Cyclic tests

Boyce, M.P., and Herrera, G., Health Evaluation of Turbine Engines Undergoing Automated FAA Type Cyclic Testing, Presented at the SAE International Ameritech 93, Costa Mesa, California, September 27-30, 1993, SAE Paper No. 932633. 

Cyclic tests can be perfonned in just a few months to simulate years of fill and discharge cycles. The adsorbent filled ANG tank is repeatedly charged with natural gas to a preset pressure, then discharged through a flow meter to determine the quantity of gas delivered from each cycle. 

Cyclic Test Unit Filter Evaluations", Report to Future Fuels Inc., Oct. 1987, Alcohol Energy Systems, California. 

Table 7.8 Oxidaiioil resistance of a nuibber of steels as shown by a short time, cyclic test...

Lithium perchlorate-dioxolane electrolyte systems are unsafe for secondary battery applications, as an explosion occurred during overnight cyclic testing of a Li/TiS2 system. The effect was duplicated under all over-discharge or cell-reversal conditions. 

Post-installed bolts will be required at times for attachment of equipment which may be subjected to large accelerations during a blast. Expansion anchors should be avoided for most blast design applications unless the load levels are low. Typically "wedge" type anchors are qualified for dynamic loads although most of these ratings are for vibratory loads and are based on cyclic tests at low stress levels. These should only be used where ultimate loads are less than the rated capacity with a margin of safely. Epoxy anchors have shown excellent dynamic capacity and may be considered for critical applications. 

Dynamic properties are taken to mean the results from mechanical tests in which the plastic is subjected to a deformation pattern from which the cyclic stress-strain behaviour is calculated. These do not include cyclic tests in which the main objective is to fatigue the material. 

Proper selection of the extractant as well as the other solvent components can minimize emulsions and crud formation. Freshly prepared solvents can often contain impurities that could subsequently cause operational problems. Therefore, all solvents should be conditioned before use. Ftaving selected a suitable solvent system, cyclic tests should be performed to determine whether degradation of any of the solvent components is taking place, as any degradation products could cause crud formation in the circuit. 

Accelerated Corrosion Tests. There are as many as a dozen methods (salt fog, Kesternich, etc.) that are currently being used to investigate corrosion resistance of coating systems and a need to develop a better and more dependable method to predict in-use service. A severe drawback of all these tests is that their results often compare unsatisfactorily with practical experience. One reason for the discrepancies is assumed to be the variability of natural exposure conditions. Accordingly, cyclic testing procedures have been developed with which exposure conditions, especially temperature and humidity. 

An important aspect is involved in large deformation cyclic tests it is related to the amount of damage done in each cycle which may accumulate in a predictable fashion but which also depends on conditions which may allow recovery. These items will be discussed later. 

The term dynamic test is used here to describe the type of mechanical test in which the rubber is subjected to a cyclic deformation pattern from which the stress strain behaviour is calculated. It does not include cyclic tests in which the main objective is to fatigue the rubber, as these are considered in Chapter 12. Dynamic properties are important in a large number of engineering applications of rubber including springs and dampers and are generally much more useful from a design point of view than the results of many of the simpler static tests considered in Chapter 8. Nevertheless, they are even today very much less used than the "static" tests, principally because of the increased complexity and apparatus cost. 

Another important factor for tensile testing is cyclic testing or applying force and releasing (or relaxing) force on a test specimen to evaluate its ability to endure cyclic fatigue. A typical stress vs. strain relationship is shown in Fig. 3.16 and a cyclic stress relationship in Fig. 3.17. 

Rmax Maximum stress intensity factor (MPa m1/2) (cyclic tests)... 

Rajagopalan et al [30] confirm that methods involving cyclic redox aging of metals in the presence of sulphur are needed for screening metals tolerant catalyst. A simplified cyclic test (cyclic propylene steam) method is proposed which addresses the redox ageing of the metal, but not the non-uniform laydown and age distribution of metals on the catalyst. 

The adhesive should be selected on the basis of durability as defined by slow cyclic testing in a hot and humid environment. 

During the course of a cyclic test, some changes in the coefficient of friction may arise as a consequence, for example, of the development of physicochemical interactions between the contacting surfaces. For glass in contact with glassy polymers such as poly(methylmethacrylate) or epoxies, an in-... 

Absorption of SO2 and SO3 (Equations 1 and 2) is very rapid. For example, in the laboratory when pure SO2 is bubbled through 2 inches of melt, no odor of SO2 can be detected in the exit gas (CO2). The presence of O2, CO2, N2, H2O, and fly ash does not aflFect the SO2 removal. Melt which was regenerated 3 times in a series of cyclic tests was equally effective in removing SO2. These results are not surprising in view of acid-base considerations in which the acidic SO2 is neutralized by the basic alkali carbonate melt. 

Typical destructions of standard eye specimens after fatigue tests are shown on fig. 3. During the process of cyclic tests of the eye specimens the fatigue cracks initiated on the surface of holes of 20 mm in diameter (stress raisers) and propagated outward to the external part of the specimens. 

Young s modulus, and fracture energy was collected. The tensile tester was also programmed to perform a cyclic test. Samples were repeatedly stretched to 2 % strain at 50 mm/min and back to 0% strain. A total of 5 cycles were tested and the peak stress was recorded for each cycle. 

Sufficient material to perform the safety analysis and cyclic testing will be prepared by ball milling utilizing a composition of 2m% TiCl3 catalyzed NaAlH4, designated CCH 0. 

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