Stress cracking potential evaluation

Figure 8. Simple apparatus for evaluating stress cracking potential of candidate membrane materials.

Injection molded parts are known to degrade under the influence of UV or chemical environment (environmental stress cracking) at certain areas of stress concentration. Release agents may play certain role in these processes because they may help to release part before its core has solidified. Also, uneven distribution of release agent on surface may induce tension into a part skin. Any internal stress potentially increases risk of material degradation, under the influence of radiation or contact with solvents. The essential parameters, which contribute to stress formation, are evaluated in a broad research study. ... 

The most important goal for each NASA-developed CMC system was to be able to operate under potential component stress levels for long time at its selected upper use temperature (UUT). To evaluate this capability, tensile test specimens from the various CMC panels were subject to creep-rupture testing in ambient air at their goal UUT and at stresses of -60% of their room-temperature cracking stress. The primary performance objective was to demonstrate greater than 500-hour life without specimen rupture. Since high-temperature mpture of an initially uncracked CMC is typically controlled by CMC... 

Some boilers are equipped with an embrittlement detector by means of which the chemical treatment of a water can be evaluated continuously in terms of its potential ability to induce stress-corrosion cracking (Fig. 18.3) [13]. A specimen of plastically deformed boiler steel is stressed by setting a screw adjustment of this screw regulates a slight leak of hot boiler water in the region where the specimen is subject to maximum tensile stress and where boiler water evaporates. A boiler water is considered to have no embrittling tendency if specimens do not crack within successive 30-, 60-, and 90-day tests. Observation of the detector is... 

The elastico ML has potential for many sensing and imaging devices such as stress sensor, visualization of stress distributions in solids, visualization of stress distribution near tip of the crack, visualization of quasidynamic crack propagation in solids, visualization of defect in pipe, light sources, mechanical evaluation of orthopaedic devices like artificial legs, ML-based health monitoring system, etc. 

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