Notch Support for LCF-Loading: A Fracture Mechanics Approach
| Autor: | Henning Almstedt, Matthias Oechsner, Christian Kontermann, Alfred Scholz |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Engineering
Work (thermodynamics) FEM-based Fracture Mechanics business.industry System of measurement Notch Support Fracture mechanics 02 engineering and technology Structural engineering Plasticity 021001 nanoscience & nanotechnology Power (physics) Crack closure Cyclic J-Integral 020303 mechanical engineering & transports 0203 mechanical engineering PICC Fracture (geology) 0210 nano-technology business Voltage drop Earth-Surface Processes |
| Zdroj: | Procedia Structural Integrity. 2:3125-3134 |
| ISSN: | 2452-3216 |
| DOI: | 10.1016/j.prostr.2016.06.390 |
| Popis: | The demand for an increase in flexible operation of power plants provides a key challenge. Solutions for new components as well as for units in operation have to be developed to safely allow for more load cycles and faster start-up times. One way to realize this is to improve the lifetime assessment methods by reducing implied conservatisms. The presented work focuses on the description of Notch Support Effects at elevated temperatures for the LCF-Regime. At first, a tailored experimental set-up using notched round bars is introduced. Those tests are performed under global strain control and are equipped with an Alternating Current Potential Drop (ACPD) measurement system. The experimental results show that the crack growth phase up to a so called “technical crack size” is of major relevance to describe notch support effects. That is why within the second part of this paper, a concept is introduced to consider this early crack growth phase within a lifetime assessment approach. Within this concept, fracture mechanical parameters are determined by applying a novel energy-based Finite Element approach. Suggestions are presented to define proper values of the cyclic J -Integral as well as of the amount of Plasticity Induced Crack Closure (PICC). Finally, the concept is applied and validated by comparing the simulation approach with the experimental results. Keywords: Notch Support, Fracture Mechanics, Cyclic J -Integral, PICC |
| Databáze: | OpenAIRE |
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