Abstract
This work presents methodologies for the examination of uncertainties in loading
conditions for incorporation in probabilistic creep-fatigue (CF) crack initiation
assessments. These approaches are based on the use of plant data for tran
sient (TR) as well as steady-operating (SO) conditions, with both potentially
having large contributions towards creep-fatigue damage. Conventionally, the
stress-states in a boiler plant component are found using thermal and mechani
cal (elastic) finite element (FE) models. The main inputs to these models are the
boiler steam temperatures, and the outputs are the six stress components (SCs)
and the metal temperature (MT) at the assessment location(s) of interest. The
proposed methodologies were developed based on experience gained from examining a tube-plate (TP) plant component, for which historical data was available. In a probabilistic assessment, the aim of these approaches is to replace time intensive FE runs with probabilistic alternatives which incorporate the variabilities in the loading conditions of interest. The value of these approaches lies in the avoidance of running FE models for every probabilistic trial (of which there typically may be more than 104), which would be computationally prohibitive.
conditions for incorporation in probabilistic creep-fatigue (CF) crack initiation
assessments. These approaches are based on the use of plant data for tran
sient (TR) as well as steady-operating (SO) conditions, with both potentially
having large contributions towards creep-fatigue damage. Conventionally, the
stress-states in a boiler plant component are found using thermal and mechani
cal (elastic) finite element (FE) models. The main inputs to these models are the
boiler steam temperatures, and the outputs are the six stress components (SCs)
and the metal temperature (MT) at the assessment location(s) of interest. The
proposed methodologies were developed based on experience gained from examining a tube-plate (TP) plant component, for which historical data was available. In a probabilistic assessment, the aim of these approaches is to replace time intensive FE runs with probabilistic alternatives which incorporate the variabilities in the loading conditions of interest. The value of these approaches lies in the avoidance of running FE models for every probabilistic trial (of which there typically may be more than 104), which would be computationally prohibitive.
| Original language | English |
|---|---|
| Article number | 104134 |
| Number of pages | 11 |
| Journal | International Journal of Pressure Vessels and Piping |
| Volume | 187 |
| Early online date | 19 Jul 2020 |
| DOIs | |
| Publication status | Published - 1 Nov 2020 |
Keywords
- creep
- damage
- plant loading
- uncertainties
- probabalistic