米国滞在中のISEM2025最終日にうれしい知らせが参りました。米国非破壊検査学会の学会誌であるMaterials Evaluationに投稿していた論文の受理通知です。
論文の結果自体は一昨年度博士を修了した冨澤君の博士論文のものです。早くどこかで発表しなければと考えていたところ、丁度Materials Evaluation誌でこのような研究に関する特集号を企画しているとのことだったので投稿し、無事受理されたという経緯です。
論文の概要は以下。
Title: Probabilistic sizing of a fatigue crack on type 304 austenitic stainless steel from eddy current signals
Abstract: This study attempted to probabilistically evaluate the size of a fatigue crack on a type 304 austenitic stainless flat plate from eddy current signals. Three fatigue cracks, whose depths ranged from 2 mm to 5 mm, were introduced into the plates using a four-point bending test. After the starter notches for the test were removed, eddy current testing was conducted using a differential-type pluspoint probe with a frequency of 200 kHz to gather signals due to cracks. The fatigue crack was modeled as a rectangular continuous domain with constant width and uniform electromagnetic properties inside. As mechanical damage transforms the austenitic phase into the martensitic phase, not only conductivity but also the permeability of the domain were explicitly considered. The depth and length of the cracks were evaluated using a Bayesian-based inverse algorithm assuming that the electromagnetic properties of a crack are either known (equal to air) or unknown. When a crack was modeled as air, the evaluated crack sizes deviated considerably from the actual sizes. By contrast, assuming the electromagnetic properties to be unknown provided better evaluations with their quantified uncertainty.