九州大学カーボンニュートラル・エネルギー国際研究所（I²CNER)、水素適合材料研究部門主任研究者Petros Sofronis所長及びBrian Somerday主任研究者・水素適合材料研究部門長ら研究グループの研究成果が『The Journal of The Minerals, Metals & Materials Society (TMS)』に掲載されました。

■概要

The failure of hydrogen containment components is generally associated with subcritical cracking. Understanding subcritical crack growth behavior and its dependence on material and environmental variables can lead to methods for designing structural components in a hydrogen environment and will be beneficial in developing materials resistant to hydrogen embrittlement. In order to identify the issues underlying crack propagation and arrest, we present a model for hydrogen-induced stress-controlled crack propagation under sustained loading. The model is based on the assumptions that (I) hydrogen reduces the material fracture strength and (II) crack propagation takes place when the opening stress over the characteristic distance ahead of a crack tip is greater than the local fracture strength. The model is used in a finite-element simulation of crack propagation coupled with simultaneous hydrogen diffusion in a model material through nodal release. The numerical simulations show that the same physics, i.e., diffusion-controlled crack propagation, can explain the existence of both stages I and II in the velocity versus stress intensity factor (V–K) curve.

■論文

* Title: On Modeling Hydrogen-Induced Crack Propagation Under Sustained Load

* Authors: Mohsen Dadfarnia, Brian p. Somerday, Philip E. Schembri, Petros Sofronis, James W. Foulk, Kevin A. Nibur & Dorian K. Balch

* DOI: 10.1007/s11837-014-1050-8

* Publication Date: August 2014