From thermal cracking, elemental analysis

Since the formation of maincrack could be observed at the AE increasing point, it is understood that the remarkable increase in AE corresponds to the main-crack formation due to microdamage accumulation. Then the critical stress for maincrack formation during thermal shock fracture, oth, can be determined by Disk-on-Rod test. Those values ranged from 220 to 330 MPa. The instantaneous crack path was not determined definitely because of its high growth velocity. Therefore, the thermal stress analysis is no longer valid after maincrack formation because the crack path could not be introduced into finite element models. 

The subject of this paper is a selected piece from a wider research program concerning thermal shock damage. The activities include the fracture analysis of multiply notched strips under thermal shock as well as experiments to produce thermal shock crack patterns. The calculations involved analytical, finite element and boundary element methods. The results have been published recently [4,5]. Their immplications for the thermal shock damage criteria, including the reproduction of Hassel-man s results, have been discussed earlier [6,7]. 

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