Section 1 Introduction
Clasification Society 2024 - Version 9.40
Clasifications Register Guidance Information - Guidance Notes for the Polar Class Vessel and Criteria for Non-Linear Analysis, January 2022 - Chapter 1 General - Section 1 Introduction

Section 1 Introduction

Parent topic: Chapter 1 General

1.1 Objective

1.1.1 The objective of this guidance note is to provide ship designers with guidance on using the non-linear finite element analysis method to evaluate the structural adequacy of grillage primary members supporting plating and framing in way of ice strengthening regions of ships assigned Polar Class (PC) notations to support local ice loads.

1.2 Background

1.2.1 The International Association of Classification Societies Unified Requirement concerning POLAR CLASS(UR I) is adopted into the Rules and Regulations for the Classification of Ships, July 2022. For determination of scantlings on load carrying stringers, web frames supporting local frames, or web frames supporting load carrying stringers forming part of a structural grillage system (hereinafter referred to as the grillage primary members), appropriate methods are outlined in Pt 8, Ch 2, 10.28 Direct calculations of the Rules and Regulations for the Classification of Ships, July 2022.

1.2.2  Pt 8, Ch 2, 10.28 Direct calculations of the Rules and Regulations for the Classification of Ships, July 2022 requires the grillage primary members to be assessed by direct calculations based on linear or non-linear analysis. The acceptance criteria for non-linear analysis is provided with high level goal given in Ch 1, 1.2 Background 1.2.3 , whereas same for linear calculation methods is provided with clear sets.

1.2.3  Pt 8, Ch 2, 10.28 Direct calculations 10.28.6 of the Rules and Regulations for the Classification of Ships, July 2022 requires the following to be considered:
  • The analysis is to reliably capture buckling and plastic deformation of the structure;
  • The acceptance criteria are to ensure a suitable margin against fracture and major buckling and yielding causing significant loss of stiffness;
  • Permanent lateral and out-of of plane deformation of considered member are to be minor relative to the relevant structural dimensions.

1.2.4 The aim of this document is to detail the process and criteria to be considered for compliance with Pt 8, Ch 2, 10.28 Direct calculations 10.28.6 of the Rules and Regulations for the Classification of Ships, July 2022.

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