Accelerated testing methodology

Accelerated Testing Methodology for Lead-Free Solder Interconnects... 

Accelerated Testing Methodology for Polymer Composite Durability... 

ISO 15686-2 describes the methodology of estimating service lives based on experience, short-term measurement and accelerated testing, in that order. All possible degradation agents and their intensities are listed. Methods for evaluation and for pre-testing (control... 

Suggesting and carrying out an accelerated reha-bility test of item is another option. This proposal was accepted by the producer and after the test proposal and designing the test structure it has been in the phase of its performance. A structure and a basic description of the test methodology are introduced below. As the... 

In equation 5, nj is the number of cycles within a block applied at stress level aj and Nj is the total number of cycles to failure at that stress level (obtained from the a-N curve). If validated for a particular material, equation 5 can be used for any arbitrary loading condition. In this way, the fatigue data generated in the laboratory is referred to as an accelerated test and equation 5 is used much in the same way that time-temperature superposition is used to predict the viscoelastic deformation of a material. Note, however, that any predictive methodology like that presented in equation 5 must be validated before it is employed for lifetime estimates. In the case of Minor s law, the sequence of the loading history should have no effect on the total lifetime. That is, if one specimen is loaded for a selected portion of its life at stress level stress level ct2 followed by CTi. 

AISI [I2-/4] luis taken a leadership role to develop and evaluate methodology based on laboratory experiments, field exposure history, and theoretical and empirical models through an open forum of all interested parties (mainly North American automotive and steel industries), organized as the Corrosion Task Force of the AISI. The task force developed an improved laboratory-accelerated test for ranking the cosmetic corrosion resistance of coated automotive steel sheet products. This approach serves as a model for methodology development in areas of nonmetaUic coatings corrosion testing. 

Ideally, the results of both site monitoring and accelerated tests in combination are expected to provide the best basis for the prediction of long-term durabihty and lifetime. However, a consistent methodology to combine both approaches still needs to be developed (Fig. 21.5). 

Reliability of electronic assemblies is a complex subject.This chapter has touched on only one aspect of the problem understanding the primary failure mechanisms of printed circuit boards and the interconnects between these boards and the electronic components mounted on them. This approach provides the basis for analyzing the impact of design and materials choices and manufacturing processes on printed circuit assembly reliabihty. It also provides the foundation for developing accelerated testing schemes to determine reliability. It is hoped that the fundamental approach will enable the reader to apply this methodology to new problems not yet addressed in mainstream literature. 

This paper outlines how this quantitative weathering model can be used, first to better understand the linkages between natural and accelerated testing and, second, to predict outdoor gloss and color retention, as well as chalk resistance, for waterborne coatings based on new PVDF-acrylic hybrid latex materials. A general methodology for this approach is depicted in Fig. 5.1. 

There are also many papers considering methodology for prediction of lifetime from accelerated tests (for example (50, 61, 62) and this has been considered comprehensively in a guide to lifetime prediction (17). Stevenson (54) refers to costly mistakes having been made in critical offshore applications, from which the appropriate lessons have not always been learned, and considers some of the applications and the material evaluation requirements. 

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