Berechnung von Risseinleitung und Rissfortschritt in Hochtemperaturbauteilen

FKM 2002
Issue No. 273
Project No. 238

Abstract:
Calculation of crack initiation and crack propagation in high-temperature components IfW Darmstadt and MPA Stuttgart jointly carried out a project on crack initiation and crack propagation behavior under creep and fatigue loading on 1% CrMoNiV steels and 12% CrMoV steels for high-temperature components of thermal machinery and plant engineering. Applicable documents were provided for the assessment of creep cracking and creep fatigue cracking behavior in the component-relevant area and integrated into a modularly structured project No. 238 and creep fatigue crack initiation can be described by approximate description in the form of a two-criteria method. The stress intensity factor KI was applied to selected component geometries using available calculation rules. For creep crack initiation and creep crack propagation, documents were provided that support the parameter C* for the component-relevant 3D case. An accumulative description was created for the based on a description for the fatigue crack portion and a C*-dependent description for the. For the use of the crack initiation and crack propagation documents, experimentally verified values of crack initiation duration and crack propagation are available. For the final report, the creep and creep fatigue crack results were validated with the aid of FE calculations. For the conventional KI and C* evaluations of the test results determined on CT and DENT specimens, a crack tip widening criterion was defined for their validity. The comparison of the parameter C* has shown that ä -C* relationships such as the average crack length can be used. For the approximate determination of C2*, the experimentally measured v was used instead of the value Vc proposed in the EPRI manual. However, there is no influence on the tA-C*- and ä- determined in this way. 3D-FE- was carried out on selected cases to determine the parameter CFE* and factors between CFE* and C2* were determined. Work:
114 p. 01.07.1999 30.06.2002 AVIF-No. A141 Institute of Materials Science Technical University Darmstadt Prof. Dr.-lng. C. Berger Dr.-lng. A. Scholz Dr.-lng. J. Granacher Dr.-lng. T. Mao des Dr.-lng. J. Ewald, Mülheim Dr.-lng. E.h. J. Rabe, Höchstadt Staatliche Materialprüfungsanstalt Universität Stuttgart Prof. Dr.-lng. habil. E. Roos Dr .-Ing. K. Maile Dr.-lng. A. Klenk Dipl.-lng. T. Gengenbach