<p>Power plant piping systems are subjected to multiple changes in their configurations during the various stages of their operation. These conditions lead to changes in loading conditions to the piping system, culminating into crack initiation at the highly stressed location. Thus, fatigue crack growth (FCG) studies play a vital role in demonstrating the structural integrity of the power plant piping system. Computational FCG studies play a vital role in the leak-before-break (LBB) &nbsp;demonstration of power plant piping system. Recent advancements in this domain have led to the use of fracture mechanics-based numerical crack growth analysis. A validated numerical method for the prototype-sized piping system can provide a fast and robust estimate of the crack growth data. Significant challenges to be addressed in this context are traced to be the identification of (i) numerical tool, which can handle a computationally intense finite element model of a prototype pipe bend, (ii) suitable FCG model and (iii) proper FCG material parameters. &nbsp;Traditionally, numerical FCG is simulated using material parameters generated based on CT specimen tests. But, such an approach is inadequate to predict crack growth behaviour in large-sized pipe bends; the major difficulty being its inability to address the residual compressive stress locked during the rolling process of pipe fabrication.</p><p>Development of prototype-based material parameters for FCG simulation is one of the potential alternatives to address the above issue. Despite this fact, crack growth simulation with the deployment of prototype-based material parameters are not reported so far. Though this approach is interesting, it is difficult to generalise it to all the geometries. Further, the fabrication assisted residual stress depends upon pipe dimensions also. Despite its shortcomings, it has been demonstrated that a numerical simulation with the material parameters derived from the prototype test results could capture the realistic FCG behaviour in the case of a prototype-sized power plant pipe bend. &nbsp;These results lead an initial step towards establishing the role of the prototype tests and provide a new framework in the generation of prototype-based material parameters for numerical simulation.</p>

Role of Material Parameters in Numerical Crack Growth Simulation: A Specimen Level and Prototype-Based Approach for Piping System

Paper Proceedings: https://asmedigitalcollection.asme.org/PVP/PVP2021/volume/85314

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