in Broken Channel
4.5 Examples
References
5 Propeller Strength Assessment
5.1 General Design Basis
5.2 Updated Finnish Swedish Ice Class Rules
5.3 Ice Load Scenarios Considered in Load Formula Development
5.4 Materials Used for Ice Propellers
5.5 Propeller Blade Design
5.6 Design Loads
5.6.1 Maximum Forward and Backward Loads
5.6.2 Ice Load Distributions for Blade Fatigue
5.6.3 Blade Plastic Failure Load
5.7 Blade Stress Analysis Procedure
5.7.1 Simple Formula for Conventional Propeller
5.8 Fem Direct Calculation for Highly Skewed Propeller
5.8.1 Fatigue
5.8.2 Plastic Failure
5.9 Illustrative Example
5.9.1 Information Required for Blade Strength Check
5.10 Load Determination
5.10.1 Stress Analysis
5.11 Blade Strength Check
References