Crack resistance testing procedures

Testing of metals for resistance to sulphide stress cracking at ambient temperatures Accelerated test procedures for screening atmospheric surface coating systems for offshore platforms and equipment... 

Fracture tests were conducted at a controlled ram displacement rate of 0.008 mm/sec. The load (P) vs. specimen deflection (5) curves were nonlinear, owing to plasticity and stable crack extension. Therefore, Landes and Begley s [ ] /-integral test procedure was applied to generate / resistance curves and //c data. 

Testing of Plastics - Instrumented Charpy impact test Procedure for determining the crack resistance behaviour using the instrumented impact test Part I Determination of characteristic fracture mechanics parameters for resistance against unstable crack propagation Part II Determination of characteristic fracture mechanics parameters for resistance against stable crack propagation... 

The requirement for stress crack resistance of the HDPE material used for geomembranes formulated in this way has been included in the BAM certification guideline for geomembranes in landfill liners (Muller 1992, 1999b) since it is based on genuine long-term tests. This evaluation procedure is very conservative since it assumes that the long-term available residual stress at an imposed deformation initiates a stress crack, in the same way as an imposed durable external stress does (see Sect. 5.4.1). 

Another test method, the so-called pin impression method, has been developed and standardised to test stress crack resistances of containers and packaging. The method is intended first of all to characterise the resistance under the influence of chemicals transported and stored in these containers. It has also been used for some time in the BAM certification procedure to test geomembranes for landfill liners (Muller 1992). 

Testing procedures for cracked concrete are essentially the same as used for other laboratory specimens exposed to chloride solutions continuously or cyclically. Methods that can be used include polarization resistance, electrochemical impedance, and macrocell corrosion which were discussed above. Procedures for conducting these tests are described in Refs 27 and 28. 

The procedures of ASTM B 117 and a modified version of ASTM G 44 were employed to study the behavior of solid brass fittings with that of coated and zinc-plated steel fittings. While G 44 was developed originally as an accelerated test for determining the chloride stress corrosion cracking resistance of aluminum and ferrous alloys, the concept of the alternate wet and dry cycling was considered relevant. 

Table A.17 provides the results of stress cracking resistance and chemical resistance tests. The stress cracking resistance of PMMA against a variety of media was evaluated using a test procedure similar to MIL 8184 (Section 2.5.5.2.1.3 [269]).

Environmental stress crack resistance (ESCR) is the ability of the material to resist long-term exposure to stress-cracking agents. Materials with ESCR values in excess of 1000 h are typically considered acceptable based on one of the common test procedures. 

Both devices described above were developed in order to test the friability of fluid-cracking catalysts. Nowadays the application of these or similar tests is a common procedure in the development of fluidized bed catalysts. Contractor et al. (1989), for example, used a submerged-jet test to compare the attrition resistance of newly developed VPO catalysts. In fact, such tests can be applied to any type of fluidized bed processes. Sometimes they have to be slightly modified to adapt them to the process under consideration. The drilled plate may, for example, be substituted by... 

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