SAFESA Quick Reference Manual

NAFEMS

First Published - January 1995
Softback, 19 Pages

This document sets out the basis of the SAFESA methodology for the use of finite element analysis is to support the qualification of engineered structures. The philosophy adopted in SAFESA is to formalize the process of structural qualification. The objective is to minimize the opportunity for error – especially in regard to the idealization process. To this end, SAFESA provides a systematic procedure (or framework) for carrying out finite element analysis within a qualification. The framework in itself should help to minimize error, and also provides a means of identifying and treating errors.

SAFESA is based on current best practise. Experienced practitioners will find few surprises and hopefully much with which they agree within the document. It is relevant to anyone using finite element analysis to check the integrity of engineered structures and should find use within the aerospace, building, civil, offshore, defence manufacturing, nuclear, process and shipbuilding industries for example. As the SAFESA Quick Reference Guide is not aimed at any particular industry it has been necessary to generalize some of the concepts and practises unique to certain industries. Also, some of the terminology may appear to be somewhat convoluted on first acquaintance. Words ascribed particular meaning are shown underlined when first used and are explained further in the Glossary.

For experienced analysts and those already familiar with SAFESA, this document serves as a summary reference to the SAFESA Technical Manual. Readers unfamiliar with SAFESA are advised to start with the summary in Section 2. Section 3 then provides a summary reference for ‘Defining the scope’ of a structural qualification and Section 4 introduces the process of ‘Idealization’ and outlines the relationship of the remainder of the detailed assessment to idealization.

This document is supported by a number of other documents, including ‘The SAFESA Management Guidelines’ [1] and the ‘SAFESA Technical Manual’ [2] and broadly supports recent quality standards such as ISO 9001 [3] and the NAFEMS QSS [4].

Contents

INTRODUCTION

SUMMARY OF THE SAFESA APPROACH

• Defining the Scope (Stage 1)
• Detailed Assessment (Stage 2)
• Qualification Conclusions (Stage 3)

STAGE 1 – DEFINING THE SCOPE

• Stage 1.1 – Initial description of the real structure
• Stage 1.2 – Problem overview
• Stage 1.3 - Structural issues
• Stage 1.4 – Analysis approach
• Stage 1.5 – Structural model
• Stage 1.6 – Creation of validation plan
• Stage 1.7 – Review and approval

STAGE 2 – DETAILED ASSESSMENT

• Stage 2.1 – Idealization
• Stages 2.2 to 2.8 – Relationship of other stages of the detailed assessment to idealization

APPENDIX A – Idealization and Error Assessment Summary

• Stage 2.1.1 – Global boundaries ad loading actions
• Stage 2.1.2 – Global load paths and geometry
• Stage 2.1.3 – Structure sub-division
• Stage 2.1.4 – Boundaries and loading actions for features
• Stage 2.1.5 – Load paths and geometries for features
• Stage 2.1.6 – Preliminary error assessment / planning
• Stage 2.8.1 – Follow-up error assessment
• Stage 2.8.2 – Test programme
• Stage 2.8.3 – Experience Data

APPENDIX B – Idealization Error Sources and their Treatment

APPENDIX C – Glossary

APPEDIX D - References