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The incorporation of reliability theory into a fatigue analysis algorithm is studied. This probabilistic approach gives designers the ability to quantify “real world” variations existing in the material properties, geometry, and loading of engineering components. Such information would serve to enhance the speed and accuracy of current design techniques. An automobile wheel assembly is then introduced as an example of the applications of this durability/reliability design package.

Three computer programs are presented for predicting the fatigue life of notched members undergoing complex load histories. The programs, while differing in terms of required information, employ a common approach involving the determination of the material response at the notch root, an assessment of damage based on closed hysteresis loops, and a linear damage summation to predict life. Agreement between predictions and experimental results generated by the SAE Fatigue Design and Evaluation Committee is reasonably good. The programs have purposely been kept simple to allow for easy modification. Applications and limitations of the three programs are discussed.

Substantial improvements have been made in the accuracy of component fatigue life predictions through the incorporation of cyclic stress-strain concepts in fatigue analysis procedures. This paper describes recent advances in material characterization, complex history analysis and notch analysis, and their application in computer-aided fatigue analysis procedures. A simplified strain-based approach, which offers conceptual and computational advantages, is then described and shown to be useful in many ground vehicle problems. Finally, several applications of these techniques in engineering design practice are presented.

A new section on fatigue properties of metals is currently being written under the guidance of the SAE Fatigue Design and Evaluation Committee. This paper presents a preliminary copy of the proposed section which includes an introduction, a table of monotonic stress-strain properties, a table of cyclic stress-strain and fatigue properties, definitions of properties, and an example application. The main purpose of the paper is to provide engineers with the available data at the earliest possible time. The final version of the report will be published in the SAE Handbook.

An overview of the basic concepts involved in performing a fatigue analysis is presented as an introduction to a series of specialized papers dealing with the development of fatigue information and its use in engineering design. Following a brief account of the fatigue process and failure definition, methods for describing fatigue resistance are discussed. Cumulative damage concepts based on fatigue life curves are then demonstrated.

Significant progress in materials and structures research leading to improved analytical and experimental capabilities for evaluating the mechanical durability of automotive structures is reviewed. Recent experiences in incorporating modern fatigue analysis methodology in easily used computer-based formats are then presented. This is followed by a general discussion of the application of design aids at various points in the product development cycle with emphasis on future trends and needs.

An overview of the current status and emerging trends in durability-related technologies is presented as an introduction to a series of papers covering applications of durability analysis in design. Problems of information management associated with technology integration are discussed along with the probable impact of new design tools on product development and validation.