STYLE: Transferability of Fracture Material Properties - Updated Experimental and Analytical Results

Abstract

This paper describes new results of the STYLE study on investigations of transferability of fracture material properties obtained by testing of small scale specimens to a real component. In STYLE there are three large scale mock-up tests each of them dedicated to investigate specific effects. Mock-up3 (cladded ferritic pipe with the outer diameter of 424 mm) is foreseen to investigate transferability of material data, in particular to compare fracture mechanics behavior of small specimens under different constraint conditions with a full size component. The Mock-Up3 is an original part of a surge line made of low alloy steel (20MnMoNi55 which corresponds to SA 508 Grade 3, Cl. 1). Usually, material data necessary for fracture mechanic analyses are obtained by testing small specimens, which are subsequently used for the assessment of large scale structures (real components). This approach is believed to be conservative since the material properties are obtained on highly constrained standard specimens. In this paper new experimental and analytical results will be presented (including tests on constraint modified specimens and a comparison of these results with the Mock-up3 test). The overall objective is to investigate the influence of specimen size, crack shape and type of loading on fracture mechanics properties like crack initiation load or amount of the crack growth by means of numerical analyses and compared with experimental results.