Accelerated tests purpose

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. 

It is important that the purpose of any accelerated test programme is clearly established, because this has a large bearing on the design of the trials and the interpretation of the results. As a generality, tests where the objective is to make direct predictions from the results are a great deal more difficult to design and will be considerably more costly than tests for the other purposes. 

Heat ageing tests are carried out for two distinct purposes. They can be intended to measure changes in the plastic at the elevated service temperature, or else as an accelerated test to estimate the degree of change which would take place over longer times at lower temperatures. Here, we are concerned with the second purpose. 

Uj) Telemetry Tests (Low Spin and Low Acceleration). The purpose of these tests is to investigate the performance of fuzes used with ammunition of low acceleration and spin parameters, such as the recoilless rifle and mortar projectiles. The techniques require the use of FM transmitters potted into the projectiles for transmitting such information as switch closure and electrical charge generation in flight. The telemetry transmitting station, like the transmitter in the round, are both assembled from std radio components modified for these particular tests (p IIIB-22 of Ref 39)... 

The purpose of an accelerated aging test is to duplicate the physical and chemical changes occurring naturally in a aiaterial in a relatively short time frame so that the useful life of the material can be assessed. Therefore, the conditions of an accelerated test must be adequate for the satisfactory duplication of the degradatlve processes and not conducive to the Initiation of degradatlve reactions that do not occur ordinarily at ambient conditions. 

Accelerated testing of the protective ability of the preservation of hardware by inhibited plastics is carried out by standard methods at the branch, state or international level. The real conditions of storage and transportation of preserved articles are simulated during these tests. With this aim, the system is subjected to a cyclic loading with a salt mist in dry or wet conditions with [87-89] and without moisture condensation [86]. Aside from this, certain simplified non-standardized procedures take into account the type and purpose of preserved hardware as well as the required conditions, aims and terms of preservation [49-51,90-92]. 

The protective properties of inhibiting films are estimated periodically. With this aim, standard as well as purpose-developed methods of accelerated test can be used (electrochemical, microbiological, model). These tests may be time consuming and are rather laborious. 

Whereas the standardized accelerated tests emphasize robustness and reproducibility in performance, a number of important accelerated tests have been developed for scientific purposes that emphasize... 

Accelerated tests in the melt can be used for quality control purposes, with a constant polymer/stabilizer system, but they do not permit selection of a stabilizer formulation with respect to its performance under actual use conditions. 

Accelerated testing Tests conducted at higher stress levels than normal operation but in a shorter period of time for the specific purpose to induce failure faster. 

Abstract This chapter provides an overview of extensive research conducted by the Vinyl Siding Institute (VSI) on the development of new test methods for exterior plastic building products. The purpose of the VSI study was to develop an accelerated testing protocol for use in certifying materials. 

For the purpose of evaluating the life and reliability indexes of servo valve, both simulation test and accelerated test are conducted before that is put into use. The information obtained from the two tests are used for life prediction modelling according to the procedure in Section 3.1 and 3.2. The results are shown in Figure 5. At first, the wear of nozzle flapper and sliding valve under the influence of oil pollution is simulated through... 

According to (Escobar 2006), Accelerated Tests (ATs) is a term used for two completely different kinds of tests with different purposes, qualitative ATs and quantitative ATs . The key differences are presented briefly in Figure 1. 

Field return data can be used for variety of purposes that include the prediction of future claims, the estimation of field reliability, and the identification of opportunities for quality and reliability improvement. (O Connor Kleyner, 2011). If one assumes that the return data is error free then it is not difficult to claim that it is the most trustworthy data in analyzing reliability of a product compared to accelerated test or simulation based data. However, in reality field return data contains errors corresponding to improper, correlated, incomplete, and poorly collected data that result in misleading reliability predictions. In this study, we first deal with this problem. We propose a systematic approach to eliminate errors from field... 

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