Host: Science Council of Japan
Co-host: Japan Society for Safety Engineering, The Japanese Geotechnical Society, Japan Society of Civil Engineers, The Japan Society of Mechanical Engineers, Architectural Institute of Japan, The Japan Society for Aeronautical and Space Sciences, The Society of Materials Science, Japan, The Japan Society of Naval Architects and Ocean Engineers
Name : The 10th Japan Conference on Structural Safety and Reliability
Number : 10
Location : [in Japanese]
Date : October 25, 2023 - October 27, 2023
Hydrogen and natural gas blending can be considered an important energy technology in terms of utilization of the existing infrastructure, which has a significant cost impact on the deployment of hydrogen infrastructures, and the smooth transition of energy systems. In this study, fatigue crack growth tests were carried out in air, hydrogen (H2), 20% H2 mixed methane (CH4) and 20% H2 mixed natural gases. Three kinds of natural gases with different oxygen (O2) impurity concentrations were used in order to characterize the effect of hydrogen on the fatigue crack growth behavior in natural gas in conjunction with the effect of the O2 impurity. The pressure of the gases except for air was 1 MPa. The test material was JIS SCM435 low-alloy steel. In the H2 and the 20% H2 mixed CH4, the fatigue crack growth rates were accelerated. The acceleration was less in the 20% H2 mixed CH4 compared to that in the H2. It is presumed that the lower hydrogen effect was due to reduced partial H2 pressure in the mixture. This was confirmed by the crack growth test in 0.2 MPa H2 resulting in the same crack growth rate as in the mixture. Regarding the fatigue crack growth tests in the 20% H2 mixed natural gases, acceleration of the fatigue crack growth rate and suppression of the acceleration due to oxygen were observed. The oxygen effect increased with the increase in the oxygen concentration and was well-evaluated by the predictive model of hydrogen-assisted crack growth in the presence of oxygen proposed by Somerday et al.