NAFEMS has already published several useful books explaining the theory of Finite Element Analysis (FEA) and how it is employed to simulate and analyse the behaviour of engineering structures and components. This publication is specifically designed to address the important issue of using the results of an FEA to substantiate a design.

With the advent of more powerful computers, the application of FEA has gained popularity among engineering companies involved in designing and analysing engineering structures and components. Design by analysis has become popular, but after each analysis, an assessment must be conducted to determine if the design has met its objective. Is it fit for purpose? Is it safe and reliable? Such evaluation is an important part of the overall design process and requires demonstrating compliance with relevant engineering codes and standards. Most of the designs, particularly their safety-related aspects, are reviewed for compliance with the rules specified in design codes and standards. These rules, meant to avoid certain known failures, were written well before the emergence of the FEA technology and relied on simplifying assumptions used in hand calculations. In these rules, additional factors are applied to account for effects that cannot be included in hand calculations. However, FEA models can and often do include most of these effects. Analysts who take FEA results and compare them against the code allowable may make a serious mistake of double-counting or miscounting an effect.

Furthermore, structural reliability methods are being introduced in modern design codes to account for uncertainties and assess the probability of failures, thereby minimising the risk. Load and Resistance Factor Design (LRFD, ANSI/AISC 360 [1]), Risk Informed Performance Based Design (RIPB, ANSI/ANS-30.3 [2]), and Limit State Design (LSD, [3] the Eurocodes) approaches are being used, where FEA plays a crucial role in predicting the performance of a design.

In summary, the book focuses on the following:

• the purpose of codes and standards in preventing failures,

• design code principles: allowable stress and limit state,

• failure modes and main effects to be considered,

• extracting the required information from FEA results: stress category and classification,

• differences in FEA and design code terminologies,

• design substantiation process,

• use of FEA in probabilistic design code assessments,

• FEA in integrated safety and design.

Readership

This publication is intended for engineering students and simulation engineers who are familiar with the finite element method and its associated terminology. It is assumed that the reader is familiar with structural design codes and has a basic understanding of the various failure modes associated with material yielding, collapse, buckling, fracture, and fatigue, which can compromise the structural integrity of a structure or component.

The publication aims to offer an understanding of how the rules in the codes and standards are used to prevent specific known failure modes. Examples illustrate how FEA can simulate the effects of loading, which are often overlooked in simple hand calculations, and how practising engineers can use FEA results to meet the requirements of design rules in industry codes and standards aimed at preventing failure modes.

Appropriate references are made to NAFEMS publications on FEA, as the emphasis here is on using the results of an FEA, not on performing an FEA.

Scope

The scope of this book is essentially restricted to the structural mechanics area and the use of FEA in addressing structural integrity issues for the safe design of engineering steel structures and pressure vessels. It addresses codes and standards based on either allowable stress or limit state principles.

Content

International Standard Book Number: 978-1-83979-239-7
First Published: 2025