Life prediction

BE-3019 A methodology for life prediction and condition assessment for welds of Mr. A.A. BetisU EDPSA... 

Hansen L D and Hart R M 1978 Shelf-life prediction from Induction period J. Electrochem. Soc. 125 842... 

Bolotin, V. V. 1994 Fatigue Life Prediction of Structures. In Spanos, P. D. and Wu, Y. (eds). Probabilistic Structural Mechanics Advances in Structural Reliability Methods. Berlin Springer-Verlag. 

J. C. Newman, Jr. A Review and Assessment of the Stress Intensity Factors for Surface Cracks," Part-Through Crack Fatigue Life Prediction, ASTM STP 687, J.B. Chang, Ed, American Society for Testing and Materials, 1979, pp. 16 42. 

T. Hoshide, K. Kusuura. Life prediction by simulation of crack growth in notched components with different microstructures and under multiaxial fatigue. Fatigue Fract Eng Mater Struct 27 201, 1998. 

Ford, F. P., Modelling and life prediction of stress corrosion cracking in sensitized stainless steel in high temperature water , Proc. of ASME Fall Meeting, 1985... 

In mechanistic studies of stress corrosion and also in the collection of data for remaining-life predictions for plant there is need for stress-corrosion crack velocity measurements to be made. In the simplest way these can be made by microscopic measurement at the conclusion of tests, the assumption being made that the velocity is constant throughout the period of exposure, or, if the crack is visible during the test, in situ measurements may be made by visual observation, the difficulty then being that it is assumed that the crack visible at a surface is representative of the behaviour below the surface. Indirect measurements must frequently be resorted to, and these... 

Altshuler, T. L., Fatigue Life Predictions for Materials Selection Guide, ASM Software, 1988. 

We are pleased to acknowledge our indebtedness to colleagues P. J. Baldock and A. Parker for the x-ray crystallographic studies, to P. Snowden who devised the life prediction technique, and to Imperial Chemical Industries Ltd. for permission to publish this paper. 

Recent Advances in Fatigue Life Prediction Methods for Rubber Components... 

Mars, W.V., Heuristic approach for approximating energy release rates of small cracks under finite strain, multiaxial loading, in Elastomers and Components—Service Life Prediction Progress and Challenges, Coveney, V., Ed., OCT Science, Philadelphia, 2006, 89. 

Mars, W.V. and Fatemi, A., Multiaxial fatigue of rubber Part 11 experimental observations and life predictions. Fatigue Fract. Eng. Mater. Struct., 28, 523, 2005. 

Thomas, R. E. Gaines, G. B. "Procedure for Developing Experimental Designs for Service Life Prediction" Thirteenth Institute of Electrical and Electronics Engineers, Inc. Photovoltaic Specialists Conference, Washington, D.C., June 5-8, 1978. 

This book covers what are broadly called plastics materials. Composites based on long fibres and thermosetting resins are mentioned but not studied specifically. Elastomers, coatings, textiles and adhesives are generally excluded but attention is drawn to a companion volume on the life prediction of rubbers [1]. 

Ideally the report would cover remanent life prediction, that is the intermittent inspection of a component and the re-assessment of its probable lifetime based on past service history and its physical or chemical condition the materials analogy of a pensions actuary making his estimate of the likely dates of death of his human charges. Probabilistic remanent life prediction... 

Not surprisingly, life prediction is particularly difficult for components that degrade by the most complex chemical mechanisms. 

The degradative mechanisms in plastics have been described in detail [1, 2]. This section will outline the agents and basic mechanisms of degradation and identify those which are most significant for life prediction. 

Table 4.1 lists the principal degradation agents and their consequences. The sections that follow explain the mechanisms and their effects in more detail. The rates at which degradation occur, which provide the basis for life prediction, are discussed in Chapter 8. 

Usually, there is more than one degradation agent present, giving a more complicated situation. For the purposes of life prediction it is desirable, wherever possible, to identify the critical degradation agent for the particular application or the particular objective. 

The respondents who showed the most interest in life prediction were cable manufacturers, electrical distribution authorities, gas distribution authorities, nuclear power station designers and operators, and the aircraft industry. Interest was less, but nevertheless increasing, among the manufacturers of small electronic and electrical equipment and computers, many of whom use polymers principally for housings and similar components. 

Although in most applications no assessment is made unless a component fails prematurely, many respondents to the survey mentioned above reported that they examine and analyse polymer components taken out of service at the end of their service lives. In this way they could establish directly whether the components were still fit for use, and could feed this back to validate the process of life prediction at the design stage. Such information is generally retained within a company, but it was gratifying to learn that this practice is more common than was thought. 

This book is concerned with assessing the useful life of plastics and accelerated testing follows service experience and simulated life tests in importance as a basis for life prediction. However, the results of accelerated tests are not always used to predict service life directly. Indeed, the majority of accelerated tests are carried out for quality control purposes, to show conformity with a specification or to make a comparison of materials. 

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