Metallic components in nuclear engineering are exposed to extensive loads such as pressurization and temperature changes which can affect the properties of the material significantly depending on the load spectrum applied. In view of developing a procedure to evaluate the residual service life of metallic components in nuclear power plants aged during service, metastable austenitic steel AISI 347 (German designation: X6CrNiNb18−10) has been considered as an example. To this purpose, total strain-controlled fatigue tests were carried out under different environmental conditions and monitored by continuously measuring thermometric, resistometric, electromagnetic and electrochemical parameters. These parameters provide an information gain in terms of material characterization when compared to conventional strain measurements. Based on these parameters, the short time evaluation procedure StrainLife has been developed, which allows the determination of local S-N curves with a significantly reduced effort as compared with traditional procedures. This method has been implemented into the structural simulation program PROST for the integrity assessment of the components while considering local fatigue properties. This very effective method allows for the determination of local fatigue properties including the strain-specific local scatter of the metallic microstructure properties of the material which has not been possible by traditional means.

123 Production-and microstructure-based fatigue assessment of metallic AISI 304/430 multilayer materials produced by hot pack rolling B. Mitevski, S. Weiß and A. Fischer 130 In-situ tensile testing of notched poly-and oligocrystalline 316L wires 136 Effect of processing conditions on the structure, electrical and mechanical properties of melt mixed high density polyethylene/multi-walled CNT composites in compression molding S. Gach, A. Schwedt, S. Olschok, U. Reisgen and J. Mayer 148 Confirmation of tensile residual stress reduction in electron beam welding using low transformation temperature materials (LTT) as localized metallurgical injection-Part 1: Metallographic analysis T. Srinivasa Rao, G. Madhusudhan Reddy and S. R. Koteswara Rao 155 Investigation on variations in hardness and microstructure of in-process cooled 7075 aluminum alloy friction stir welds M. Farajian, V. Hardenacke, W. Pfeiffer, M. Klaus and J. R. Kornmeier 161 Numerical and experimental investigations on shot-peened high-strength steel by means of hole drilling, X-ray, synchrotron and neutron diffraction analysis G. Sun and Z. Zhou 166 Ultrasonic imaging of particle distribution in SiCp/Al composites 183 Finite element analysis of a vibration test bed frame J. Gülen and M. İskeçeli 188 Removal of methylene blue by using porous carbon adsorbent prepared from carbonized chestnut shell

Pressurized pipes in hot water environment are subject to ageing mechanisms such as fatigue and environmental-assisted fatigue. These ageing effects limit the in-service time of components due to the possibility of crack formation, initiation and growth. Furthermore, uncertainties in life time assessment evolve as a consequence of increased scattering and resulting deviations in material properties. The lack of appropriate information requires safety-oriented design and conservative margins in the acceptable operation time. In this contribution, investigations on methods for an improved assessment of fatigue life assessment based on microstructural aspects (specifically in the view of piping systems) are presented. The focus is on the metastable austenitic steel AISI 347 (X6CrNiNb18-10) under boiling water reactor operational conditions. In addition to strain-controlled fatigue tests and the hysteresis information, microstructural characterizations of the damage evolution are performed. Fatigue tests are equipped with magnetic and resistometric sensors to measure a different kind of material response correlated with the damage states. The information obtained is used for an improved derivation of fatigue life evaluations of piping systems. The StrainLife approach and its specific instrumentation is proposed and discussed. In this approach, the number of strain-controlled fatigue tests is basically reduced by an order of magnitude when compared to traditional procedures. A software tool (as a module of the structural analysis code PROST) has been developed to assist users in evaluating and incorporating the respective data and to derive the subsequent fatigue life curves. As an outlook, further development is addressed to transfer the methodology to the assessment of residual fatigue life of components being exposed to ageing in operation.

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In order to optimize resource efficiency, glass fiber-reinforced polymers (GFRP) have been implemented in recent years in a wide range of applications of transport industries. In this context, GFR-epoxy (GFR-EP) is currently being used mainly because of their sufficiently investigated properties and production processes. Polyurethane (PU), however, shows advantages in terms of energy efficiency and damage tolerance. The aim of this study is the characterization of the fatigue behavior of GFR-PU by stepwise exploration of damage development on microscopic level. Therefore, multiple amplitude and constant amplitude tests have been carried out. Hysteresis and temperature measurements were applied in order to investigate the damage processes and correlated with in situ computed tomography (CT) in intermitting tests. The damage development and mechanisms could be characterized and separated. The results confirm known GFRP damage characteristics, whereas also material-specific peculiarities regarding crack development could be revealed.