Degradation accelerated life testing

Comparing to the accelerated life test where only the life distribution under a given stress level is recorded, the accelerated degradation test keeps track of the evolution of a damage metric (Fr), which allows the experimental validation of the correlation approach if the selected damage metric is observable. For example, the projected life distribution under normal stress can sometime... 

Degradation models for system components may be determined by accelerated life tests and then used after online fault diagnosis has identified the initiation of an incipient fault in order to assess the health of a system and to predict the RUE of the component with an incipient fault [8]. 

In the future, underwater acoustic system research should be designed to identify the mechanisms of bond degradation and to develop accelerated life testing methods and long-term predictive capability. 

Clearly, finding a single accelerated-life-test to evaluate materials against all the possible environmental hazards and materials degradation mechanisms is unrealistic. Each material or device needs to be evaluated by a series of tests to elucidate its possible degradation processes. Experience has shown that our ability to predict what test to use when field failure data are not available falls well short of needs. In reality, the corrosion engineer must rely on past experience to make an educated judgment about potential failure scenarios and which accelerated-life-tests to run. 

While this degradation process was discovered by accelerated-life-testing and discussed in the literature almost 20 years ago (Lahti et al., 1979 Lando et al., 1979), the authors have never observed or been told of a field failure due to conductive anodic filaments. This testing served to alert designers to the need to ... 

Keywords Service-life prediction Real-world validation Degradation pathways Degradation-rate model Accelerated life testing Cumulative damage model... 

Finally, the multiple SLP models examined in this work all yielded essentially the same lifetime estimate. The principal model put forth in this study, based on Eqs. (2.1) and (2.2), analyzed the entire absorbance degradation curve of the fluorescent vinyl film. In contrast, analysis via the accelerated life test model [Eq. (2.5)] targeted a single point—the value of tp at which the absorbance of the film reached... 

The existence of this relationship offers the advantage of universality, in that the accelerated life test model can be applied in cases where derivation of a mathematical expression for the degradation of the property of the material under investigation is not straightforward. 

The foregoing requirements that determine the applicability of the accelerated life test model to SLP estimation demand an understanding of the degradation pathways involved. Several supplementary experiments were conducted in order to elucidate the pathway(s) corresponding to loss of 455-nm absorbance in the fluorescent yellow vinyl film that served as the model material in this study. In addition to those... 

Degradation-rate model Accelerated life testing Cumulative damage model... 

Fig. 13.16 Qualification of the moisture resistivity of two modules with different degradation processes resulting in different time-to-feilure and different activation energies for three different climatic stress conditions. The longer time to failure in accelerated life testing for the module indicated in red does not result in better durability in operation compared to the second module...

ABSTRACT This paper described the general process of Accelerated Life Test and its limits in use of satellite electronic instrument briefly analysis several accelerated life test methods based on failure rate, empirical formula, accelerated degradation and transformation proposes accelerated life test method based on activation energy estimate forecast, provided a new way for ALT of satellite electronic Instrument, and validated its applicability. Subject results promote the use of other satellite electronic instrument. 

A comparison between the accelerated tests and the operational life tests provides an acceleration factor . A major concern in accelerated life tests is to be sure that you are accelerating the right degradation mechanism. Most often both life tests and accelerated tests are run. In addition, control samples (shelf samples or archival samples) are kept in pristine condition so that aged samples can be compared to the original materials. This type of test has... 

The kinetics of degradation processes in foodstuffs are not simulated by the accelerated shelf-life testing method in the same way. Different parameters like Uw value, pH value, acidity levels, sulphur compounds, etc. affect flavour degradation in the foodstuff very individually therefore, a careful transfer of results is absolutely essential. The tested products have to be clustered depending on their ingredients and parameters for the accelerated testing have to be adapted (Fig. 21.10). 

Shelf Life. Encapsulated orange oil samples were subjected to accelerated shelf life testing at 37 ad 50 C. Control samples were stored at 25 C. The samples were evaluated until degradation was sufficient to produce a level of 2 mg... 

Figure 25. Concept of accelerated life and accelerated degradation test T1 and T2 are two stress levels and T3 is the normal stress level PI, P2, and P3 are the life distribution under stress level Tl, T2, and T3.

Figure 2.1 Accelerated stability testing. The percentage of drug remaining at elevated temperatures with time is measured (left) and the rate constants for the degradation reaction calculated. Using the Arrhenius relationship, a plot of the log of the rate constant against the reciprocal of absolute temperature of measurement yields a straight line (right). Extrapolation of the line permits calculation of the rate constant at lower temperatures and the prediction of shelf life.

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