Environmental testing resistance

Temperature plays a part in all environmental tests but it was convenient to separate into Chapter 15 those tests which are particularly concerned with thermal resistance alone and to consider here the other types of environment to which rubbers may be exposed. This includes resistance to liquids and gases other than permeability tests (permeability is covered in Chapter 17). 

Many environmental tests are accelerated because if they were not they would offer no advantage over a field trial. This introduces the problem seen with heat aging tests of satisfactorily extrapolating from short-term tests to long-term service conditions. When several environmental factors are present simultaneously, this difficulty is greatly increased. Extrapolation of accelerated environmental resistance data is discussed in Chapter 29. 

Environmental Testing, Aeronautical and Associated Equipment Fungus Resistance Tests Jolt Test for Use in Development of Fuzes Jumble Test for Use in Development of Fuzes 40-ft Drop Test for Use in Development of Fuzes Transportation Vibration Test for Use in Development of Fuzes... 

JIS C 0052-95. Environmental testing procedtrre of electronic and electrical resistance to solvents. 

Practice for Conducting Mixed Flowing Gas (MFG) Environmental Tests Standard Test Method for Resistance of Zippers to Salt Spray (Fog)... 

Efficiency of bio- and photosensitizers is established by the well-known biodeterioration methods of [68] fungal resistance (ASTM G21-70 or G22-76) environmental test methods and other biodeterioration test techniques (see also Chapter 19). 

Formation of Intermetallic Compounds. Increase of resistance after environmental tests... 

A paper by Hampel proposes a specification including the peel strength, the electrical resistance of the conductor tracks, and a series of environmental tests... 

By way of comparison, Jonsson et al. [6] used Kanthal AE and Kanthal AF as reference materials in their recent paper on Cyclic oxidation testing by resistance heating . The wire samples were U-shaped, 224 mm long and 0.7 mm dia. and therefore similar to the larger diameter wires used in this study. The samples were tested in constant power mode using a 2 min on/2 min off cycle at a power of 155 W (a peak surface load of 31.5 W/cm ). The temperature achieved at the hottest part of the sample was 1265°C. Such results agree well with the trends observed in this study, confirming our belief that this new rapid cycle, environmental test facility can test to the ASTM standard. 

For the failure analysis of the test samples after the harsh environmental tests, various analysis tools are employed, e.g., scanning electron microscopy (SEM) with a cross-sectional analyzing technique, x-ray microscopy, A-, B-, and C-mode scanning acoustic microscopy (A-SAM, B-SAM, and C-SAM, respectively), and tomographic acoustic microimaging (TAMI), to analyze the failure samples. The continuous measurement of the electrical resistance should consequently be conducted during all of the environmental tests mentioned above. 

ASTMD 1169-11. Standard test method for specific resistance (resistivity) of electrical insulating liquids. JIS C 0052-95. Environmental testing procedure of electronic and electrical resistance to solvents. 

Load Frame, Force and Strain Measurement, Data Acquisition The test method uses a standard load frame with a hydraulic or screw drive loading mechanism and standard force transducers. Force is applied transversely to produce a bending moment. Extension is measured by deflectometers in the gage section and strain is measured using bonded resistance strain gage rosettes to determine both longitudinal and transverse strains. If required, an environmental test chamber may be used to control humidity and ambient temperature. Data collection should be done with a minimum of 50-Hz response and an accuracy of 0.1 % for all data. 

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