13th International Conference on Fracture June 16–21, 2013, Beijing, China -2- on the basis that they are validated with experimental data. In this paper an outline of geometries that have been tested in a number of EU programmes are identified and the differences in method of analysis using the fracture mechanics parameter C* in laboratory and components will be highlighted and compared for a pipe and plate component. 1.1 Background to life assessment codes Components in the power generation and petrochemical industry operating at high temperatures are almost invariably submitted to static and/or combined cycle loading. The alloys used can vary between low carbon steels to high chrome superalloys with various alloying contents. In addition these components have welded parts which will have different alloying and microstructural properties. The failures can be due to large deformations, creep rupture and/or crack growth. The development of codes in different countries has moved in very similar direction and in many cases the methodology has been borrowed from a previously available code in another country. Early approaches to high temperature life assessment have used methodologies based on defect-free assessment codes. For example ASME Code Case N-47 [9] and the French RCC-MR [10], which have many similarities, are based on lifetime assessment of un-cracked structures. More recent methods make life assessments based on the presence of defects in the component. The more advanced codes dealing with defects over the range of creep and creep/fatigue interaction in initiation and growth of defects are the BS 7910 [11], British R5/R6 [12,13], the API RP 579 [14] and the French A16 [15] which have clear similarities in terms of methodology. It is also obvious from these assessment methods that the correct evaluation of the relevant fracture mechanics parameters, for which the lifetime prediction times are dependent upon, are extremely important. It is also evident therefore that the detailed calculation steps, which are proposed in these documents alone, do not improve the accuracy of the life prediction results. In any event as these procedures have been validated for limited sets of geometries and ‘Benchmark’ material data, their use in other operating conditions will need careful judgment. These aspects have been considered in this paper in order to produce validated fracture mechanics parameters form different geometries for this purpose. The paper highlights recommendations for improved test methods so that verifiable material properties are collected. This allows the modelling methods using standard laboratory and feature component data to be used with increased confidence in life estimation codes. This pre-standardisation work is of relevance to ASTM, ISO, ASME, API (American Petroleum Institute) and PVRC (Pressure Vessels Research Council (USA)) as well as to allow further improvements to life assessment CoP such as R5, BS7910 and A16. Clearly the recommendations resulting from this CoP will be useful for increasing confidence in defect assessment codes. 2 Parameters for Analysing High Temperature Cracking Typically, fracture mechanics concepts are used to characterise crack initiation and growth at high temperatures. Usually at short times the stress intensity factor K, or the elastic-plastic parameter J, is employed to describe the stress and strain distributions at a crack tip whereas at long times, when
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