Session: 17-01-01: Research Posters

Paper Number: 143445

143445 - Small Punch Test-Based Fatigue Damage Assessment 

In today’s world, where energy resources are increasingly scarce and the imperative to mitigate climate change accelerates, the optimization of energy generation processes stands as a critical endeavor. Thermal and nuclear power plants, serving as pivotal pillars in global energy production, hold the key to meeting growing energy demands while minimizing environmental impacts. Even marginal improvements in the efficiency of these plants can yield substantial benefits, contributing to energy security and sustainability.

Amidst the quest for enhanced efficiency, the evolution of next-generation power plants is centered on elevating performance levels while concurrently addressing environmental concerns, notably through the adoption of higher steam temperatures. However, achieving these objectives requires a profound understanding of the mechanical properties inherent in the materials employed within these plants' structural frameworks.

The safety and resilience of power plants operating at heightened steam temperatures are contingent upon a comprehension of crucial mechanical properties such as tensile strength, creep, and fatigue. Traditionally, the assessment of these properties has been conducted through uniaxial tests (UT), wherein specimens are subjected to direct stress to analyze their mechanical behavior. While UT methodologies offer valuable insights into material characteristics, their resource-intensive and time-consuming nature poses inherent limitations, hindering the pace of material evaluation and development.

In response to these challenges, the small punch test (SPT) has emerged as a promising alternative. By leveraging smaller specimen sizes, SPT conserves materials and expedites testing processes, facilitating more rapid assessments of material properties. Unlike UT, which directly measures strain and stress, SPT evaluates displacement and load, necessitating the establishment of correlations between the two methodologies for precise material property evaluations. However, the differing stress application mechanisms employed in UT and SPT present complexities in achieving seamless correlation between the two techniques.

While prior research has made notable strides in elucidating the tensile and creep properties of materials using SPT, the characterization of their fatigue properties remains insufficiently defined. Consequently, the primary objective of this study is to develop a comprehensive methodology for assessing fatigue damage utilizing SPT. This endeavor encompasses the creation of a robust fatigue model to analyze fully reversed fatigue damage under small punch test conditions, employing advanced finite element analysis with dynamic friction. Additionally, S-N curves, which are essential for fatigue assessment, will be derived exclusively from small punch fatigue test data.

The validation of this approach entails a rigorous comparison of simulation results with S-N curves obtained through conventional UT procedures, thereby confirming the efficacy and reliability of the proposed SPT-based fatigue damage assessment methodology. Ultimately, the insights gleaned from this study hold the potential to significantly advance the understanding and evaluation of material properties critical for the safe and efficient operation of next-generation power plants.

Presenting Author: Moon Ki Kim Sungkyunkwan University

Presenting Author Biography: Prof. Moon Ki Kim received B.S. and M.S. degrees in Mechanical Engineering from Seoul National University in 1997 and 1999, respectively, and a Ph.D. degree from Johns Hopkins University in 2004. He served as an Assistant Professor in the Department of Mechanical and Industrial Engineering at the University of Massachusetts, Amherst from 2004 to 2008. In 2008, he joined Sungkyunkwan University, where he currently holds the position of Professor in the School of Mechanical Engineering. His research interests are focused on computational structural biology based on robot kinematics, multiscale modeling and simulation, and mechanical property characterization.

Authors:

Sangyeop Kim Sungkyunkwan University
Moon Ki Kim Sungkyunkwan University