COMPUTATIONAL MODELING TO ENHANCE NDE EXPERIMENTAL ASSESSMENT OF HIGH TEMPERATURE CORROSION DAMAGE OF NEAR SURFACE FURNACE/REACTOR STRUCTURAL MATERIAL

摘要

This study reports on the use of finite element modeling, COMSOL, to investigate ultrasonic methods to detect early stages of corrosion where the indications are limited to much more subtle changes in material lattice conditions such as carburization or internal oxidation. These subtle defects do not include any cracking or pitting but, rather, are characterized by a relatively slight change in material density and elasticity. The propagation and scattering of ultrasonic guided waves in a 2-D geometry was modeled to study the signal produced by near surface second phase growth from high temperature chemical reactions in reactor/furnace structural materials. The simulation results indicate that it is indeed possible to detect these types of subtle defects using a guided wave approach. The modeling is used to allow for better experimental design to achieve NDE data of mechanistic interpretation of the microstructure-mechanical behavior of reactor/furnace material during service.